Kong JWT Signer | Kong Docs

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Looking for the plugin's configuration parameters? You can find them in the Kong JWT Signer configuration reference doc.

The Kong JWT Signer plugin makes it possible to verify, sign, or re-sign one or two tokens in a request. With a two-token request, one token is allocated to an end user and the other token to the client application, for example.

The plugin refers to tokens as an access token and channel token. Tokens can be any valid verifiable tokens. The plugin supports both opaque tokens through introspection, and signed JWT tokens through signature verification. There are many configuration parameters available to accommodate your requirements.

Configuration notes

Most of the plugin’s configuration parameters are optional, but you need to specify some options to actually make the plugin work:

For example, signature verification cannot be done without the plugin knowing about config.access_token_jwks_uri and/or config.channel_token_jwks_uri.
Also for introspection to work, you need to specify introspection endpoints config.access_token_introspection_endpoint and/or config.channel_token_introspection_endpoint.

Manage key signing

If you specify config.access_token_keyset or config.channel_token_keyset with either an http:// or https:// prefix, it means that token signing keys are externally managed by you. In that case, the plugin loads the keys just like it does for config.access_token_jwks_uri and config.channel_token_jwks_uri. If the prefix is not http:// or https:// (such as "my-company" or "kong"), Kong autogenerates JWKS for supported algorithms.

External JWKS specified with config.access_token_keyset or config.channel_token_keyset should also contain private keys with supported alg, either "RS256" or "RS512" for now. External URLs that contain private keys should be protected so that only Kong can access them. Currently, Kong doesn’t add any authentication headers when it loads the keys from an external endpoint, so you have to do it with network level restrictions. If it is a common need to manage private keys externally instead of allowing Kong to autogenerate them, we can add another parameter for adding an authentication header (possibly similar to config.channel_token_introspection_authorization).

The key size (the modulo) for RSA keys is currently hard-coded to 2048 bits.

Consumer mapping

The following parameters let you provide consumer mapping:

config.access_token_consumer_claim
config.access_token_introspection_consumer_claim
config.channel_token_consumer_claim
config.channel_token_introspection_consumer_claim

You can map only once. The plugin applies mappings in the following order:

access token introspection results
access token jwt payload
access token introspection results
access token jwt payload

The mapping order depends on input (opaque or JWT).

When mapping is done, no other mappings are used. If access token already maps to a Kong consumer, the plugin does not try to map a channel token to a consumer anymore and does not even error in that case.

A general rule is to map either the access token or the channel token.

Kong Admin API Endpoints

This plugin also provides a few Admin API endpoints, and some actions upon them.

Cached JWKS Admin API Endpoint

The plugin caches JWKS specified with config.access_token_jwks_uri and config.channel_token_jwks_uri to Kong database for quicker access to them. The plugin further caches JWKS in Kong node’s shared memory, and on process a level memory for even quicker access. When the plugin is responsible for signing the tokens, it also stores its own keys in the database.

Admin API endpoints never reveal private keys but do reveal public keys. Private keys that the plugin autogenerates can only be accessed from database directly (at least for now). Private parts in JWKS include properties such as d, p, q, dp, dq, qi, and oth. For public keys that are using a symmetric algorithm (such as HS256) and include k parameter, that is not hidden from Admin API as that is practically used both to verify and to sign. This makes it a bit problematic to use, and we strongly suggest using asymmetric (or public key) algorithms. Doing so also makes rotating the keys easier because the public keys can be shared between parties and published without revealing their secrets.

View all of the public keys that Kong has loaded or generated:

GET kong:8001/jwt-signer/jwks

Example:

