IPWorks Encrypt 2020 Android Edition

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JWE Component

Properties   Methods   Events   Configuration Settings   Errors  

Create, Encrypt and Decrypt JSON Web Encryption (JWE) messages.

Syntax

IPWorksEncrypt.Jwe

Remarks

The JWE component supports encrypting and decrypting JSON Web Encryption (JWE) messages.

Specify any payload via input properties and use Encrypt to create a JWE message using a variety of algorithms including ECDH, RSA, and AES. Use Decrypt to decrypt the payload of any received JWE message. The following algorithms are supported:

  • RSA1_5
  • RSA-OAEP
  • RSA-OAEP-256
  • A128KW
  • A192KW
  • A256KW
  • dir
  • ECDH-ES
  • ECDH-ES+A128KW
  • ECDH-ES+A192KW
  • ECDH-ES+A256KW
  • A128GCMKW
  • A192GCMKW
  • A256GCMKW
  • PBES2-HS256+A128KW
  • PBES2-HS384+A192KW
  • PBES2-HS512+A256KW

See EncryptionAlgorithm for more details about supported algorithms.

Encrypting

The Encrypt method may be used to encrypt a payload with a variety of algorithms. JSON Web Encryption (JWE) is performed by first generating a random key used to encrypt the content. The content encryption key is used to encrypt the content using the algorithm specified by ContentEncryptionAlgorithm. The content encryption key is then encrypted itself using the algorithm specified by EncryptionAlgorithm. The content encryption key is not directly exposed in the API as it is randomly generated.

After calling this method the compact serialized JWE string is written to the specified output location. For instance:

eyJhbGciOiJBMjU2R0NNS1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2IiwiaXYiOiJMa0tNeTZ5Qlpfbzh6QW92IiwidGFnIjoiSmpMTkRsV3l3bWt3V2pMa0NLU0xxQSJ9.wiwySYm6fXZre-3IdT1tb_02KMQDrMICwUawVf7Gjhc.k84s7ne8J41QnA5BQ31k_A.kjIveRjjNYV4x92CVE9Agw.uAygkyeO2KWeFQIy9JLU0A

The component is agnostic of the payload that is encrypted. Any value may be encrypted. KeyId may be set to include an identifier to help the receiving party identify the key or certificate used to encrypt the data. The following properties are applicable when calling this method:

Input and Output Properties

The component 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:

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

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

Notes for AES Algorithms (A128KW, A192KW, A256KW, A128GCMKW, A192GCMKW, A256GCMKW)

When EncryptionAlgorithm is set to a AES algorithm Key must be set to a key of appropriate length for the algorithm. For instance a 256 bit key would be used for A256KW.

The example below uses the EzRand component to generate a key, but the key may be created using any method. The key must be known by both parties in order for encryption and decryption to take place.


//Generate a 256 bit (32 byte) key
Ezrand rand = new Ezrand();
rand.RandBytesLength = 32;
rand.GetNextBytes();
byte[] key = rand.RandBytesB;

//Encrypt the payload using A256KW
Jwe jwe = new Jwe();
jwe.KeyB = key;
jwe.InputMessage = "test data";
jwe.EncryptionAlgorithm = JweEncryptionAlgorithms.eaA256KW;
jwe.Encrypt();

string encryptedData = jwe.OutputMessage;

To use an existing AES key provide the bytes to the Key property. For instance:


byte[] key = new byte[] { 164, 60, 194, 0, 161, 189, 41, 38, 130, 89, 141, 164, 45, 170, 159, 209, 69, 137, 243, 216, 191, 131, 47, 250, 32, 107, 231, 117, 37, 158, 225, 234 };

//Encrypt the payload using A256KW
Jwe jwe = new Jwe();
jwe.KeyB = key;
jwe.InputMessage = "test data";
jwe.EncryptionAlgorithm = JweEncryptionAlgorithms.eaA256KW;
jwe.Encrypt();

string encryptedData = jwe.OutputMessage;

Notes for RSA Algorithms (RSA1_5, RSA-OEAP, RSA-OAEP-256)

The RSA based algorithms use asymmetric encryption. Encrypting is done with a public key and decryption is done with a private key. The public certificate should be in PEM (base64) format. For instance:


