ECC Class

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The ECC (Elliptic Curve Cryptography) class implements ECDSA, EdDSA, ECDH, and ECIES operations.

Syntax

ipworksencrypt.ECC

Remarks

The ECC (Elliptic Curve Cryptography) class implements ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm), ECDH (Elliptic Curve Diffie Hellman), and ECIES (Elliptic Curve Integrated Encryption Scheme) operations. The class supports the following common operations:

• CreateKey allows key creation using algorithms such as secp256r1, secp384r1, secp521r1, X25519, X448, Ed25519, Ed448, and more.
• ComputeSecret computes a shared secret between two parties using a public and private key (ECDH).
• Sign and VerifySignature provides a way to digitally sign data and verify signatures (ECDSA and EdDSA).
• Encrypt and Decrypt encrypt and decrypt data using a public and private key (ECIES).

The class is very flexible and offers many properties and configuration settings to configure it. The sections below detail the use of the class for each of the major operations listed above.

Key Creation and Management

CreateKey creates a new public and private key.

When this method is called, Key is populated with the generated key. The PublicKey and PrivateKey fields hold the PEM formatted public and private key for ease of use. This is helpful for storing or transporting keys more easily.

The KeyAlgorithm parameter specifies the algorithm for which the key is intended to be used. Possible values are:

NIST, Koblitz, and Brainpool Curve Notes

Keys for use with NIST curves (secp256r1, secp384r1, secp521r1), Koblitz curves (secp160k1, secp192k1, secp224k1, secp256k1), and Brainpool curves are made up of a number of individual parameters.

The public key consists of the following parameters:

• Rx
• Ry

The private key consists of one value:

• K

Curve25519 and Curve448 Notes

Keys for use with Curve25519 or Curve448 are made up of a private key and public key field.

XPk holds the public key.

XSk holds the private key.

Create Key Example (secp256r1 - PEM)

//Create a key using secp256r1 Ecc ecc = new Ecc(); ecc.CreateKey("secp256r1"); Console.WriteLine(ecc.Key.Algorithm); //outputs enum value "eaSecp256r1" string privKey = ecc.Key.PrivateKey; //PEM formatted key string pubKey = ecc.Key.PublicKey; //PEM formatted key //Load the saved key ecc.Reset(); ecc.Key.PublicKey = pubKey; ecc.Key.PrivateKey = privKey; Console.WriteLine(ecc.Key.Algorithm); //outputs enum value "eaSecp256r1"

Create Key Example (secp256r1 - Raw Key Params)

//Create a key using secp256r1 and store/load the key using the individual params Ecc ecc = new Ecc(); ecc.CreateKey("secp256r1"); Console.WriteLine(ecc.Key.Algorithm); //outputs enum value "eaSecp256r1" byte[] K = ecc.Key.KB; //Private key param byte[] Rx = ecc.Key.RxB; //Public key param byte[] Ry = ecc.Key.RyB; //Public key param //Load the saved key ecc.Reset(); ecc.Key.Algorithm = ECAlgorithms.eaSecp256r1; //This MUST be set manually when using key params directly ecc.Key.KB = K; ecc.Key.RxB = Rx; ecc.Key.RyB = Ry; Console.WriteLine(ecc.Key.Algorithm); //outputs enum value "eaSecp256r1"

Create Key Example (Ed25519 - PEM)

//Create a key using Ed25519 Ecc ecc = new Ecc(); ecc.CreateKey("Ed25519"); Console.WriteLine(ecc.Key.Algorithm); //outputs enum value "eaEd25519" string privKey = ecc.Key.PrivateKey; //PEM formatted key string pubKey = ecc.Key.PublicKey; //PEM formatted key //Load the saved key ecc.Reset(); ecc.Key.PublicKey = pubKey; ecc.Key.PrivateKey = privKey; Console.WriteLine(ecc.Key.Algorithm); //outputs enum value "eaEd25519"

Create Key Example (Ed25519 - Raw Key Params)

//Create a key using Ed25519 and store/load the key using the individual params Ecc ecc = new Ecc(); ecc.CreateKey("Ed25519"); Console.WriteLine(ecc.Key.Algorithm); //outputs enum value "eaEd25519" byte[] XPk = ecc.Key.XPkB; //Public key data byte[] XSk = ecc.Key.XSkB; //Secret key data //Load the saved key ecc.Reset(); ecc.Key.Algorithm = ECAlgorithms.eaEd25519; //This MUST be set manually when using key params directly ecc.Key.XPkB = XPk; ecc.Key.XSkB = XSk; Console.WriteLine(ecc.Key.Algorithm); //outputs enum value "eaEd25519"

Compute Secret (ECDH)

This method computes a shared secret using Elliptic Curve Diffie Hellman (ECDH).

When this method is called, the class will use the public key specified by RecipientKey (or RecipientCert) and the private key specified by Key to compute a shared secret, or secret agreement. The ComputeSecretKDF property specifies the Hash or HMAC algorithm that is applied to the raw secret. The resulting value is held by SharedSecret. The following properties are applicable when calling this method:

• Key (required)
• RecipientKey or RecipientCert (required)
• ComputeSecretKDF (optional)

See ComputeSecretKDF for details on advanced settings that may be applicable for the chosen algorithm.

Keys created with the Ed25519 and Ed448 algorithms are not supported when calling this method.

Compute Secret Example

//Create a key for Party 1 Ecc ecc1 = new Ecc(); ecc1.CreateKey("X25519"); string ecc1_priv = ecc1.Key.PrivateKey; string ecc1_pub = ecc1.Key.PublicKey; //Create a key for Party 2 Ecc ecc2 = new Ecc(); ecc2.CreateKey("X25519"); string ecc2_priv = ecc2.Key.PrivateKey; string ecc2_pub = ecc2.Key.PublicKey; //Note: the public keys must be exchanged between parties by some mechanism //Create the shared secret on Party 1 ecc1.Reset(); ecc1.Key.PrivateKey = ecc1_priv; //Private key of this party ecc1.RecipientKey.PublicKey = ecc2_pub; //Public key of other party ecc1.UseHex = true; //Hex encodes the shared secret bytes for easier display/storage ecc1.ComputeSecret(); Console.WriteLine(ecc1.SharedSecret); //Create the shared secret on Party 2 ecc2.Reset(); ecc2.Key.PrivateKey = ecc2_priv; //Private key of this party ecc2.RecipientKey.PublicKey = ecc1_pub; //Public key of other party ecc2.UseHex = true; //Hex encodes the shared secret bytes for easier display/storage ecc2.ComputeSecret(); Console.WriteLine(ecc2.SharedSecret); //This will match the shared secret created by ecc1.

Signing (ECDSA and EdDSA)

Sign will create a hash signature using ECDSA or EdDSA. The class will use the key specified by Key to hash the input data and sign the resulting hash.

Key must contain a private key created with a valid ECDSA or EdDSA algorithm. Algorithm is used to determine the eligibility of the key for this operation. Supported algorithms for signing are:

• NIST Curves (secp256r1, secp384r1, secp521r1)
• Koblitz Curves (secp160k1, secp192k1, secp224k1, secp256k1)
• Brainpool Curves
• Ed25519 and Ed448

See CreateKey for details about key creation and algorithms.

When this method is called, data will be read from the stream set by SetInputStream, InputFile, or InputMessage.

The hash to be signed will be computed using the specified HashAlgorithm. The computed hash is stored in the HashValue property. The signed hash is stored in the HashSignature property.

To sign a hash without first computing it, set HashValue to a previously computed hash for the input data. Note: HashValue is not applicable when signing with a PureEdDSA algorithm such as Ed25519 or Ed448.

The Progress event will fire with updates for the hash computation progress only. The hash signature creation process is quick and does not require progress updates.

After calling Sign, the public key must be sent to the recipient along with HashSignature and the original input data so the other party may perform signature verification.

The following properties are applicable when calling this method:

• Key (required)
• HashAlgorithm (applicable to ECDSA only)
• HashEdDSA (applicable to EdDSA only)
• HashValue (not applicable to PureEdDSA)
• UseHex

The following properties are populated after calling this method:

• HashValue
• HashSignature

EdDSA Notes

When the Algorithm is Ed25519 or Ed448, the following additional parameters are applicable:

• HashEdDSA
• EdDSAContext

EdDSA keys can be used with a PureEdDSA algorithm (Ed25519/Ed448) or a HashEdDSA (Ed25519ph, Ed448ph) algorithm. This is controlled by the HashEdDSA property. By default, the class uses the PureEdDSA algorithm.

The PureEdDSA algorithm requires two passes over the input data but provides collision resilience. The collision resilience of PureEdDSA means that even if it is feasible to compute collisions for the hash function, the algorithm is still secure. When using PureEdDSA, HashValue is not applicable.

When using a HashEdDSA algorithm, the input is pre-hashed and supports a single pass over the data during the signing operation. To enable HashEdDSA, set HashEdDSA to True.

To specify context data when using Ed25519 or Ed448, set EdDSAContext.

