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Security considerations

This library handles sensitive cryptographic material during request and response processing. The following rules apply to implementation, tests, diagnostics, and operations.

Never log sensitive values​

Do not log:

  • plaintext request bodies,
  • plaintext response bodies,
  • compact JWE values,
  • CEKs,
  • private keys,
  • decrypted JWE-Response-Key values,
  • full JWK key material.

Review traces and test logs must use redacted placeholders:

<compact-jwe length=...>
<redacted 32 bytes>
<redacted>

Public JWKS only​

The JWKS endpoint must only publish public keys.

The client rejects invalid JWKS data, including keys with private parameters.

Supported algorithms​

Request body JWE and JWE-Response-Key use:

alg: RSA-OAEP-256
enc: A256GCM

Encrypted backend responses use:

alg: dir
enc: A256GCM

Unsupported algorithms are rejected.

Request-local response CEK​

The response CEK is generated per protected request.

It must not be:

  • reused across requests,
  • stored in local storage or session storage,
  • cached globally,
  • logged,
  • exposed to application code.

Transport content type​

Protected payloads use:

Content-Type: application/jose

Protected responses use:

Content-Type: application/jose

The original content type is carried in the JWE cty protected header.