curl -X GET http://<kong>:8001/jwt-signer/jwks

{
    "data": [
        {
            "created_at": 1535560520731,
            "id": "c1d2d9b7-ac3a-4ca4-b595-453acd78925e",
            "keys": [
                {
                    "alg": "RS256",
                    "e": "AQAB",
                    "kid": "aXKFjIY80eM_H4rqhT6iaOfdL5iDHDHjag2BWLaxeJA",
                    "kty": "RSA",
                    "n": "qDjxLGSa4jI14ctmvjMDQzZDfZJcXS6G6-wcVxLsQgrIWc_JnZ44b1ApAokFwaZsig4oNFLQYAMdapZSORI2jNlZ9lsJ-b3VZUz0gB5jGaFAyx7G1Uh46w_-2JZKI4wW8KinJ8VZayobSYS3eg6p3f34t2mDv36Uwa4B8DZKo8cE0JE8T2ne2lyS18W9bJkpfIoctcDjzsvFTg4NbEF3Y61q5v_6icxyJkB9JtS2JE1RjJxmBDOb_ETCLyIiN0Wlb9OdLX_HSdY3DRfnYNl3XAaPdqr8QifqidfdWI4YnJiJ3mYAgI-E37waZ0-1-Ykt-mpvUX1l_UvAdxqetGuC5Q",
                    "use": "sig"
                },
                {
                    "alg": "RS512",
                    "e": "AQAB",
                    "kid": "xb_lFJbpaVuo7cWO7XADl0PsL4G97VFpFg3hIgRiJHQ",
                    "kty": "RSA",
                    "n": "vLY2u2q1gmzysPCbjq7mSDwh2oeRLZ3A047gn0-JsNWF2BZrgMUlB5cnKHOUPAD2ugHjUAOVMy_1d6FO2VBxV6i66KgWM_CMu0sqpmM-n7iUq8TCbpOX5mWczt3GutXPw960--LGyFTuuy2xi1wVYW1WbDIvb4oLo9b0G1eJIjvtSjmQ8tiBkiIxnRGKKxeZl0oTX99v6Z9X1aXoQ11y46l4_IGsN1b8ZWfBJ7Glyi80trWIs6z-EmZED6gdRushRT98GHofqTPRaaOnOJ1itHECj6U82ec6UU-IBtryGqUn_PQ9fUpI1Ru-0jGEcMY3aBZdZ4Uy_189ELK4jqn28w",
                    "use": "sig"
                }
            ],
            "name": "kong",
            "previous": [],
            "updated_at": 1535560520731
        },
        {
            "created_at": 1535560520379,
            "id": "d9d5b731-55fe-4cad-829f-6aba4b2d8823",
            "keys": [
                {
                    "alg": "RS256",
                    "e": "AQAB",
                    "kid": "b863b534069bfc0207197bcf831320d1cdc2cee2",
                    "kty": "RSA",
                    "n": "8h6tCwOYDPtzyFivNaIguQVc_yBO5eOA2kUu_MAN8s4VWn8tIfCbVvcAz3yNwQuGpkdNg8gTk9QmReXl4SE8m7aCa0iRcBBWLyPUt6TM1RkYE51rOGYhjWxo9V8ogMXSBclE6x0t8qFY00l5O34gjYzXtyvyBX7Sw5mGuNLVAzq2nsCTnIsHrIaBy70IKU3FLsJ_PRYyViXP1nfo9872q3mtn7bJ7_hqss0vDgUiNAqPztVIsrZinFbaTgXjLhBlUjFWgJx_g4p76CJkjQ3-puZRU5A0D04KvqQ_0AWcN1Q8pvwQ9V4uGHm6Bop9nUhIcZJYjjlTM9Pkx_JnVOfekw",
                    "use": "sig"
                },
                {
                    "alg": "RS256",
                    "e": "AQAB",
                    "kid": "55b854edf35f093b4708f72dec4f15149836e8ac",
                    "kty": "RSA",
                    "n": "xul55cFjIY7QFMhl79y_3MWK4rHDRqTu-C2VxaPqxbLUSW-LJp8hotDeIOdMEawi2WFNUUCrOpSl33CtX3oFeq7ytLS6y5aosoQMLlguGHnU7FBNvw9kNtR41ykvLphU5YGJVr_JVFAqJPcpB9cEo6f6Mo9i8_gfsXMhkyrm5eqXDFlgDfgfJ_oaMyfkBmhLO2sjgdLguy_x6jg1Ys3WK2DfsI0q7X_esbEStEiV9M9lHOYsmdikKO-CPK6_c5zzJgiIjoND47WEtWuuOp_izV6BeojK9JFPHxcOnX71__sTWYl2iv7cZUNQQeH3Kub6gfpfVjCExy_5qKvtdMnzrw",
                    "use": "sig"
                },
                {
                    "alg": "RS256",
                    "e": "AQAB",
                    "kid": "ba4aeae8b208ad9ae12b6610865f63961287b6d6",
                    "kty": "RSA",
                    "n": "1f7xnpGKS5pq7l2nE0iLQ1SYX3MVeOxFDdqzTLOzU_JCNrl_w0a3f1Ry0nRPGMjONaBodUAKKgVbTKT3v88Y8-8l4BAk7lnw0fjw404MfDCt2lHaLVY_WjCHfltsUbCklta_eSN92bYQX81wmlGhwWW5kAyagTkpsPGb04zZLWTPR5fYffdYfRY1r65VmzrZaniEq4HQUr49swKmH5yyqF_HrtkpXXAcqmPlsoh1rwm1G1fsDTiNgwhJD54oZ1z5h-_8S4a0XV5cfrAQw6zzRw2Yfe6_FSXVJdJjZ_qZmY_Eqay3Wv-FDr0mZGZg6RmTtDt5208lwUcB4j49kczUhw",
                    "use": "sig"
                }
            ],
            "name": "https://www.googleapis.com/oauth2/v3/certs",
            "previous": [],
            "updated_at": 1535560520379
        }
    ],
    "total": 2
}