Sign And Verify Example (ECDSA)

//Create an ECDSA key on Party 1 Ecc ecc1 = new Ecc(); ecc1.CreateKey("secp256r1"); string ecc1_priv = ecc1.Key.PrivateKey; string ecc1_pub = ecc1.Key.PublicKey; //Sign the data on Party 1 string originalData = "hello ecc"; ecc1.Reset(); ecc1.Key.PrivateKey = ecc1_priv; ecc1.InputMessage = originalData; ecc1.UseHex = true; //Hex encode the hash signature for ease of use. ecc1.Sign(); string hashSignature = ecc1.HashSignature; //Transmit the hash signature, public key, and original data to Party 2 //Verify the data on Party 2 Ecc ecc2 = new Ecc(); ecc2.SignerKey.PublicKey = ecc1_pub; ecc2.InputMessage = originalData; ecc2.HashSignature = hashSignature; ecc2.UseHex = true; //Decode the hex encoded hash signature bool isVerified = ecc2.VerifySignature();

Sign And Verify Example (EdDSA - PureEdDSA)

//Create an EdDSA key on Party 1 Ecc ecc1 = new Ecc(); ecc1.CreateKey("ed25519"); string ecc1_priv = ecc1.Key.PrivateKey; string ecc1_pub = ecc1.Key.PublicKey; //Sign the data on Party 1 string originalData = "hello ecc"; ecc1.Reset(); ecc1.Key.PrivateKey = ecc1_priv; ecc1.InputMessage = originalData; ecc1.UseHex = true; //Hex encode the hash signature for ease of use. ecc1.Sign(); string hashSignature = ecc1.HashSignature; //Transmit the hash signature, public key, and original data to Party 2 //Verify the data on Party 2 Ecc ecc2 = new Ecc(); ecc2.SignerKey.PublicKey = ecc1_pub; ecc2.InputMessage = originalData; ecc2.HashSignature = hashSignature; ecc2.UseHex = true; //Decode the hex encoded hash signature bool isVerified = ecc2.VerifySignature();

Sign And Verify Example (EdDSA - HashEdDSA)

//Create an EdDSA key on Party 1 Ecc ecc1 = new Ecc(); ecc1.CreateKey("ed25519"); string ecc1_priv = ecc1.Key.PrivateKey; string ecc1_pub = ecc1.Key.PublicKey; //Sign the data on Party 1 string originalData = "hello ecc"; ecc1.Reset(); ecc1.Key.PrivateKey = ecc1_priv; ecc1.InputMessage = originalData; ecc1.UseHex = true; //Hex encode the hash signature for ease of use. ecc1.HashEdDSA = true; //Use "ed25519ph" ecc1.Sign(); string hashSignature = ecc1.HashSignature; //Transmit the hash signature, public key, and original data to Party 2 //Verify the data on Party 2 Ecc ecc2 = new Ecc(); ecc2.SignerKey.PublicKey = ecc1_pub; ecc2.InputMessage = originalData; ecc2.HashSignature = hashSignature; ecc2.HashEdDSA = true; ecc2.UseHex = true; //Decode the hex encoded hash signature bool isVerified = ecc2.VerifySignature();

Verifying (ECDSA and EdDSA)

VerifySignature will verify a hash signature and return True if successful or False otherwise.

Before calling this method, specify the input file by setting SetInputStream, InputFile, or InputMessage.

A public key and the hash signature are required to perform the signature verification. Specify the public key in SignerKey. Specify the hash signature in HashSignature.

When this method is called, the class will compute the hash for the specified file and populate HashValue. It will verify the signature using the specified SignerKey and HashSignature.

To verify the hash signature without first computing the hash, simply specify HashValue before calling this method. Note: HashValue is not applicable when the message was signed with a PureEdDSA algorithm such as Ed25519 or Ed448.

The Progress event will fire with updates for the hash computation progress only. The hash signature verification process is quick and does not require progress updates.

The following properties are applicable when calling this method:

• HashSignature (required)
• SignerKey (required)
• EdDSAContext (applicable to EdDSA only)
• HashAlgorithm (applicable to ECDSA only)
• HashEdDSA (applicable to EdDSA only)
• HashValue (not applicable to PureEdDSA)
• UseHex

Sign And Verify Example (ECDSA)

//Create an ECDSA key on Party 1 Ecc ecc1 = new Ecc(); ecc1.CreateKey("secp256r1"); string ecc1_priv = ecc1.Key.PrivateKey; string ecc1_pub = ecc1.Key.PublicKey; //Sign the data on Party 1 string originalData = "hello ecc"; ecc1.Reset(); ecc1.Key.PrivateKey = ecc1_priv; ecc1.InputMessage = originalData; ecc1.UseHex = true; //Hex encode the hash signature for ease of use. ecc1.Sign(); string hashSignature = ecc1.HashSignature; //Transmit the hash signature, public key, and original data to Party 2 //Verify the data on Party 2 Ecc ecc2 = new Ecc(); ecc2.SignerKey.PublicKey = ecc1_pub; ecc2.InputMessage = originalData; ecc2.HashSignature = hashSignature; ecc2.UseHex = true; //Decode the hex encoded hash signature bool isVerified = ecc2.VerifySignature();

Sign And Verify Example (EdDSA - PureEdDSA)

//Create an EdDSA key on Party 1 Ecc ecc1 = new Ecc(); ecc1.CreateKey("ed25519"); string ecc1_priv = ecc1.Key.PrivateKey; string ecc1_pub = ecc1.Key.PublicKey; //Sign the data on Party 1 string originalData = "hello ecc"; ecc1.Reset(); ecc1.Key.PrivateKey = ecc1_priv; ecc1.InputMessage = originalData; ecc1.UseHex = true; //Hex encode the hash signature for ease of use. ecc1.Sign(); string hashSignature = ecc1.HashSignature; //Transmit the hash signature, public key, and original data to Party 2 //Verify the data on Party 2 Ecc ecc2 = new Ecc(); ecc2.SignerKey.PublicKey = ecc1_pub; ecc2.InputMessage = originalData; ecc2.HashSignature = hashSignature; ecc2.UseHex = true; //Decode the hex encoded hash signature bool isVerified = ecc2.VerifySignature();

Sign And Verify Example (EdDSA - HashEdDSA)

//Create an EdDSA key on Party 1 Ecc ecc1 = new Ecc(); ecc1.CreateKey("ed25519"); string ecc1_priv = ecc1.Key.PrivateKey; string ecc1_pub = ecc1.Key.PublicKey; //Sign the data on Party 1 string originalData = "hello ecc"; ecc1.Reset(); ecc1.Key.PrivateKey = ecc1_priv; ecc1.InputMessage = originalData; ecc1.UseHex = true; //Hex encode the hash signature for ease of use. ecc1.HashEdDSA = true; //Use "ed25519ph" ecc1.Sign(); string hashSignature = ecc1.HashSignature; //Transmit the hash signature, public key, and original data to Party 2 //Verify the data on Party 2 Ecc ecc2 = new Ecc(); ecc2.SignerKey.PublicKey = ecc1_pub; ecc2.InputMessage = originalData; ecc2.HashSignature = hashSignature; ecc2.HashEdDSA = true; ecc2.UseHex = true; //Decode the hex encoded hash signature bool isVerified = ecc2.VerifySignature();

Encrypting (ECIES)

Encrypt encrypts the specified data with the ECDSA public key specified in RecipientKey.

Encryption is performed using ECIES which requires an ECDSA key. RecipientKey must contain an ECDSA key. Algorithm is used to determine the eligibility of the key for this operation. Supported algorithms for encryption are:

• NIST Curves (secp256r1, secp384r1, secp521r1)
• Koblitz Curves (secp160k1, secp192k1, secp224k1, secp256k1)
• Brainpool Curves

See CreateKey for details about key creation and algorithms.

When this method is called, the class will encrypt the specified data using ECIES and the encrypted data will be output. To hex encode the output, set UseHex to True.

The following properties are applicable when calling this method:

• EncryptionAlgorithm
• HMACAlgorithm
• HMACOptionalInfo
• HMACKeySize
• IV
• KDF
• KDFHashAlgorithm
• KDFOptionalInfo
• UseHex

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

• SetInputStream
• InputFile
• InputMessage

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

• SetOutputStream
• OutputFile
• OutputMessage: The output data is written to this property if no other destination is specified.

When using streams, you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.

Encrypt and Decrypt Example

//Create an ECDSA key on Party 2 Ecc ecc2 = new Ecc(); ecc2.CreateKey("secp256r1"); string ecc2_priv = ecc2.Key.PrivateKey; string ecc2_pub = ecc2.Key.PublicKey; //Transmit public key to Party 1 //Encrypt the message on Party 1 using public key from Party 2 Ecc ecc1 = new Ecc(); ecc1.InputMessage = "hello ecc"; ecc1.RecipientKey.PublicKey = ecc2_pub; ecc1.UseHex = true; ecc1.Encrypt(); string encryptedMessage = ecc1.OutputMessage; //Transmit the encrypted message to Party 2 //Decrypt the message using the private key for Party 2 ecc2.Key.PrivateKey = ecc2_priv; ecc2.InputMessage = encryptedMessage; ecc2.UseHex = true; ecc2.Decrypt(); Console.WriteLine(ecc2.OutputMessage);

Encrypt and Decrypt Example (AES with IV)

//Create an ECDSA key on Party 2 Ecc ecc2 = new Ecc(); ecc2.CreateKey("secp256r1"); string ecc2_priv = ecc2.Key.PrivateKey; string ecc2_pub = ecc2.Key.PublicKey; //Transmit public key to Party 1 //Encrypt the message on Party 1 using public key from Party 2 Ecc ecc1 = new Ecc(); //Use an IV (16 bytes for AES) - In a real environment this should be random byte[] IV = new byte[] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F }; ecc1.EncryptionAlgorithm = EccEncryptionAlgorithms.iesAES; ecc1.IVB = IV; ecc1.InputMessage = "hello ecc"; ecc1.RecipientKey.PublicKey = ecc2_pub; ecc1.UseHex = true; ecc1.Encrypt(); string encryptedMessage = ecc1.OutputMessage; //Transmit the encrypted message and the IV to Party 2 //Decrypt the message using the private key for Party 2 and the IV ecc2.EncryptionAlgorithm = EccEncryptionAlgorithms.iesAES; ecc2.IVB = IV; ecc2.Key.PrivateKey = ecc2_priv; ecc2.InputMessage = encryptedMessage; ecc2.UseHex = true; ecc2.Decrypt(); Console.WriteLine(ecc2.OutputMessage);

Encrypt and Decrypt Example (XOR Encryption Algorithm)

