sign Method
Creates a hash signature using ECDSA or EdDSA.
Syntax
def sign() -> None: ...
Remarks
on_sign will create a hash signature using ECDSA or EdDSA. The class will use the key specified by key to has the input data and sign the resulting hash.
key must contain a private key created with a valid ECDSA or EdDSA algorithm. key_algorithm is used to determine the eligibility of the key for this operation. Supported algorithms for signing are:
- secp256r1
- secp384r1
- secp521r1
- ed25519
- ed448
See create_key for details about key creation and algorithms.
When this method is called data will be read from the input_file or input_message.
The hash to be signed will be computed using the specified hash_algorithm. The computed hash is stored in the hash_value property. The signed hash is stored in the hash_signature property.
To sign as hash without first computing it set hash_value to a previously computed hash for the input data. Note: hash_value is not applicable when signing with a PureEdDSA algorithm such as "ed25519" or "ed448".
The on_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 on_sign the public key must be sent to the recipient along with hash_signature and original input data so the other party may perform signature verification.
The following properties are applicable when calling this method:
- key (required)
- hash_algorithm (applicable to secp256r1, secp384r1, and secp521r1 only)
- hash_ed_dsa (applicable to ed25519 and ed448 only)
- hash_value (not applicable to PureEdDSA)
- use_hex
The following properties are populated after calling this method:
EdDSA Notes
When the key_algorithm is ed25519 or ed448 the following additional parameters are applicable:
EdDSA keys can be used with a PureEdDSA algorithm (ed25519/ed448) or as HashEdDSA (ed25519ph, ed448ph) algorithm. This is controlled by the hash_ed_dsa 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 even if it is feasible to compute collisions for the hash function, the algorithm is still secure. When using PureEdDSA hash_value 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 hash_ed_dsa 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 part 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 part 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 part 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();