Cached JWKS Admin API Endpoint for a Key Set

A particular key set can be accessed in another endpoint:

GET kong:8001/jwt-signer/jwks/<name-or-id>

Example:

curl -X GET http://<kong>:8001/jwt-signer/jwks/kong

{
    "keys": [
        {
            "alg": "RS256",
            "e": "AQAB",
            "kid": "v6el8V8dbrKY5w2PInkM468aSuODrKcfbt-44xdDIjk",
            "kty": "RSA",
            "n": "uJzCU_TangWMFk25_JggtkVNjtFfaaz3jERYEYrsb92KFK4FpjfenYYeo8XCGLphn-NcYJroHy3aVznTvU3O8B-5z27uFgXUzk_m-fJ5C4cyqBaJS_myuMOnx0SBl-V6rIGmbdAd0rxsR9SK4JXaZ7xPnQKl8Z6N_Be2iWzf8RUzgM51x7RLQWr55DXBz5IS0O3uYi0z2_xaTyhvZ01aGMGO8Jom1QZkSf2SBGVvQiff464wB_R9Uw8bnbDw6SI0A7JbvSTj80dsoB5YJaR6OZ7XzJX53J1-efiEPc-JTXnqsN1xd-7DbrwpGSui7cGU79H7rG2o-DdVtz649JVXHw",
            "use": "sig"
        },
        {
            "alg": "RS512",
            "e": "AQAB",
            "kid": "SBFmMBtMQzjQEYPDQ_7H5emJzfjX4-FBVE22_SRy5oU",
            "kty": "RSA",
            "n": "rPcrSYQKnJNfMd0AF2t8JGSRdSSOeEPwSpPNyq6T13NXWLBDzzmZC8gNURFrsB8hkeY_KUNe3rVZz__6Vp7_h5PxWXKIUFJT18Gl8mSJ_4ohWUFziWdLV1rliZ671Uo5My2_McgRFI2DfHCWCe5XL5ApKPv9YFT684_FfKpnvTIn7_rVoyQYp3g9Ud_7X5hJGEuBa3HKSGPhn-zh1A0kxnLwNrLms4t3bQZMamuR0R3XYXr76OwU0xQMsqy3_DwV1DJ0z9o0gFV8GSkYWYllVNwfGPXiTSUvTKWIARGV60jUaoYB1sG5yXyhgBcWn-XX5wcOG--aGfdWwlnYF7p_ow",
            "use": "sig"
        }
    ],
    "previous": []
}

The http://<kong>:8001/jwt-signer/jwks/kong is the URL that you can give to your upstream services for them to verify Kong-issued tokens. The response is a standard JWKS endpoint response. The kong suffix in the URI is the one that you can specify with config.access_token_issuer or config.channel_token_issuer.

You can also make a loopback to this endpoint by routing Kong proxy to this URL. Then you can use an authentication plugin to protect access to this endpoint, if that is needed.

You can also DELETE a key set by issuing following:

DELETE kong:8001/jwt-signer/jwks/<name-or-id>

Example:

curl -X DELETE http://<kong>:8001/jwt-signer/jwks/kong

The plugin automatically reloads or regenerates missing JWKS if it cannot find cached ones. The plugin also tries to reload JWKS if it cannot verify the signature of original access token or channel token, such as when the original issuer has rotated its keys and signed with the new one that is not found in Kong cache.

Cached JWKS Admin API Endpoint for a Key Set Rotation

Sometime you might want to rotate the keys Kong uses for signing tokens specified with config.access_token_keyset and config.channel_token_keyset, or perhaps reload tokens specified with config.access_token_jwks_uri and config.channel_token_jwks_uri. Kong stores and uses at most two set of keys: current and previous. If you want Kong to forget the previous keys, you need to rotate keys twice, as it effectively replaces both current and previous key sets with newly generated tokens or reloaded tokens if the keys were loaded from an external URI.