//Create an ECDSA key on Party 2 Ecc ecc2 = new Ecc(); ecc2.CreateKey("secp256r1"); string ecc2_priv = ecc2.Key.PrivateKey; string ecc2_pub = ecc2.Key.PublicKey; //Transmit public key to Party 1 //Encrypt the message on Party 1 using public key from Party 2 Ecc ecc1 = new Ecc(); ecc1.EncryptionAlgorithm = EccEncryptionAlgorithms.iesXOR; ecc1.InputMessage = "hello ecc"; ecc1.RecipientKey.PublicKey = ecc2_pub; ecc1.UseHex = true; ecc1.Encrypt(); string encryptedMessage = ecc1.OutputMessage; //Transmit the encrypted message to Party 2 //Decrypt the message using the private key for Party 2 ecc2.EncryptionAlgorithm = EccEncryptionAlgorithms.iesXOR; ecc2.Key.PrivateKey = ecc2_priv; ecc2.InputMessage = encryptedMessage; ecc2.UseHex = true; ecc2.Decrypt(); Console.WriteLine(ecc2.OutputMessage);

Encrypt and Decrypt Example (KDF Options)

//Create an ECDSA key on Party 2 Ecc ecc2 = new Ecc(); ecc2.CreateKey("secp256r1"); string ecc2_priv = ecc2.Key.PrivateKey; string ecc2_pub = ecc2.Key.PublicKey; //Transmit public key to Party 1 //Encrypt the message on Party 1 using public key from Party 2 Ecc ecc1 = new Ecc(); ecc1.KDF = "KDF1"; //Use KDF1 ecc1.KDFHashAlgorithm = EccKDFHashAlgorithms.iesSHA1; ecc1.Config("KDFOptionalInfo=202122232425262728292a2b2c2d2e2f"); //Hex encoded string ecc1.InputMessage = "hello ecc"; ecc1.RecipientKey.PublicKey = ecc2_pub; ecc1.UseHex = true; ecc1.Encrypt(); string encryptedMessage = ecc1.OutputMessage; //Transmit the encrypted message to Party 2 //Decrypt the message using the private key for Party 2 ecc2.KDF = "KDF1"; ecc2.KDFHashAlgorithm = EccKDFHashAlgorithms.iesSHA1; ecc2.Config("KDFOptionalInfo=202122232425262728292a2b2c2d2e2f"); ecc2.Key.PrivateKey = ecc2_priv; ecc2.InputMessage = encryptedMessage; ecc2.UseHex = true; ecc2.Decrypt(); Console.WriteLine(ecc2.OutputMessage);

Decrypting (ECIES)

Decrypt decrypts the specified data with the ECDSA private key specified in Key.

Decryption is performed using ECIES which requires an ECDSA key. Key must contain an ECDSA key. Algorithm is used to determine the eligibility of the key for this operation. Supported algorithms for encryption are:

• NIST Curves (secp256r1, secp384r1, secp521r1)
• Koblitz Curves (secp160k1, secp192k1, secp224k1, secp256k1)
• Brainpool Curves

See CreateKey for details about key creation and algorithms.

When this method is called, the class will decrypt the specified data using ECIES and the decrypted data will be output. If the input data was originally hex encoded, set UseHex to True.

The following properties are applicable when calling this method:

• EncryptionAlgorithm
• HMACAlgorithm
• HMACOptionalInfo
• HMACKeySize
• IV
• KDF
• KDFHashAlgorithm
• KDFOptionalInfo
• UseHex

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

• SetInputStream
• InputFile
• InputMessage

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

• SetOutputStream
• OutputFile
• OutputMessage: The output data is written to this property if no other destination is specified.

When using streams, you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.

Encrypt and Decrypt Example

//Create an ECDSA key on Party 2 Ecc ecc2 = new Ecc(); ecc2.CreateKey("secp256r1"); string ecc2_priv = ecc2.Key.PrivateKey; string ecc2_pub = ecc2.Key.PublicKey; //Transmit public key to Party 1 //Encrypt the message on Party 1 using public key from Party 2 Ecc ecc1 = new Ecc(); ecc1.InputMessage = "hello ecc"; ecc1.RecipientKey.PublicKey = ecc2_pub; ecc1.UseHex = true; ecc1.Encrypt(); string encryptedMessage = ecc1.OutputMessage; //Transmit the encrypted message to Party 2 //Decrypt the message using the private key for Party 2 ecc2.Key.PrivateKey = ecc2_priv; ecc2.InputMessage = encryptedMessage; ecc2.UseHex = true; ecc2.Decrypt(); Console.WriteLine(ecc2.OutputMessage);

Encrypt and Decrypt Example (AES with IV)

//Create an ECDSA key on Party 2 Ecc ecc2 = new Ecc(); ecc2.CreateKey("secp256r1"); string ecc2_priv = ecc2.Key.PrivateKey; string ecc2_pub = ecc2.Key.PublicKey; //Transmit public key to Party 1 //Encrypt the message on Party 1 using public key from Party 2 Ecc ecc1 = new Ecc(); //Use an IV (16 bytes for AES) - In a real environment this should be random byte[] IV = new byte[] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F }; ecc1.EncryptionAlgorithm = EccEncryptionAlgorithms.iesAES; ecc1.IVB = IV; ecc1.InputMessage = "hello ecc"; ecc1.RecipientKey.PublicKey = ecc2_pub; ecc1.UseHex = true; ecc1.Encrypt(); string encryptedMessage = ecc1.OutputMessage; //Transmit the encrypted message and the IV to Party 2 //Decrypt the message using the private key for Party 2 and the IV ecc2.EncryptionAlgorithm = EccEncryptionAlgorithms.iesAES; ecc2.IVB = IV; ecc2.Key.PrivateKey = ecc2_priv; ecc2.InputMessage = encryptedMessage; ecc2.UseHex = true; ecc2.Decrypt(); Console.WriteLine(ecc2.OutputMessage);

Encrypt and Decrypt Example (XOR Encryption Algorithm)

//Create an ECDSA key on Party 2 Ecc ecc2 = new Ecc(); ecc2.CreateKey("secp256r1"); string ecc2_priv = ecc2.Key.PrivateKey; string ecc2_pub = ecc2.Key.PublicKey; //Transmit public key to Party 1 //Encrypt the message on Party 1 using public key from Party 2 Ecc ecc1 = new Ecc(); ecc1.EncryptionAlgorithm = EccEncryptionAlgorithms.iesXOR; ecc1.InputMessage = "hello ecc"; ecc1.RecipientKey.PublicKey = ecc2_pub; ecc1.UseHex = true; ecc1.Encrypt(); string encryptedMessage = ecc1.OutputMessage; //Transmit the encrypted message to Party 2 //Decrypt the message using the private key for Party 2 ecc2.EncryptionAlgorithm = EccEncryptionAlgorithms.iesXOR; ecc2.Key.PrivateKey = ecc2_priv; ecc2.InputMessage = encryptedMessage; ecc2.UseHex = true; ecc2.Decrypt(); Console.WriteLine(ecc2.OutputMessage);

Encrypt and Decrypt Example (KDF Options)

//Create an ECDSA key on Party 2 Ecc ecc2 = new Ecc(); ecc2.CreateKey("secp256r1"); string ecc2_priv = ecc2.Key.PrivateKey; string ecc2_pub = ecc2.Key.PublicKey; //Transmit public key to Party 1 //Encrypt the message on Party 1 using public key from Party 2 Ecc ecc1 = new Ecc(); ecc1.KDF = "KDF1"; //Use KDF1 ecc1.KDFHashAlgorithm = EccKDFHashAlgorithms.iesSHA1; ecc1.Config("KDFOptionalInfo=202122232425262728292a2b2c2d2e2f"); //Hex encoded string ecc1.InputMessage = "hello ecc"; ecc1.RecipientKey.PublicKey = ecc2_pub; ecc1.UseHex = true; ecc1.Encrypt(); string encryptedMessage = ecc1.OutputMessage; //Transmit the encrypted message to Party 2 //Decrypt the message using the private key for Party 2 ecc2.KDF = "KDF1"; ecc2.KDFHashAlgorithm = EccKDFHashAlgorithms.iesSHA1; ecc2.Config("KDFOptionalInfo=202122232425262728292a2b2c2d2e2f"); ecc2.Key.PrivateKey = ecc2_priv; ecc2.InputMessage = encryptedMessage; ecc2.UseHex = true; ecc2.Decrypt(); Console.WriteLine(ecc2.OutputMessage);

Property List

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The following is the full list of the properties of the class with short descriptions. Click on the links for further details.

Method List

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The following is the full list of the methods of the class with short descriptions. Click on the links for further details.

Event List

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The following is the full list of the events fired by the class with short descriptions. Click on the links for further details.

Config Settings

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The following is a list of config settings for the class with short descriptions. Click on the links for further details.

Certificate Property (ECC Class)

The certificate used for signing and decryption.

Syntax

public Certificate getCertificate();


public void setCertificate(Certificate certificate);

Remarks

This property specifies a certificate with a private key.

This may be set instead of Key, allowing a Certificate object to be used instead of a ECCKey object. This certificate is used when calling Sign and Decrypt. The specified certificate must have a private key.

If both this property and Key are specified, Key will be used and this property will be ignored.

Please refer to the Certificate type for a complete list of fields.

ComputeSecretKDF Property (ECC Class)

The key derivation function.

Syntax

public int getComputeSecretKDF();


public void setComputeSecretKDF(int computeSecretKDF);


Enumerated values:
  public final static int ekdSHA1 = 0;
  public final static int ekdSHA256 = 1;
  public final static int ekdSHA384 = 2;
  public final static int ekdSHA512 = 3;
  public final static int ekdMD2 = 4;
  public final static int ekdMD4 = 5;
  public final static int ekdMD5 = 6;
  public final static int ekdHMACSHA1 = 7;
  public final static int ekdHMACSHA256 = 8;
  public final static int ekdHMACSHA384 = 9;
  public final static int ekdHMACSHA512 = 10;
  public final static int ekdHMACMD5 = 11;
  public final static int ekdTLS = 12;
  public final static int ekdConcat = 13;

Default Value

1

Remarks

This property specifies the key derivation function (KDF) and algorithm to use when calling ComputeSecret.