Jwe jwe = new Jwe();
jwe.Certificate = new Certificate("..\\recipient.cer");
jwe.InputMessage = "test data";
jwe.EncryptionAlgorithm = JweEncryptionAlgorithms.eaRSA_OAEP;
jwe.Encrypt();

string encryptedData = jwe.OutputMessage;

Notes for ECDH Algorithms (ECDH-ES, ECDH-ES+A128KW, ECDH-ES+A192KW, ECDH-ES+A256KW)

ECDH algorithms require a valid ECC public key to encrypt the message. If the key was originally created with the ECC component the PEM encoded PublicKey may be used directly with the Certificate property. An example PEM encoded public certificate created by the ECC component:

-----BEGIN PUBLIC KEY-----
MIIBMjCB7AYHKoZIzj0CATCB4AIBATAsBgcqhkjOPQEBAiEA/////wAAAAEAAAAAAAAAAAAA
AAD///////////////8wRAQg/////wAAAAEAAAAAAAAAAAAAAAD///////////////wEIFrG
NdiqOpPns+u9VXaYhrxlHQawzFOw9jvOPD4n0mBLBEEEaxfR8uEsQkf4vOblY6RA8ncDfYEt
6zOg9KE5RdiYwpZP40Li/hp/m47n60p8D54WK84zV2sxXs7LtkBoN79R9QIhAP////8AAAAA
//////////+85vqtpxeehPO5ysL8YyVRAgEBA0EEIC5rbLp11Mnz6cBXLLriaDIov3rm8RAY
x/OR0bOKiff0cQy+sLVaxjseqFk/+Xvl4ORSv5Z6HdHv5GyEpA0UoA==
-----END PUBLIC KEY-----


Jwe jwe = new Jwe();
jwe.Certificate = new Certificate(CertStoreTypes.cstPublicKeyFile, pubKeyFile, "", "*");
jwe.InputMessage = "test data";
jwe.EncryptionAlgorithm = JweEncryptionAlgorithms.eaECDH_ES_A256KW;
jwe.Encrypt();

string encryptedData = jwe.OutputMessage;

To use an ECC public key created by other means the ECC component may be used to import the key parameters. Populate the Rx and Ry properties of the ECC component first to obtain the PEM formatted public key. For instance:


byte[] x_bytes = new byte[] { 171, 170, 196, 151, 94, 196, 231, 12, 128, 232, 17, 61, 45, 105, 41, 209, 192, 187, 112, 242, 110, 178, 95, 240, 36, 55, 83, 171, 190, 176, 78, 13 };
byte[] y_bytes = new byte[] { 197, 75, 134, 245, 245, 28, 199, 9, 7, 117, 1, 54, 49, 178, 135, 252, 62, 89, 35, 180, 117, 80, 231, 23, 110, 250, 28, 124, 219, 253, 224, 156 };

Ecc ecc = new Ecc();
ecc.Key.RxB = x_bytes;
ecc.Key.RyB = y_bytes;

string pubKey = ecc.Key.PublicKey;

Jwe jwe = new Jwe();
jwe.Certificate = new Certificate(CertStoreTypes.cstPublicKeyFile, pubKey, "", "*");
jwe.InputMessage = "test data";
jwe.EncryptionAlgorithm = JweEncryptionAlgorithms.eaECDH_ES_A256KW;
jwe.Encrypt();

string encryptedData = jwe.OutputMessage;

Notes for PBES Algorithms (PBES2-HS256+A128KW, PBES2-HS384+A192KW, PBES2-HS512+A256KW

PBES algorithms derive a content encryption key from the KeyPassword property. Set KeyPassword to a shared secret.


Jwe jwe = new Jwe();
jwe.KeyPassword = "secret";
jwe.InputMessage = "test data";
jwe.EncryptionAlgorithm = JweEncryptionAlgorithms.eaPBES2_HS512_A256KW;
jwe.Encrypt();

string encryptedData = jwe.OutputMessage;

Notes for Direct Shared Keys

When EncryptionAlgorithm is set to Direct the Key property must be set to a valid symmetric key that will be used directly by the ContentEncryptionAlgorithm. In this case a content encryption key is not generated randomly, the Key is used instead. The length of the specified Key must be valid for the selected ContentEncryptionAlgorithm. For instance:


//Generate a 256 bit (32 byte) key
Ezrand rand = new Ezrand();
rand.RandBytesLength = 32;
rand.GetNextBytes();

byte[] key = rand.RandBytesB;

