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ID token encryption reference

This reference explains the format of encrypted ID tokens in detail and the algorithms and methods used for encryption.

ID token formats

An unencrypted ID token consists of two base64-encoded parts separated by a period (.). It takes the following format:

<header>.<body>

eyJhbGciOiJSUzI1NiJ9.eyJzdWIiOiJhbGljZSIsImlzcyI6Imh0dHBzOlwvXC9jMmlkLmNvbSIsImlhdCI6MTQxNjE1ODU0MX0
  • <header> : Contains metadata about the token, such as the signing algorithm used.
  • <body> : Contains the actual claims about the user, such as the user's identifier, issuer, and audience.

An encrypted ID token consists of five base64-encoded parts separated by a period (.). It takes the following format:

<header>.<Encrypted_Key>.<Initialization_Vector>.<Ciphertext>.<Authentication_Tag> 

eyJ4NXQiOiJOVEF4Wm1NeE5ETXlaRGczTVRVMVpHTTBNekV6T0RKaFpXSTRORE5sWkRVMU9HRmtOakZpTVEiLCJraWQiOiJOVEF4Wm1NeE5ETXlaRGczTVRVMVpHTTBNekV6T0RKaFpXSTRORE5sWkRVMU9HRmtOakZpTVEiLCJlbmMiOiJBMjU2R0NNIiwiYWxnIjoiUlNBMV81In0.Zwp2xDvYER9lAo43QrYrcaKz-tPLFPYZb2s4RontDDVyvdo-seYl6II2C1Wb4cQhXdipcB_Qj093xvLrJyZXWxeavqYhryeuHi2jgcs59MfV1U9hMaKqqjVN1pcZYSrxDzn5leBF5bw7_YKaD_R6cFY8VtpVv5j_U8WohtyIjM7_n2CsZ55vY8MUHCAYxzXK9_s75e6Ug8L4MEqpgeoJGQzYCxFrBFgGyDMv1jadLwNl4Y3yLhv4RLtQMU5AM6nODI601UfYdrapObF3mpl_74H_YdRqT28LepGMtkEXbjeRgB-FiFGLvYlrK4wygczLBKrcviVyzyhrIrqz3TYV3g.Lf5lECzAdyAGgP8t.SHBUZoWkqwW_7u0GElrUqX1tewqRaUMWdGPHxpLRPmpVuc7FwQ27-kdsQ6O1_twhZ7uzjzZaEkatNhMxy9k10733-r4GT1lTGVqidKiBZq3mRQu7qJpcz7JWUroNFRLxhSoqpLpC8_tAhkohzG-mE42xdEh4tNDy3pBtAG0fe42WrLtWTuyg5lpmOYSppOc2Gb6LcDr4MmxFNPgoatF0edJSgO-CpFJQTcXn-22lU2g7o22x3RcBx9_KZH0At3g9y9uTuBncExOoBRK_ZweKOl0q76TaLiv5faXINW15xz9hILA.RGYIL7FaQqAIMPAiQdkOig
  • <header>: Contains metadata about the token, such as the encryption algorithm and method used.
  • <Encrypted_Key>: Contains the Content Encryption Key (CEK) encrypted with the recipient's public key.
  • <Initialization_Vector> : Random value used in the symmetric encryption process.
  • <Ciphertext>: The actual encrypted ID token payload.
  • The <Authentication_Tag>: Used for integrity checks.

Encryption algorithms and methods

WSO2 Identity Server uses the JSON Web Encryption (JWE) standards to encrypt ID tokens. The encryption process involves the following two processes:

  • Encrypt the payload - WSO2 Identity Server generates a random Content Encryption Key (CEK) and uses it to encrypt the ID token payload using the specified symmetric encryption algorithm, known as the encryption method. WSO2 Identity Server support the following encryption methods:

    • A128GCM
    • A192GCM
    • A256GCM
    • A128CBC-HS256

    • A128CBC+HS256

    • A192CBC-HS384

Note

From update level 135 onwards, the A192CBC-HS384 encryption method is supported.

  • Encrypt the Content Encryption Key (CEK) - WSO2 Identity Server uses the registered public key of the application to encrypt the CEK using the specified asymmetric encryption algorithm, known as the encryption algorithm. WSO2 Identity Server supports the following encryption algorithms:

    • RSA1_5

    • RSA-OAEP

    • RSA-OAEP-256

    • RSA-OAEP-384
    • RSA-OAEP-512

Note

From update level 135 onwards, RSA-OAEP-256, RSA-OAEP-384, and RSA-OAEP-512 encryption algorithms are supported.

You can configure the default values of the encryption methods and encryption algorithms by making changes to the <IS_HOME>/repository/conf/deployment.toml file.

[oauth.oidc.id_token]
supported_encryption_algorithms=["RSA1_5","RSA-OAEP"]
supported_encryption_methods=["A128GCM","A192GCM","A256GCM","A128CBC-HS256","A128CBC+HS256"]