Possible values are:

HMAC Notes

If an HMAC algorithm is selected, HMACKey may optionally be set to specify the key.

TLS Notes

When set to TLS, TLSSeed and TLSLabel are required. In addition, PrependSecret and AppendSecret are not applicable.

Concat Notes

If Concat is selected, the following configuration settings are applicable:

• ConcatAlgorithmId (required)
• ConcatPartyUInfo (required)
• ConcatPartyVInfo (required)
• ConcatSuppPubInfo
• ConcatSuppPrivInfo
• ConcatHashAlgorithm

EncryptionAlgorithm Property (ECC Class)

The encryption algorithm to use.

Syntax

public int getEncryptionAlgorithm();


public void setEncryptionAlgorithm(int encryptionAlgorithm);


Enumerated values:
  public final static int iesAES = 0;
  public final static int iesTripleDES = 1;
  public final static int iesXOR = 2;

Default Value

0

Remarks

This setting specifies the encryption algorithm to use when Encrypt is called. This must also be set before calling Decrypt to match the algorithm used during the initial encryption.

Possible values are:

• 0 (iesAES - default)
• 1 (iesTripleDES)
• 2 (iesXOR)

AES Notes

When EncryptionAlgorithm is set to iesAES, AES CBC with a default key size of 256 bits is used. To specify a different key size, set EncryptionKeySize.

HashAlgorithm Property (ECC Class)

The hash algorithm used for hash computation.

Syntax

public int getHashAlgorithm();


public void setHashAlgorithm(int hashAlgorithm);


Enumerated values:
  public final static int ehaSHA1 = 0;
  public final static int ehaSHA224 = 1;
  public final static int ehaSHA256 = 2;
  public final static int ehaSHA384 = 3;
  public final static int ehaSHA512 = 4;
  public final static int ehaMD2 = 5;
  public final static int ehaMD4 = 6;
  public final static int ehaMD5 = 7;
  public final static int ehaMD5SHA1 = 8;
  public final static int ehaRIPEMD160 = 9;

Default Value

2

Remarks

This property specifies the hash algorithm used for hash computation. This is only applicable when calling Sign or VerifySignature and Algorithm specifies a ECDSA key (NIST, Koblitz, or Brainpool curve). Possible values are:

When Algorithm specifies an EdDSA key, this setting is not applicable as the hash algorithm is defined by the specification as SHA-512 for Ed25519 and SHAKE-256 for Ed448.

HashEdDSA Property (ECC Class)

Whether to use HashEdDSA when signing with an Ed25519 or Ed448 key.

Syntax

public boolean isHashEdDSA();


public void setHashEdDSA(boolean hashEdDSA);

Default Value

False

Remarks

This setting specifies whether to use the HashEdDSA algorithm when signing and verifying with Ed25519 or Ed448 keys.

If set to True, the class will use the HashEdDSA algorithm (Ed25519ph or Ed448ph) when signing and verifying. When using a HashEdDSA algorithm, the input is pre-hashed and supports a single pass over the data during the signing operation.

If set to False (default), the class will use the PureEdDSA algorithm (Ed25519 or Ed448) when signing. The PureEdDSA requires two passes over the input data but provides collision resilience. The collision resilience of PureEdDSA means that even if it is feasible to compute collisions for the hash function, the algorithm is still secure.

This property is only applicable when calling Sign and Algorithm is set to Ed25519 or Ed448.

If this property is set before calling Sign, it must be set before calling VerifySignature.

HashSignature Property (ECC Class)

The hash signature.

Syntax

public byte[] getHashSignature();


public void setHashSignature(byte[] hashSignature);

Default Value

""

Remarks

This property holds the computed hash signature. This is populated after calling Sign. This must be set before calling VerifySignature.

HashValue Property (ECC Class)

The hash value of the data.

Syntax

public byte[] getHashValue();


public void setHashValue(byte[] hashValue);

Default Value

""

Remarks

This property holds the computed hash value for the specified data. This is populated when calling Sign or VerifySignature when an input file is specified by setting SetInputStream, InputFile, or InputMessage.

Pre-existing hash values may be set to this property before calling Sign or VerifySignature. If you know the hash value prior to using the class, you may specify the pre-computed hash value here.

This setting is not applicable to PureEdDSA algorithms. If Algorithm is Ed25519 or Ed448 and HashEdDSA is False (default), the PureEdDSA algorithm is used and HashValue is not applicable.

Hash Notes

The class will determine whether or not to recompute the hash based on the properties that are set. If a file is specified by SetInputStream, InputFile, or InputMessage, the hash will be recomputed when calling Sign or VerifySignature. If the HashValue property is set, the class will only sign the hash or verify the hash signature. Setting SetInputStream, InputFile, or InputMessage clears the HashValue property. Setting the HashValue property clears the input file selection.

HMACAlgorithm Property (ECC Class)

The HMAC algorithm to use during encryption.

Syntax

public int getHMACAlgorithm();


public void setHMACAlgorithm(int HMACAlgorithm);


Enumerated values:
  public final static int iesHMACSHA1 = 0;
  public final static int iesHMACSHA224 = 1;
  public final static int iesHMACSHA256 = 2;
  public final static int iesHMACSHA384 = 3;
  public final static int iesHMACSHA512 = 4;
  public final static int iesHMACRIPEMD160 = 5;

Default Value

2

Remarks

This property specifies the HMAC algorithm to use when encrypting. The HMAC algorithm is used when Encrypt and Decrypt are called to protect and verify data. Possible values are:

• 0 (iesHMACSHA1)
• 1 (iesHMACSHA224)
• 2 (iesHMACSHA256 - Default)
• 3 (iesHMACSHA384)
• 4 (iesHMACSHA512)
• 5 (iesHMACRIPEMD160)

This property is only applicable when calling Encrypt or Decrypt.

InputFile Property (ECC Class)

The file to process.

Syntax

public String getInputFile();


public void setInputFile(String inputFile);

Default Value

""

Remarks

This property specifies the file to be processed. Set this property to the full or relative path to the file which will be processed.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

• SetInputStream
• InputFile
• InputMessage

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

• SetOutputStream
• OutputFile
• OutputMessage: The output data is written to this property if no other destination is specified.

When using streams, you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.

InputMessage Property (ECC Class)

The message to process.

Syntax

public byte[] getInputMessage();


public void setInputMessage(byte[] inputMessage);

Default Value

""

Remarks

This property specifies the message to be processed.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

• SetInputStream
• InputFile
• InputMessage

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

• SetOutputStream
• OutputFile
• OutputMessage: The output data is written to this property if no other destination is specified.

When using streams, you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.

IV Property (ECC Class)

The initialization vector (IV) used when encrypting.

Syntax

public byte[] getIV();


public void setIV(byte[] IV);

Default Value

""

Remarks

This property optionally specifies an IV to be used when calling Encrypt or Decrypt. If specified, the IV is used by EncryptionAlgorithm during encryption.

If not specified, the class will create an IV filled with null bytes (zeros). Since the encryption key is only used once, the use of null bytes in the IV is considered acceptable and is a standard practice.

The length of the IV should be as follows:

This setting is not applicable when EncryptionAlgorithm is set to XOR.

KDF Property (ECC Class)

The key derivation function used during encryption and decryption.

Syntax

public String getKDF();


public void setKDF(String KDF);

Default Value

"KDF2"

Remarks

This property specifies the key derivation function (KDF) to use when encrypting and decrypting. Possible values are:

• "KDF1"
• "KDF2" (default)

The KDFHashAlgorithm specifies the hash algorithm used in conjunction with the specified KDF.

This property is only applicable when calling Encrypt or Decrypt.

KDFHashAlgorithm Property (ECC Class)

The KDF hash algorithm to use when encrypting and decrypting.

Syntax

public int getKDFHashAlgorithm();


public void setKDFHashAlgorithm(int KDFHashAlgorithm);


Enumerated values:
  public final static int iesSHA1 = 0;
  public final static int iesSHA224 = 1;
  public final static int iesSHA256 = 2;
  public final static int iesSHA384 = 3;
  public final static int iesSHA512 = 4;

Default Value

2

Remarks

This property specifies the hash algorithm to use when deriving a key using the specified KDF. Possible values are:

• 0 (iesSHA1)
• 1 (iesSHA224)
• 2 (iesSHA256)
• 3 (iesSHA384)
• 4 (iesSHA512)

This property is only applicable when calling Encrypt or Decrypt.

Key Property (ECC Class)

The ECC key.

Syntax

public ECCKey getKey();


public void setKey(ECCKey key);

Remarks

This property specifies the ECC private key. This property must be set before calling Sign or ComputeSecret.

NIST, Koblitz, and Brainpool Curve Notes

Keys for use with NIST curves (secp256r1, secp384r1, secp521r1), Koblitz curves (secp160k1, secp192k1, secp224k1, secp256k1), and Brainpool curves are made up of a number of individual parameters.

The public key consists of the following parameters:

• Rx
• Ry

The private key consists of one value:

• K

Curve25519 and Curve448 Notes

Keys for use with Curve25519 or Curve448 are made up of a private key and public key field.

XPk holds the public key.

XSk holds the private key.

Please refer to the ECCKey type for a complete list of fields.

OutputFile Property (ECC Class)

The output file when encrypting or decrypting.

Syntax

public String getOutputFile();


public void setOutputFile(String outputFile);

Default Value

""

Remarks

This property specifies the file to which the output will be written when Encrypt or Decrypt is called. This may be set to an absolute or relative path.