Jwe jwe = new Jwe();
jwe.EncryptionAlgorithm = JweEncryptionAlgorithms.eaDir;
jwe.ContentEncryptionAlgorithm = JweContentEncryptionAlgorithms.ceaA256GCM;
jwe.KeyB = key;
jwe.InputMessage = "test data";
jwe.Encrypt();

string encryptedData = jwe.OutputMessage;

Decrypting

The Decrypt method may be used to decrypt a received JWE message. Before calling the Decrypt method set InputMessage or InputFile to a valid compact serialized JWE string. For instance:

eyJhbGciOiJBMjU2R0NNS1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2IiwiaXYiOiJMa0tNeTZ5Qlpfbzh6QW92IiwidGFnIjoiSmpMTkRsV3l3bWt3V2pMa0NLU0xxQSJ9.wiwySYm6fXZre-3IdT1tb_02KMQDrMICwUawVf7Gjhc.k84s7ne8J41QnA5BQ31k_A.kjIveRjjNYV4x92CVE9Agw.uAygkyeO2KWeFQIy9JLU0A

The type and format of the private key depends on the algorithm used to encrypt the data. The following table summarizes the relationship:

AlgorithmPrivate Key Location
AESKey
RSA and ECDHCertificate
PBESKeyPassword

If the correct Key or Certificate is not known ahead of time the KeyId parameter of the RecipientInfo event may be used to identify the correct key.

If this method returns without error decryption was successful. If decryption fails then this method throws an exception. After calling this method the payload will be present in the OutputMessage or file specified by OutputFile and the HeaderParams property will contain the headers. Headers of the parsed message are also available through the HeaderParam event.

The following properties are applicable when calling this method:

Input and Output Properties

The component 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:

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

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

Notes for AES Algorithms (A128KW, A192KW, A256KW, A128GCMKW, A192GCMKW, A256GCMKW)

To decrypt messages that use AES encryption Key must be set to a key of appropriate length for the algorithm. For instance a 256 bit key would be used for A256KW.

The key must be known by both parties in order for encryption and decryption to take place.


byte[] key = new byte[] { 164, 60, 194, 0, 161, 189, 41, 38, 130, 89, 141, 164, 45, 170, 159, 209, 69, 137, 243, 216, 191, 131, 47, 250, 32, 107, 231, 117, 37, 158, 225, 234 };

Jwe jwe = new Jwe();
jwe.KeyB = key;
jwe.InputMessage = encryptedData;
jwe.Decrypt();

string decryptedData = jwe.OutputMessage;

Notes for RSA Algorithms (RSA1_5, RSA-OEAP, RSA-OAEP-256)

The RSA based algorithms use asymmetric encryption. Encrypting is done with a public key and decryption is done with a private key. The certificate with private key must be specified. For instance:


Jwe jwe = new Jwe();
jwe.Certificate = new Certificate(CertStoreTypes.cstPFXFile, "..\\jwt.pfx", "password", "*");
jwe.InputMessage = encryptedData;
jwe.Decrypt();

string decryptedData = jwe.OutputMessage;

Notes for ECDH Algorithms (ECDH-ES, ECDH-ES+A128KW, ECDH-ES+A192KW, ECDH-ES+A256KW)

ECDH algorithms require a valid ECC private key to decrypt the message. If the key was originally created with the ECC component the PEM encoded PrivateKey may be used directly with the Certificate property.


Jwe jwe = new Jwe();
jwe.Certificate = new Certificate(CertStoreTypes.cstPEMKeyFile, privKeyFile, "", "*");
jwe.InputMessage = encryptedData;
jwe.Decrypt();

string decryptedData = jwe.OutputMessage;

To use an ECC private key created by other means the ECC component may be used to import the key parameters. Populate the Rx, Ry, and KB properties of the ECC component first to obtain the PEM formatted public key. For instance:


