Google Git
Sign in
third-party-mirror/benmcollins/libjwt/6e5f475c8281aace1be3785fa625e331e510537f
commit
6e5f475c8281aace1be3785fa625e331e510537f
[log]
author
Ben Collins <bcollins@libjwt.io>
Mon Jun 15 16:18:14 2026 -0400
committer
Ben Collins <bcollins@libjwt.io>
Mon Jun 15 16:18:14 2026 -0400
tree
0f53f34b0e72575c00d8159d6106d92307f5ee8e
parent
5a705e69924ac97afb0c260462b969bd68ea1855 [diff]
gnutls: drop the RSA-OAEP (SHA-1) OpenSSL fallback; just fail

GnuTLS/nettle cannot perform RSA-OAEP with SHA-1. The GnuTLS backend used to
delegate that case to OpenSSL when it was compiled in; now it simply rejects
plain RSA-OAEP (RSA-OAEP-256 remains native). This makes the GnuTLS backend's
behavior independent of whether OpenSSL is also built.

- gnutls/jwe.c: RSA-OAEP (SHA-1) encrypt/decrypt return failure instead of
  calling openssl_*_cek_rsa_pem.
- Remove the now-dead openssl_encrypt_cek_rsa_pem / openssl_decrypt_cek_rsa_pem
  helpers (and their declarations); they existed solely for this fallback. The
  shared rsa_oaep_{encrypt,decrypt}_pkey helpers stay (used by the OpenSSL ops);
  their comments are updated.
- tests/jwe_rsa.c: the GnuTLS backend never supports plain RSA-OAEP now,
  regardless of OpenSSL.
- README and doxygen/mainpage.dox: mark RSA-OAEP (SHA-1) unsupported under
  GnuTLS, drop the now-unused "OpenSSL fallback" legend entry, and update the
  note.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Ben Collins <bcollins@libjwt.io>
7 files changed
tree: 0f53f34b0e72575c00d8159d6106d92307f5ee8e
  1. .github/
  2. cmake/
  3. doxygen/
  4. images/
  5. include/
  6. libjwt/
  7. tests/
  8. tools/
  9. .gitignore
  10. CLAUDE.md
  11. CMakeLists.txt
  12. codecov.yml
  13. LICENSE
  14. README.md
  15. SECURITY.md
README.md

LibJWT - The C JWT Library

codecov

maClara

:bulb: Supported Standards

StandardRFCDescription
JWS:page_facing_up: RFC-7515JSON Web Signature
JWE:page_facing_up: RFC-7516JSON Web Encryption
JWK:page_facing_up: RFC-7517JSON Web Keys and Sets
JWA:page_facing_up: RFC-7518JSON Web Algorithms
JWT:page_facing_up: RFC-7519JSON Web Token

[!NOTE] Throughout this documentation you will see links such as the ones above to RFC documents. These are relevant to that particular part of the library and are helpful to understand some of the specific standards that shaped the development of LibJWT.

:construction: Build Prerequisites

Required

  • A JSON library: either Jansson (>= 2.0, the default) or json-c (>= 0.16, selected with -DWITH_JSON_C=ON). The two are interchangeable.
  • CMake (>= 3.7)

Crypto support

  • OpenSSL (>= 3.0.0)
  • GnuTLS (>= 3.8.8)
  • MbedTLS (>= 3.6.0)

[!NOTE] At least one crypto backend is required, but any non-empty combination works. OpenSSL is enabled by default and can be disabled with -DWITH_OPENSSL=OFF. Each backend parses and converts JWK(S) natively.

Algorithm support matrix

JWS Algorithm algOpenSSLGnuTLSMbedTLS
HS256 HS384 HS512:white_check_mark::white_check_mark::white_check_mark:
ES256 ES384 ES512:white_check_mark::white_check_mark::white_check_mark:
RS256 RS384 RS512:white_check_mark::white_check_mark::white_check_mark:
EdDSA using ED25519:white_check_mark::white_check_mark::x:
EdDSA using ED448:white_check_mark::white_check_mark::x:
PS256 PS384 PS512:white_check_mark::white_check_mark::white_check_mark:
ES256K:white_check_mark::x::white_check_mark:

JWE

LibJWT supports JWE (RFC 7516) in both the Compact Serialization and the JSON Serialization (the Flattened form and the General form with one or more recipients). A JWE uses two algorithms: a key management algorithm (alg) and a content encryption algorithm (enc).

JWE serializationRecipientsSupported
Compact (RFC 7516 §7.1)one:white_check_mark:
JSON Flattened (RFC 7516 §7.2.2)one:white_check_mark:
JSON General (RFC 7516 §7.2.1)one or more:white_check_mark:

With the JSON serializations the plaintext is encrypted once with a single CEK; each recipient wraps that CEK independently, so any recipient's key can decrypt the token. They also carry an optional shared unprotected header, per-recipient headers, and an application AAD member.

Legend: :white_check_mark: native implementation  ·  :x: not supported

JWE key management algOpenSSLGnuTLSMbedTLS
dir (Direct Encryption):white_check_mark::white_check_mark::white_check_mark:
A128KW A192KW A256KW:white_check_mark::white_check_mark::white_check_mark:
RSA-OAEP (SHA-1):white_check_mark::x::white_check_mark:
RSA-OAEP-256:white_check_mark::white_check_mark::white_check_mark:
ECDH-ES (+ +A128KW/+A192KW/+A256KW):white_check_mark::white_check_mark::white_check_mark:
JWE content encryption encOpenSSLGnuTLSMbedTLS
A128GCM A192GCM A256GCM:white_check_mark::white_check_mark::white_check_mark:
A128CBC-HS256 A192CBC-HS384 A256CBC-HS512:white_check_mark::white_check_mark::white_check_mark:

[!NOTE] ECDH-ES supports both Direct Key Agreement and the +A*KW key wrapping modes, on the EC curves P-256/384/521 and the OKP curves X25519/X448, with optional apu/apv PartyInfo. RSA1_5 and zip (compression) are intentionally not supported. Each backend implements JWE natively. GnuTLS/Nettle cannot perform RSA-OAEP with SHA-1, so the GnuTLS backend does not support plain RSA-OAEP (RSA-OAEP-256 is native).

Optional

:books: Docs and Source

:link: Current Docs

:link: Legacy Docs v2.1.1

:link: GitHub Repo

:package: Pre-built Packages

LibJWT is available in most Linux distributions as well as through Homebrew for Linux, macOS, and Windows.

:hammer: Build Instructions

With CMake:

$ mkdir build
$ cd build
$ cmake ..
$ make