This property is only applicable to Encrypt and Decrypt.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

• SetInputStream
• InputFile
• InputMessage

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

• SetOutputStream
• OutputFile
• OutputMessage: The output data is written to this property if no other destination is specified.

When using streams, you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.

OutputMessage Property (ECC Class)

The output message when encrypting or decrypting.

Syntax

public byte[] getOutputMessage();

Default Value

""

Remarks

This property will be populated with the output after calling Encrypt or Decrypt if OutputFile and SetOutputStream are not set.

This property is only applicable to Encrypt and Decrypt.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

• SetInputStream
• InputFile
• InputMessage

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

• SetOutputStream
• OutputFile
• OutputMessage: The output data is written to this property if no other destination is specified.

When using streams, you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.

This property is read-only and not available at design time.

Overwrite Property (ECC Class)

Indicates whether or not the class should overwrite files.

Syntax

public boolean isOverwrite();


public void setOverwrite(boolean overwrite);

Default Value

False

Remarks

This property indicates whether or not the class will overwrite OutputFile. If Overwrite is False, an error will be thrown whenever OutputFile exists before an operation. The default value is False.

RecipientCert Property (ECC Class)

The certificate used for encryption and computing a shared secret.

Syntax

public Certificate getRecipientCert();


public void setRecipientCert(Certificate recipientCert);

Remarks

This property specifies a certificate for encryption and computing a shared secret.

This may be set instead of RecipientKey, allowing a Certificate object to be used instead of a ECCKey object. This certificate is used when calling Encrypt and ComputeSecret.

If both this property and RecipientKey are specified, RecipientKey will be used and this property will be ignored.

Please refer to the Certificate type for a complete list of fields.

RecipientKey Property (ECC Class)

The public key used to compute the shared secret.

Syntax

public ECCKey getRecipientKey();


public void setRecipientKey(ECCKey recipientKey);

Remarks

This property specifies the public key used to compute the shared secret. If RecipientCert is not specified, this must be set before calling ComputeSecret.

Please refer to the ECCKey type for a complete list of fields.

SharedSecret Property (ECC Class)

The computed shared secret.

Syntax

public byte[] getSharedSecret();

Default Value

""

Remarks

This property holds the shared secret computed by ComputeSecret.

This property is read-only.

SignerCert Property (ECC Class)

The certificate used for signature verification.

Syntax

public Certificate getSignerCert();


public void setSignerCert(Certificate signerCert);

Remarks

This property specifies a certificate for signature verification.

This may be set instead of SignerKey, allowing a Certificate object to be used instead of a ECCKey object. This certificate is used when calling VerifySignature.

If both this property and SignerKey are specified, SignerKey will be used and this property will be ignored.

Please refer to the Certificate type for a complete list of fields.

SignerKey Property (ECC Class)

The public key used to verify the signature.

Syntax

public ECCKey getSignerKey();


public void setSignerKey(ECCKey signerKey);

Remarks

This property specifies the public key used to verify the signature. This public key corresponds to the private key used when creating the signature. This must be set before calling VerifySignature.

Please refer to the ECCKey type for a complete list of fields.

UseHex Property (ECC Class)

Whether binary values are hex encoded.

Syntax

public boolean isUseHex();


public void setUseHex(boolean useHex);

Default Value

False

Remarks

This setting specifies whether various calculated values are hex encoded. If set to False (default), all data is provided as-is with no encoding.

If set to True, certain properties are hex encoded when populated for ease of display, transport, and storage.

Compute Secret Notes

This property specifies whether SharedSecret is hex encoded when ComputeSecret is called.

Sign and Verify Notes

This property specifies whether HashValue and HashSignature are hex encoded.

If set to True, when Sign is called the class will compute the hash for the specified file and populate HashValue with the hex encoded hash value. It will then create the hash signature and populate HashSignature with the hex encoded hash signature value. If HashValue is specified directly, it must be a hex encoded value.

If set to True, when VerifySignature is called the class will compute the hash value for the specified file and populate HashValue with the hex encoded hash value. It will then hex decode HashSignature and verify the signature. HashSignature must hold a hex encoded value. If HashValue is specified directly, it must be a hex encoded value.

Encrypt and Decrypt Notes

If set to True, when Encrypt is called the class will perform the encryption as normal and then hex encode the output. OutputMessage or OutputFile will hold hex encoded data.

If set to True, when Decrypt is called the class will expect InputMessage or InputFile to hold hex encoded data. The class will then hex decode the data and perform decryption as normal.

ComputeSecret Method (ECC Class)

Computes a shared secret.

Syntax

public void computeSecret();

Remarks

This method computes a shared secret using Elliptic Curve Diffie Hellman (ECDH).

When this method is called, the class will use the public key specified by RecipientKey (or RecipientCert) and the private key specified by Key to compute a shared secret, or secret agreement. The ComputeSecretKDF property specifies the Hash or HMAC algorithm that is applied to the raw secret. The resulting value is held by SharedSecret. The following properties are applicable when calling this method:

• Key (required)
• RecipientKey or RecipientCert (required)
• ComputeSecretKDF (optional)

See ComputeSecretKDF for details on advanced settings that may be applicable for the chosen algorithm.

Keys created with the Ed25519 and Ed448 algorithms are not supported when calling this method.

Compute Secret Example

//Create a key for Party 1 Ecc ecc1 = new Ecc(); ecc1.CreateKey("X25519"); string ecc1_priv = ecc1.Key.PrivateKey; string ecc1_pub = ecc1.Key.PublicKey; //Create a key for Party 2 Ecc ecc2 = new Ecc(); ecc2.CreateKey("X25519"); string ecc2_priv = ecc2.Key.PrivateKey; string ecc2_pub = ecc2.Key.PublicKey; //Note: the public keys must be exchanged between parties by some mechanism //Create the shared secret on Party 1 ecc1.Reset(); ecc1.Key.PrivateKey = ecc1_priv; //Private key of this party ecc1.RecipientKey.PublicKey = ecc2_pub; //Public key of other party ecc1.UseHex = true; //Hex encodes the shared secret bytes for easier display/storage ecc1.ComputeSecret(); Console.WriteLine(ecc1.SharedSecret); //Create the shared secret on Party 2 ecc2.Reset(); ecc2.Key.PrivateKey = ecc2_priv; //Private key of this party ecc2.RecipientKey.PublicKey = ecc1_pub; //Public key of other party ecc2.UseHex = true; //Hex encodes the shared secret bytes for easier display/storage ecc2.ComputeSecret(); Console.WriteLine(ecc2.SharedSecret); //This will match the shared secret created by ecc1.

Config Method (ECC Class)

This method sets or retrieves a configuration setting.

Syntax

public String config(String configurationString);

Remarks

Config is a generic method available in every class. It is used to set and retrieve configuration settings for the class.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

CreateKey Method (ECC Class)

Creates a new key.

Syntax

public void createKey(String keyAlgorithm);

Remarks

CreateKey creates a new public and private key.

When this method is called, Key is populated with the generated key. The PublicKey and PrivateKey fields hold the PEM formatted public and private key for ease of use. This is helpful for storing or transporting keys more easily.

The KeyAlgorithm parameter specifies the algorithm for which the key is intended to be used. Possible values are:

NIST, Koblitz, and Brainpool Curve Notes

Keys for use with NIST curves (secp256r1, secp384r1, secp521r1), Koblitz curves (secp160k1, secp192k1, secp224k1, secp256k1), and Brainpool curves are made up of a number of individual parameters.

The public key consists of the following parameters:

• Rx
• Ry

The private key consists of one value:

• K

Curve25519 and Curve448 Notes

Keys for use with Curve25519 or Curve448 are made up of a private key and public key field.

XPk holds the public key.

XSk holds the private key.

Create Key Example (secp256r1 - PEM)

//Create a key using secp256r1 Ecc ecc = new Ecc(); ecc.CreateKey("secp256r1"); Console.WriteLine(ecc.Key.Algorithm); //outputs enum value "eaSecp256r1" string privKey = ecc.Key.PrivateKey; //PEM formatted key string pubKey = ecc.Key.PublicKey; //PEM formatted key //Load the saved key ecc.Reset(); ecc.Key.PublicKey = pubKey; ecc.Key.PrivateKey = privKey; Console.WriteLine(ecc.Key.Algorithm); //outputs enum value "eaSecp256r1"

Create Key Example (secp256r1 - Raw Key Params)

//Create a key using secp256r1 and store/load the key using the individual params Ecc ecc = new Ecc(); ecc.CreateKey("secp256r1"); Console.WriteLine(ecc.Key.Algorithm); //outputs enum value "eaSecp256r1" byte[] K = ecc.Key.KB; //Private key param byte[] Rx = ecc.Key.RxB; //Public key param byte[] Ry = ecc.Key.RyB; //Public key param //Load the saved key ecc.Reset(); ecc.Key.Algorithm = ECAlgorithms.eaSecp256r1; //This MUST be set manually when using key params directly ecc.Key.KB = K; ecc.Key.RxB = Rx; ecc.Key.RyB = Ry; Console.WriteLine(ecc.Key.Algorithm); //outputs enum value "eaSecp256r1"

Create Key Example (Ed25519 - PEM)

//Create a key using Ed25519 Ecc ecc = new Ecc(); ecc.CreateKey("Ed25519"); Console.WriteLine(ecc.Key.Algorithm); //outputs enum value "eaEd25519" string privKey = ecc.Key.PrivateKey; //PEM formatted key string pubKey = ecc.Key.PublicKey; //PEM formatted key //Load the saved key ecc.Reset(); ecc.Key.PublicKey = pubKey; ecc.Key.PrivateKey = privKey; Console.WriteLine(ecc.Key.Algorithm); //outputs enum value "eaEd25519"

Create Key Example (Ed25519 - Raw Key Params)

//Create a key using Ed25519 and store/load the key using the individual params Ecc ecc = new Ecc(); ecc.CreateKey("Ed25519"); Console.WriteLine(ecc.Key.Algorithm); //outputs enum value "eaEd25519" byte[] XPk = ecc.Key.XPkB; //Public key data byte[] XSk = ecc.Key.XSkB; //Secret key data //Load the saved key ecc.Reset(); ecc.Key.Algorithm = ECAlgorithms.eaEd25519; //This MUST be set manually when using key params directly ecc.Key.XPkB = XPk; ecc.Key.XSkB = XSk; Console.WriteLine(ecc.Key.Algorithm); //outputs enum value "eaEd25519"

Decrypt Method (ECC Class)

Decrypted the specified data.

