jwe-decrypt

jwe-decrypt

Reads a JWE-encrypted token from a request header, decrypts it with a symmetric key, and forwards the decrypted plaintext into another request header before the request is proxied upstream. Place it early in the request pipeline, before the upstream node.

Configuration

Key	Type	Default	Description
header	string	Authorization	Header carrying the encrypted token; matched case-insensitively. An optional Bearer prefix is stripped.
forward_header	string	Authorization	Header the decrypted plaintext is written to before proxying.
strict	boolean	true	When true, a request with no token is rejected. When false, a request with no token passes through unchanged.
key	string	—	Inline symmetric key, base64-encoded, that must decode to exactly 32 bytes (AES-256). Used for every request.
use_consumers	boolean	false	Resolve the key per request from the gateway consumers: section. The token's kid (in its protected header) selects the consumer whose jwe-decrypt credential is {key: <kid>, secret: <32-byte key>, is_base64_encoded: <bool>}.
alg	string	dir	Key-management algorithm. Only dir is supported; any other value is a config error.
enc	string	A256GCM	Content-encryption algorithm. Only A256GCM is supported; any other value is a config error.

At least one of key / use_consumers must be provided.

- id: jwe
  type: jwe-decrypt
  config:
    header: Authorization
    forward_header: Authorization
    strict: true
    use_consumers: true

With a consumer store:

consumers:
  - name: alice
    credentials:
      jwe-decrypt:
        key: alice-kid          # matched against the token's `kid`
        secret: "0123456789abcdef0123456789abcdef"  # 32 bytes
        is_base64_encoded: false

Behavior

The token is read from header (stripping a Bearer prefix), parsed as a 5-part JWE compact serialization (protected.encrypted_key.iv.ciphertext.tag), and its protected header is checked for alg: dir / enc: A256GCM. The 32-byte AES key comes from the inline key or, with use_consumers, from the consumer selected by the token's kid. The ciphertext is decrypted with AES-256-GCM (the protected header being the AEAD additional-authenticated-data, per RFC 7516).

On success the decrypted plaintext replaces the value of forward_header and the request continues through the success port. On any failure the request is rejected and routed through the error port:

• context.response.status_code = 401
• Body: {"error": "unauthorized", "message": "<reason>"} with content-type: application/json
• Error code appended to context.errors: JWE_INVALID

Failure covers a missing token (when strict), a malformed compact serialization, an unsupported alg/enc in the token, an unknown or missing kid, and any failed AEAD authentication (tampered ciphertext, wrong key).

Limitations

The plugin implements the dir (direct) key-management algorithm with A256GCM content encryption, and nothing else:

• Only dir + A256GCM is supported. There is no RSA-OAEP, ECDH-ES, key-wrap, or alternative content cipher. A node whose config sets alg/enc to anything else fails at config load; a token that declares another algorithm is rejected at request time with JWE_INVALID.
• The encrypted_key segment of the compact serialization must be empty (as it always is for dir). A non-empty segment is rejected.
• The consumer secret must be a 32-byte AES-256 key — either 32 raw bytes (is_base64_encoded: false) or base64url that decodes to 32 bytes (is_base64_encoded: true).
• All rejections return 401. A single 401 with the JWE_INVALID code is used for every rejection path, consistent with featherbit's other auth plugins.