Ecc ecc = new Ecc();

byte[] x_bytes = new byte[] { 171, 170, 196, 151, 94, 196, 231, 12, 128, 232, 17, 61, 45, 105, 41, 209, 192, 187, 112, 242, 110, 178, 95, 240, 36, 55, 83, 171, 190, 176, 78, 13 };
byte[] y_bytes = new byte[] { 197, 75, 134, 245, 245, 28, 199, 9, 7, 117, 1, 54, 49, 178, 135, 252, 62, 89, 35, 180, 117, 80, 231, 23, 110, 250, 28, 124, 219, 253, 224, 156 };
byte[] k_bytes = new byte[] { 81, 65, 201, 24, 235, 249, 162, 148, 169, 150, 109, 181, 61, 238, 145, 122, 31, 30, 151, 94, 239, 90, 222, 217, 63, 103, 54, 2, 176, 232, 248, 168 };

ecc.Key.RxB = x_bytes;
ecc.Key.RyB = y_bytes;
ecc.Key.KB = k_bytes;

string privKey = ecc.Key.PrivateKey;

Jwe jwe = new Jwe();
jwe.Certificate = new Certificate(CertStoreTypes.cstPEMKeyBlob, privKey, "", "*");
jwe.InputMessage = encryptedData;
jwe.Decrypt();

string decryptedData = jwe.OutputMessage;

Notes for PBES Algorithms (PBES2-HS256+A128KW, PBES2-HS384+A192KW, PBES2-HS512+A256KW

PBES algorithms derive a content encryption key from the KeyPassword property. Set KeyPassword to the shared secret.


Jwe jwe = new Jwe();
jwe.KeyPassword = "secret";
jwe.InputMessage = encryptedData;
jwe.Decrypt();

string decryptedData = jwe.OutputMessage;

Notes for Direct Shared Keys

When Direct encryption is used the Key property must be set to a valid symmetric key that will be used directly by the ContentEncryptionAlgorithm. For instance:


byte[] key = new byte[] { 164, 60, 194, 0, 161, 189, 41, 38, 130, 89, 141, 164, 45, 170, 159, 209, 69, 137, 243, 216, 191, 131, 47, 250, 32, 107, 231, 117, 37, 158, 225, 234 };

Jwe jwe = new Jwe();
jwe.KeyB = key;
jwe.InputMessage = encryptedData;
jwe.Decrypt();

string decryptedData = jwe.OutputMessage;

Other Functionality

In addition to standard encrypting and decrypting the component also supports a variety of other features including:

  • Adding custom header parameters with AddHeaderParam
  • Enforcing algorithm restrictions when decrypting by setting StrictValidation
  • Inspect the JWE headers without decrypting by calling Parse

Property List


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

CertificateThe certificate used for encryption or decryption.
ContentEncryptionAlgorithmThe algorithm used to encrypt the content.
EncryptionAlgorithmThe key encryption algorithm.
HeaderParamsThe JOSE header parameters.
InputFileThe file to process.
InputMessageThe message to process.
KeyThe secret key for the AES algorithm.
KeyIdThe Id of the key used to encrypt the message.
KeyPasswordThe key password used in the PBES algorithm.
OutputFileThe output file when encrypting or decrypting.
OutputMessageThe output message after processing.
OverwriteIndicates whether or not the component should overwrite files.

Method List


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

addHeaderParamAdds additional header parameters.
configSets or retrieves a configuration setting.
decryptDecrypts the payload.
encryptEncrypts the payload with the specified algorithms.
parseParses the compact serialized JWE string.
resetResets the component.
setInputStreamSets the stream from which the component will read data.
setOutputStreamSets the stream to which the component will write data.

Event List


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

ErrorInformation about errors during data delivery.
HeaderParamFires once for each JOSE header parameter.
RecipientInfoFired with information about the recipient key of the encrypted message.

Configuration Settings


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

CloseInputStreamAfterProcessWhether to close the input stream after processing.
CloseOutputStreamAfterProcessWhether to close the output stream after processing.
CompressionAlgorithmThe compression algorithm to use.
PartyUInfoInformation about the producer of the message.
PartyVInfoInformation about the recipient of the message.
PBES2CountThe PBKDF2 iteration count.
PBES2SaltLengthThe salt input value length.
RawHeaderHolds the raw JOSE header.
StrictValidationRequires specific algorithm when decrypting.
BuildInfoInformation about the product's build.
GUIAvailableTells the component whether or not a message loop is available for processing events.
LicenseInfoInformation about the current license.
UseDaemonThreadsWhether threads created by the component are daemon threads.
UseInternalSecurityAPITells the component whether or not to use the system security libraries or an internal implementation.

Copyright (c) 2022 /n software inc. - All rights reserved.
IPWorks Encrypt 2020 Android Edition - Version 20.0 [Build 8161]