Syntax

public void decrypt();

Remarks

Decrypt decrypts the specified data with the ECDSA private key specified in Key.

Decryption is performed using ECIES which requires an ECDSA key. Key must contain an ECDSA key. Algorithm is used to determine the eligibility of the key for this operation. Supported algorithms for encryption are:

• NIST Curves (secp256r1, secp384r1, secp521r1)
• Koblitz Curves (secp160k1, secp192k1, secp224k1, secp256k1)
• Brainpool Curves

See CreateKey for details about key creation and algorithms.

When this method is called, the class will decrypt the specified data using ECIES and the decrypted data will be output. If the input data was originally hex encoded, set UseHex to True.

The following properties are applicable when calling this method:

• EncryptionAlgorithm
• HMACAlgorithm
• HMACOptionalInfo
• HMACKeySize
• IV
• KDF
• KDFHashAlgorithm
• KDFOptionalInfo
• UseHex

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

• SetInputStream
• InputFile
• InputMessage

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

• SetOutputStream
• OutputFile
• OutputMessage: The output data is written to this property if no other destination is specified.

When using streams, you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.

Encrypt and Decrypt Example

//Create an ECDSA key on Party 2 Ecc ecc2 = new Ecc(); ecc2.CreateKey("secp256r1"); string ecc2_priv = ecc2.Key.PrivateKey; string ecc2_pub = ecc2.Key.PublicKey; //Transmit public key to Party 1 //Encrypt the message on Party 1 using public key from Party 2 Ecc ecc1 = new Ecc(); ecc1.InputMessage = "hello ecc"; ecc1.RecipientKey.PublicKey = ecc2_pub; ecc1.UseHex = true; ecc1.Encrypt(); string encryptedMessage = ecc1.OutputMessage; //Transmit the encrypted message to Party 2 //Decrypt the message using the private key for Party 2 ecc2.Key.PrivateKey = ecc2_priv; ecc2.InputMessage = encryptedMessage; ecc2.UseHex = true; ecc2.Decrypt(); Console.WriteLine(ecc2.OutputMessage);

Encrypt and Decrypt Example (AES with IV)

//Create an ECDSA key on Party 2 Ecc ecc2 = new Ecc(); ecc2.CreateKey("secp256r1"); string ecc2_priv = ecc2.Key.PrivateKey; string ecc2_pub = ecc2.Key.PublicKey; //Transmit public key to Party 1 //Encrypt the message on Party 1 using public key from Party 2 Ecc ecc1 = new Ecc(); //Use an IV (16 bytes for AES) - In a real environment this should be random byte[] IV = new byte[] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F }; ecc1.EncryptionAlgorithm = EccEncryptionAlgorithms.iesAES; ecc1.IVB = IV; ecc1.InputMessage = "hello ecc"; ecc1.RecipientKey.PublicKey = ecc2_pub; ecc1.UseHex = true; ecc1.Encrypt(); string encryptedMessage = ecc1.OutputMessage; //Transmit the encrypted message and the IV to Party 2 //Decrypt the message using the private key for Party 2 and the IV ecc2.EncryptionAlgorithm = EccEncryptionAlgorithms.iesAES; ecc2.IVB = IV; ecc2.Key.PrivateKey = ecc2_priv; ecc2.InputMessage = encryptedMessage; ecc2.UseHex = true; ecc2.Decrypt(); Console.WriteLine(ecc2.OutputMessage);

Encrypt and Decrypt Example (XOR Encryption Algorithm)

//Create an ECDSA key on Party 2 Ecc ecc2 = new Ecc(); ecc2.CreateKey("secp256r1"); string ecc2_priv = ecc2.Key.PrivateKey; string ecc2_pub = ecc2.Key.PublicKey; //Transmit public key to Party 1 //Encrypt the message on Party 1 using public key from Party 2 Ecc ecc1 = new Ecc(); ecc1.EncryptionAlgorithm = EccEncryptionAlgorithms.iesXOR; ecc1.InputMessage = "hello ecc"; ecc1.RecipientKey.PublicKey = ecc2_pub; ecc1.UseHex = true; ecc1.Encrypt(); string encryptedMessage = ecc1.OutputMessage; //Transmit the encrypted message to Party 2 //Decrypt the message using the private key for Party 2 ecc2.EncryptionAlgorithm = EccEncryptionAlgorithms.iesXOR; ecc2.Key.PrivateKey = ecc2_priv; ecc2.InputMessage = encryptedMessage; ecc2.UseHex = true; ecc2.Decrypt(); Console.WriteLine(ecc2.OutputMessage);

Encrypt and Decrypt Example (KDF Options)

//Create an ECDSA key on Party 2 Ecc ecc2 = new Ecc(); ecc2.CreateKey("secp256r1"); string ecc2_priv = ecc2.Key.PrivateKey; string ecc2_pub = ecc2.Key.PublicKey; //Transmit public key to Party 1 //Encrypt the message on Party 1 using public key from Party 2 Ecc ecc1 = new Ecc(); ecc1.KDF = "KDF1"; //Use KDF1 ecc1.KDFHashAlgorithm = EccKDFHashAlgorithms.iesSHA1; ecc1.Config("KDFOptionalInfo=202122232425262728292a2b2c2d2e2f"); //Hex encoded string ecc1.InputMessage = "hello ecc"; ecc1.RecipientKey.PublicKey = ecc2_pub; ecc1.UseHex = true; ecc1.Encrypt(); string encryptedMessage = ecc1.OutputMessage; //Transmit the encrypted message to Party 2 //Decrypt the message using the private key for Party 2 ecc2.KDF = "KDF1"; ecc2.KDFHashAlgorithm = EccKDFHashAlgorithms.iesSHA1; ecc2.Config("KDFOptionalInfo=202122232425262728292a2b2c2d2e2f"); ecc2.Key.PrivateKey = ecc2_priv; ecc2.InputMessage = encryptedMessage; ecc2.UseHex = true; ecc2.Decrypt(); Console.WriteLine(ecc2.OutputMessage);

Encrypt Method (ECC Class)

Encrypts the specified data.

Syntax

public void encrypt();

Remarks

Encrypt encrypts the specified data with the ECDSA public key specified in RecipientKey.

Encryption is performed using ECIES which requires an ECDSA key. RecipientKey must contain an ECDSA key. Algorithm is used to determine the eligibility of the key for this operation. Supported algorithms for encryption are:

• NIST Curves (secp256r1, secp384r1, secp521r1)
• Koblitz Curves (secp160k1, secp192k1, secp224k1, secp256k1)
• Brainpool Curves

See CreateKey for details about key creation and algorithms.

When this method is called, the class will encrypt the specified data using ECIES and the encrypted data will be output. To hex encode the output, set UseHex to True.

The following properties are applicable when calling this method:

• EncryptionAlgorithm
• HMACAlgorithm
• HMACOptionalInfo
• HMACKeySize
• IV
• KDF
• KDFHashAlgorithm
• KDFOptionalInfo
• UseHex

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

• SetInputStream
• InputFile
• InputMessage

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

• SetOutputStream
• OutputFile
• OutputMessage: The output data is written to this property if no other destination is specified.

When using streams, you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.

Encrypt and Decrypt Example

//Create an ECDSA key on Party 2 Ecc ecc2 = new Ecc(); ecc2.CreateKey("secp256r1"); string ecc2_priv = ecc2.Key.PrivateKey; string ecc2_pub = ecc2.Key.PublicKey; //Transmit public key to Party 1 //Encrypt the message on Party 1 using public key from Party 2 Ecc ecc1 = new Ecc(); ecc1.InputMessage = "hello ecc"; ecc1.RecipientKey.PublicKey = ecc2_pub; ecc1.UseHex = true; ecc1.Encrypt(); string encryptedMessage = ecc1.OutputMessage; //Transmit the encrypted message to Party 2 //Decrypt the message using the private key for Party 2 ecc2.Key.PrivateKey = ecc2_priv; ecc2.InputMessage = encryptedMessage; ecc2.UseHex = true; ecc2.Decrypt(); Console.WriteLine(ecc2.OutputMessage);

Encrypt and Decrypt Example (AES with IV)

//Create an ECDSA key on Party 2 Ecc ecc2 = new Ecc(); ecc2.CreateKey("secp256r1"); string ecc2_priv = ecc2.Key.PrivateKey; string ecc2_pub = ecc2.Key.PublicKey; //Transmit public key to Party 1 //Encrypt the message on Party 1 using public key from Party 2 Ecc ecc1 = new Ecc(); //Use an IV (16 bytes for AES) - In a real environment this should be random byte[] IV = new byte[] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F }; ecc1.EncryptionAlgorithm = EccEncryptionAlgorithms.iesAES; ecc1.IVB = IV; ecc1.InputMessage = "hello ecc"; ecc1.RecipientKey.PublicKey = ecc2_pub; ecc1.UseHex = true; ecc1.Encrypt(); string encryptedMessage = ecc1.OutputMessage; //Transmit the encrypted message and the IV to Party 2 //Decrypt the message using the private key for Party 2 and the IV ecc2.EncryptionAlgorithm = EccEncryptionAlgorithms.iesAES; ecc2.IVB = IV; ecc2.Key.PrivateKey = ecc2_priv; ecc2.InputMessage = encryptedMessage; ecc2.UseHex = true; ecc2.Decrypt(); Console.WriteLine(ecc2.OutputMessage);