To rotate keys, send a POST request:

POST kong:8001/jwt-signer/jwks/<name-or-id>/rotate

Example:

curl -X POST http://<kong>:8001/jwt-signer/jwks/kong/rotate

Response:

{
    "keys": [
        {
            "alg": "RS256",
            "e": "AQAB",
            "kid": "WL-MciVclsUiIOo1IFBozrFmCIGHcYieGGny3RiENbU",
            "kty": "RSA",
            "n": "sOIf20LLUMcwaScetGnnljjkla_uZ1xQbWOy5cUjiDqku1MqiRgSvI9lM0A6USa4xtqGEnAhE-wZG7fqdWIUPgm3gZxmB6JjIV3E32PjWUtiVAiJUId3dMaGn4FSzU-TTKFAIB-xfO_0qoccaGfjsh2E5qeBGK1IBznnaw3ShnqdB53kJkSS0xgZ3NyCwh4zfTb0XeJq0l8U9xS3IdaVMj5EBOFvo-DBMneyICgLQaLIEB2KQ64aN2al4sLhKCL_Ui02s1F0igLdUr0nyhe7iFK6YIyhERMviDmv_HW7CfFcNVvB-dbpIfW0Z9SX4CtkpaAHdY4HPZFneJ4VtqYQLQ",
            "use": "sig"
        },
        {
            "alg": "RS512",
            "e": "AQAB",
            "kid": "6EIBzS288AfTm1atFHICYZ4SvWY3X9jnZEYQT3uKfXw",
            "kty": "RSA",
            "n": "zpxT7SlEmnWxquVwELysCCmrAkAvJb8eYHk3DLKEvjDDUVjA8u6KFoCBL6ySRg59kZESZ_30A0Oi1wWO85kUySlL_rtn-1PYPCUX_Yhsdoq0dYmD388l5VxRDdwVQh6c4VnbTZbJGk7RDm-dBe2xNwdfNs_C5f4pf-nGMyk1kqfgVRoYkrXuMAwd4xbeb-gh7ZdBNQO-LkMlLVGKbFe5bsnvG2ht202qx_VdHjN-spxbRUANCDRpPTAM1uEdB15EijZDLnwXZCywUsb0WIKA0bxxEJtH6tO7g8EujYqZB3Z-TaCq-dtq8lKT2FoRNx6-Zc3zVsRHb5RWqV2pgrKWZQ",
            "use": "sig"
        }
    ],
    "previous": [
        {
            "alg": "RS256",
            "e": "AQAB",
            "kid": "v6el8V8dbrKY5w2PInkM468aSuODrKcfbt-44xdDIjk",
            "kty": "RSA",
            "n": "uJzCU_TangWMFk25_JggtkVNjtFfaaz3jERYEYrsb92KFK4FpjfenYYeo8XCGLphn-NcYJroHy3aVznTvU3O8B-5z27uFgXUzk_m-fJ5C4cyqBaJS_myuMOnx0SBl-V6rIGmbdAd0rxsR9SK4JXaZ7xPnQKl8Z6N_Be2iWzf8RUzgM51x7RLQWr55DXBz5IS0O3uYi0z2_xaTyhvZ01aGMGO8Jom1QZkSf2SBGVvQiff464wB_R9Uw8bnbDw6SI0A7JbvSTj80dsoB5YJaR6OZ7XzJX53J1-efiEPc-JTXnqsN1xd-7DbrwpGSui7cGU79H7rG2o-DdVtz649JVXHw",
            "use": "sig"
        },
        {
            "alg": "RS512",
            "e": "AQAB",
            "kid": "SBFmMBtMQzjQEYPDQ_7H5emJzfjX4-FBVE22_SRy5oU",
            "kty": "RSA",
            "n": "rPcrSYQKnJNfMd0AF2t8JGSRdSSOeEPwSpPNyq6T13NXWLBDzzmZC8gNURFrsB8hkeY_KUNe3rVZz__6Vp7_h5PxWXKIUFJT18Gl8mSJ_4ohWUFziWdLV1rliZ671Uo5My2_McgRFI2DfHCWCe5XL5ApKPv9YFT684_FfKpnvTIn7_rVoyQYp3g9Ud_7X5hJGEuBa3HKSGPhn-zh1A0kxnLwNrLms4t3bQZMamuR0R3XYXr76OwU0xQMsqy3_DwV1DJ0z9o0gFV8GSkYWYllVNwfGPXiTSUvTKWIARGV60jUaoYB1sG5yXyhgBcWn-XX5wcOG--aGfdWwlnYF7p_ow",
            "use": "sig"
        }
    ]
}

Next Kong JWT Signer Configuration