Encrypt and Decrypt Example (XOR Encryption Algorithm)

//Create an ECDSA key on Party 2 Ecc ecc2 = new Ecc(); ecc2.CreateKey("secp256r1"); string ecc2_priv = ecc2.Key.PrivateKey; string ecc2_pub = ecc2.Key.PublicKey; //Transmit public key to Party 1 //Encrypt the message on Party 1 using public key from Party 2 Ecc ecc1 = new Ecc(); ecc1.EncryptionAlgorithm = EccEncryptionAlgorithms.iesXOR; ecc1.InputMessage = "hello ecc"; ecc1.RecipientKey.PublicKey = ecc2_pub; ecc1.UseHex = true; ecc1.Encrypt(); string encryptedMessage = ecc1.OutputMessage; //Transmit the encrypted message to Party 2 //Decrypt the message using the private key for Party 2 ecc2.EncryptionAlgorithm = EccEncryptionAlgorithms.iesXOR; ecc2.Key.PrivateKey = ecc2_priv; ecc2.InputMessage = encryptedMessage; ecc2.UseHex = true; ecc2.Decrypt(); Console.WriteLine(ecc2.OutputMessage);

Encrypt and Decrypt Example (KDF Options)

//Create an ECDSA key on Party 2 Ecc ecc2 = new Ecc(); ecc2.CreateKey("secp256r1"); string ecc2_priv = ecc2.Key.PrivateKey; string ecc2_pub = ecc2.Key.PublicKey; //Transmit public key to Party 1 //Encrypt the message on Party 1 using public key from Party 2 Ecc ecc1 = new Ecc(); ecc1.KDF = "KDF1"; //Use KDF1 ecc1.KDFHashAlgorithm = EccKDFHashAlgorithms.iesSHA1; ecc1.Config("KDFOptionalInfo=202122232425262728292a2b2c2d2e2f"); //Hex encoded string ecc1.InputMessage = "hello ecc"; ecc1.RecipientKey.PublicKey = ecc2_pub; ecc1.UseHex = true; ecc1.Encrypt(); string encryptedMessage = ecc1.OutputMessage; //Transmit the encrypted message to Party 2 //Decrypt the message using the private key for Party 2 ecc2.KDF = "KDF1"; ecc2.KDFHashAlgorithm = EccKDFHashAlgorithms.iesSHA1; ecc2.Config("KDFOptionalInfo=202122232425262728292a2b2c2d2e2f"); ecc2.Key.PrivateKey = ecc2_priv; ecc2.InputMessage = encryptedMessage; ecc2.UseHex = true; ecc2.Decrypt(); Console.WriteLine(ecc2.OutputMessage);

Reset Method (ECC Class)

Resets the class.

Syntax

public void reset();

Remarks

When called, the class will reset all of its properties to their default values.

SetInputStream Method (ECC Class)

Sets the stream from which the class will read data to encrypt or decrypt.

Syntax

public void setInputStream(java.io.InputStream inputStream);

Remarks

This method sets the stream from which the class will read data to encrypt or decrypt.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

• SetInputStream
• InputFile
• InputMessage

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

• SetOutputStream
• OutputFile
• OutputMessage: The output data is written to this property if no other destination is specified.

When using streams, you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.

SetOutputStream Method (ECC Class)

Sets the stream to which the class will write encrypted or decrypted data.

Syntax

public void setOutputStream(java.io.OutputStream outputStream);

Remarks

This method sets the stream to which the class will write encrypted or decrypted data.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

• SetInputStream
• InputFile
• InputMessage

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

• SetOutputStream
• OutputFile
• OutputMessage: The output data is written to this property if no other destination is specified.

When using streams, you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.

Sign Method (ECC Class)

Creates a hash signature using ECDSA or EdDSA.

Syntax

public void sign();

Remarks

Sign will create a hash signature using ECDSA or EdDSA. The class will use the key specified by Key to hash the input data and sign the resulting hash.

Key must contain a private key created with a valid ECDSA or EdDSA algorithm. Algorithm is used to determine the eligibility of the key for this operation. Supported algorithms for signing are:

• NIST Curves (secp256r1, secp384r1, secp521r1)
• Koblitz Curves (secp160k1, secp192k1, secp224k1, secp256k1)
• Brainpool Curves
• Ed25519 and Ed448

See CreateKey for details about key creation and algorithms.

When this method is called, data will be read from the stream set by SetInputStream, InputFile, or InputMessage.

The hash to be signed will be computed using the specified HashAlgorithm. The computed hash is stored in the HashValue property. The signed hash is stored in the HashSignature property.

To sign a hash without first computing it, set HashValue to a previously computed hash for the input data. Note: HashValue is not applicable when signing with a PureEdDSA algorithm such as Ed25519 or Ed448.

The Progress event will fire with updates for the hash computation progress only. The hash signature creation process is quick and does not require progress updates.

After calling Sign, the public key must be sent to the recipient along with HashSignature and the original input data so the other party may perform signature verification.

The following properties are applicable when calling this method:

• Key (required)
• HashAlgorithm (applicable to ECDSA only)
• HashEdDSA (applicable to EdDSA only)
• HashValue (not applicable to PureEdDSA)
• UseHex

The following properties are populated after calling this method:

• HashValue
• HashSignature

EdDSA Notes

When the Algorithm is Ed25519 or Ed448, the following additional parameters are applicable:

• HashEdDSA
• EdDSAContext

EdDSA keys can be used with a PureEdDSA algorithm (Ed25519/Ed448) or a HashEdDSA (Ed25519ph, Ed448ph) algorithm. This is controlled by the HashEdDSA property. By default, the class uses the PureEdDSA algorithm.

The PureEdDSA algorithm requires two passes over the input data but provides collision resilience. The collision resilience of PureEdDSA means that even if it is feasible to compute collisions for the hash function, the algorithm is still secure. When using PureEdDSA, HashValue is not applicable.

When using a HashEdDSA algorithm, the input is pre-hashed and supports a single pass over the data during the signing operation. To enable HashEdDSA, set HashEdDSA to True.

To specify context data when using Ed25519 or Ed448, set EdDSAContext.

Sign And Verify Example (ECDSA)

//Create an ECDSA key on Party 1 Ecc ecc1 = new Ecc(); ecc1.CreateKey("secp256r1"); string ecc1_priv = ecc1.Key.PrivateKey; string ecc1_pub = ecc1.Key.PublicKey; //Sign the data on Party 1 string originalData = "hello ecc"; ecc1.Reset(); ecc1.Key.PrivateKey = ecc1_priv; ecc1.InputMessage = originalData; ecc1.UseHex = true; //Hex encode the hash signature for ease of use. ecc1.Sign(); string hashSignature = ecc1.HashSignature; //Transmit the hash signature, public key, and original data to Party 2 //Verify the data on Party 2 Ecc ecc2 = new Ecc(); ecc2.SignerKey.PublicKey = ecc1_pub; ecc2.InputMessage = originalData; ecc2.HashSignature = hashSignature; ecc2.UseHex = true; //Decode the hex encoded hash signature bool isVerified = ecc2.VerifySignature();

Sign And Verify Example (EdDSA - PureEdDSA)

//Create an EdDSA key on Party 1 Ecc ecc1 = new Ecc(); ecc1.CreateKey("ed25519"); string ecc1_priv = ecc1.Key.PrivateKey; string ecc1_pub = ecc1.Key.PublicKey; //Sign the data on Party 1 string originalData = "hello ecc"; ecc1.Reset(); ecc1.Key.PrivateKey = ecc1_priv; ecc1.InputMessage = originalData; ecc1.UseHex = true; //Hex encode the hash signature for ease of use. ecc1.Sign(); string hashSignature = ecc1.HashSignature; //Transmit the hash signature, public key, and original data to Party 2 //Verify the data on Party 2 Ecc ecc2 = new Ecc(); ecc2.SignerKey.PublicKey = ecc1_pub; ecc2.InputMessage = originalData; ecc2.HashSignature = hashSignature; ecc2.UseHex = true; //Decode the hex encoded hash signature bool isVerified = ecc2.VerifySignature();

Sign And Verify Example (EdDSA - HashEdDSA)

//Create an EdDSA key on Party 1 Ecc ecc1 = new Ecc(); ecc1.CreateKey("ed25519"); string ecc1_priv = ecc1.Key.PrivateKey; string ecc1_pub = ecc1.Key.PublicKey; //Sign the data on Party 1 string originalData = "hello ecc"; ecc1.Reset(); ecc1.Key.PrivateKey = ecc1_priv; ecc1.InputMessage = originalData; ecc1.UseHex = true; //Hex encode the hash signature for ease of use. ecc1.HashEdDSA = true; //Use "ed25519ph" ecc1.Sign(); string hashSignature = ecc1.HashSignature; //Transmit the hash signature, public key, and original data to Party 2 //Verify the data on Party 2 Ecc ecc2 = new Ecc(); ecc2.SignerKey.PublicKey = ecc1_pub; ecc2.InputMessage = originalData; ecc2.HashSignature = hashSignature; ecc2.HashEdDSA = true; ecc2.UseHex = true; //Decode the hex encoded hash signature bool isVerified = ecc2.VerifySignature();

VerifySignature Method (ECC Class)

Verifies the signature for the specified data.

Syntax

public boolean verifySignature();

Remarks

VerifySignature will verify a hash signature and return True if successful or False otherwise.

Before calling this method, specify the input file by setting SetInputStream, InputFile, or InputMessage.

A public key and the hash signature are required to perform the signature verification. Specify the public key in SignerKey. Specify the hash signature in HashSignature.

When this method is called, the class will compute the hash for the specified file and populate HashValue. It will verify the signature using the specified SignerKey and HashSignature.

To verify the hash signature without first computing the hash, simply specify HashValue before calling this method. Note: HashValue is not applicable when the message was signed with a PureEdDSA algorithm such as Ed25519 or Ed448.

The Progress event will fire with updates for the hash computation progress only. The hash signature verification process is quick and does not require progress updates.

The following properties are applicable when calling this method:

• HashSignature (required)
• SignerKey (required)
• EdDSAContext (applicable to EdDSA only)
• HashAlgorithm (applicable to ECDSA only)
• HashEdDSA (applicable to EdDSA only)
• HashValue (not applicable to PureEdDSA)
• UseHex

Sign And Verify Example (ECDSA)

//Create an ECDSA key on Party 1 Ecc ecc1 = new Ecc(); ecc1.CreateKey("secp256r1"); string ecc1_priv = ecc1.Key.PrivateKey; string ecc1_pub = ecc1.Key.PublicKey; //Sign the data on Party 1 string originalData = "hello ecc"; ecc1.Reset(); ecc1.Key.PrivateKey = ecc1_priv; ecc1.InputMessage = originalData; ecc1.UseHex = true; //Hex encode the hash signature for ease of use. ecc1.Sign(); string hashSignature = ecc1.HashSignature; //Transmit the hash signature, public key, and original data to Party 2 //Verify the data on Party 2 Ecc ecc2 = new Ecc(); ecc2.SignerKey.PublicKey = ecc1_pub; ecc2.InputMessage = originalData; ecc2.HashSignature = hashSignature; ecc2.UseHex = true; //Decode the hex encoded hash signature bool isVerified = ecc2.VerifySignature();

Sign And Verify Example (EdDSA - PureEdDSA)

//Create an EdDSA key on Party 1 Ecc ecc1 = new Ecc(); ecc1.CreateKey("ed25519"); string ecc1_priv = ecc1.Key.PrivateKey; string ecc1_pub = ecc1.Key.PublicKey; //Sign the data on Party 1 string originalData = "hello ecc"; ecc1.Reset(); ecc1.Key.PrivateKey = ecc1_priv; ecc1.InputMessage = originalData; ecc1.UseHex = true; //Hex encode the hash signature for ease of use. ecc1.Sign(); string hashSignature = ecc1.HashSignature; //Transmit the hash signature, public key, and original data to Party 2 //Verify the data on Party 2 Ecc ecc2 = new Ecc(); ecc2.SignerKey.PublicKey = ecc1_pub; ecc2.InputMessage = originalData; ecc2.HashSignature = hashSignature; ecc2.UseHex = true; //Decode the hex encoded hash signature bool isVerified = ecc2.VerifySignature();

Sign And Verify Example (EdDSA - HashEdDSA)

//Create an EdDSA key on Party 1 Ecc ecc1 = new Ecc(); ecc1.CreateKey("ed25519"); string ecc1_priv = ecc1.Key.PrivateKey; string ecc1_pub = ecc1.Key.PublicKey; //Sign the data on Party 1 string originalData = "hello ecc"; ecc1.Reset(); ecc1.Key.PrivateKey = ecc1_priv; ecc1.InputMessage = originalData; ecc1.UseHex = true; //Hex encode the hash signature for ease of use. ecc1.HashEdDSA = true; //Use "ed25519ph" ecc1.Sign(); string hashSignature = ecc1.HashSignature; //Transmit the hash signature, public key, and original data to Party 2 //Verify the data on Party 2 Ecc ecc2 = new Ecc(); ecc2.SignerKey.PublicKey = ecc1_pub; ecc2.InputMessage = originalData; ecc2.HashSignature = hashSignature; ecc2.HashEdDSA = true; ecc2.UseHex = true; //Decode the hex encoded hash signature bool isVerified = ecc2.VerifySignature();

Error Event (ECC Class)

This event is fired for information about errors during data delivery.

Syntax

public class DefaultECCEventListener implements ECCEventListener {
  ...
  public void error(ECCErrorEvent e) {}
  ...
}

public class ECCErrorEvent {
  public int errorCode;
  public String description;
}

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the class throws an exception.

ErrorCode contains an error code and Description contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

Progress Event (ECC Class)

Fired as progress is made.

Syntax

public class DefaultECCEventListener implements ECCEventListener {
  ...
  public void progress(ECCProgressEvent e) {}
  ...
}

public class ECCProgressEvent {
  public long bytesProcessed;
  public int percentProcessed;
}

Remarks

This event is fired automatically as data is processed by the class.

The PercentProcessed parameter indicates the current status of the operation.

The BytesProcessed parameter holds the total number of bytes processed so far.

Certificate Type

This is the digital certificate being used.

Remarks

This type describes the current digital certificate. The certificate may be a public or private key. The fields are used to identify or select certificates.

Fields

Constructors

public Certificate();

Creates a Certificate instance whose properties can be set. This is useful for use with CERTMGR when generating new certificates.

public Certificate( certificateFile);

Opens CertificateFile and reads out the contents as an X509 public key.

public Certificate( encoded);

Parses Encoded as an X509 public key.

public Certificate( storeType,  store,  storePassword,  subject);

CertStoreType identifies the type of certificate store to use. See StoreType for descriptions of the different certificate stores. Store is a file containing the certificate store. StorePassword is the password used to protect the store. After the store has been successfully opened, the class will attempt to find the certificate identified by Subject . This can be either a complete or a substring match of the X509 certificate's subject Distinguished Name (DN). The Subject parameter can also take an MD5, SHA1, or SHA256 thumbprint of the certificate to load in a "Thumbprint=value" format.

public Certificate( storeType,  store,  storePassword,  subject,  configurationString);

CertStoreType identifies the type of certificate store to use. See StoreType for descriptions of the different certificate stores. Store is a file containing the certificate store. StorePassword is the password used to protect the store. ConfigurationString is a newline separated list of name-value pairs that may be used to modify the default behavior. Possible values include "PersistPFXKey", which shows whether or not the PFX key is persisted after performing operations with the private key. This correlates to the PKCS12_NO_PERSIST_KEY CyrptoAPI option. The default value is True (the key is persisted). "Thumbprint" - an MD5, SHA1, or SHA256 thumbprint of the certificate to load. When specified, this value is used to select the certificate in the store. This is applicable to cstUser, cstMachine, cstPublicKeyFile, and cstPFXFile store types. "UseInternalSecurityAPI" shows whether the platform (default) or the internal security API is used when performing certificate-related operations. After the store has been successfully opened, the class will attempt to find the certificate identified by Subject . This can be either a complete or a substring match of the X509 certificate's subject Distinguished Name (DN). The Subject parameter can also take an MD5, SHA1, or SHA256 thumbprint of the certificate to load in a "Thumbprint=value" format.

public Certificate( storeType,  store,  storePassword,  encoded);

CertStoreType identifies the type of certificate store to use. See StoreType for descriptions of the different certificate stores. Store is a file containing the certificate store. StorePassword is the password used to protect the store. After the store has been successfully opened, the class will load Encoded as an X509 certificate and search the opened store for a corresponding private key.

public Certificate( storeType,  store,  storePassword,  subject);

CertStoreType identifies the type of certificate store to use. See StoreType for descriptions of the different certificate stores. Store is a string (binary- or base64-encoded) containing the certificate data. StorePassword is the password used to protect the store. After the store has been successfully opened, the class will attempt to find the certificate identified by Subject . This can be either a complete or a substring match of the X509 certificate's subject Distinguished Name (DN). The Subject parameter can also take an MD5, SHA1, or SHA256 thumbprint of the certificate to load in a "Thumbprint=value" format.

public Certificate( storeType,  store,  storePassword,  subject,  configurationString);

CertStoreType identifies the type of certificate store to use. See StoreType for descriptions of the different certificate stores. Store is a string (binary- or base64-encoded) containing the certificate data. StorePassword is the password used to protect the store. After the store has been successfully opened, the class will attempt to find the certificate identified by Subject . This can be either a complete or a substring match of the X509 certificate's subject Distinguished Name (DN). The Subject parameter can also take an MD5, SHA1, or SHA256 thumbprint of the certificate to load in a "Thumbprint=value" format.

public Certificate( storeType,  store,  storePassword,  encoded);

CertStoreType identifies the type of certificate store to use. See StoreType for descriptions of the different certificate stores. Store is a string (binary- or base64-encoded) containing the certificate store. StorePassword is the password used to protect the store. After the store has been successfully opened, the class will load Encoded as an X509 certificate and search the opened store for a corresponding private key.

ECCKey Type

Contains the parameters for the ECC algorithm.

Remarks

This type is made up of fields that represent the private and public key parameters used by the ECC operations. The PrivateKey and PublicKey parameters hold a PEM formatted value for easy transport and storage of keys.

NIST, Koblitz, and Brainpool Curve Notes

Keys for use with NIST curves (secp256r1, secp384r1, secp521r1), Koblitz curves (secp160k1, secp192k1, secp224k1, secp256k1), and Brainpool curves are made up of a number of individual parameters.

The public key consists of the following parameters:

• Rx
• Ry

The private key consists of one value:

• K

Curve25519 and Curve448 Notes

Keys for use with Curve25519 or Curve448 are made up of a private key and public key field.

XPk holds the public key.

XSk holds the private key.

Fields

Constructors

public ECCKey();

The default constructor creates a new ECCKey instance but does not assign a public or private key.

public ECCKey( rx,  ry,  algorithm);

The public key constructor assigns an existing public key.

public ECCKey( K,  rx,  ry,  algorithm);

The private key constructor assigns an existing private key.

Config Settings (ECC Class)

The class accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

ECC Config Settings

Base Config Settings

Trappable Errors (ECC Class)

ECC Errors