lib: Add post-quantum cryptography support

This adds initial support for runtime-configurable encryption and
post-quantum Key Encapsulation Mechanisms (KEMs) and authentication
(ML-DSA).

Supported key exchange algorithms:

  ECDH: prime256v1, secp384r1, secp521r1, X25519, X448
  Finite Field DH: ffdhe2048, ffdhe3072, ffdhe4096
  ML-KEM (FIPS 203): ML-KEM-512, ML-KEM-768, ML-KEM-1024
  Hybrid KEMs: X25519MLKEM768, X448MLKEM1024

Supported ciphers:
  AEAD: aes-128-gcm, aes-192-gcm, aes-256-gcm, chacha20-poly1305
  CTR: aes-128-ctr, aes-192-ctr, aes-256-ctr

Supported HKDFs:
  sha256, sha384, sha512, sha3-256, sha3-384, sha3-512,
  blake2b512, blake2s256

Supported Digests for DSA:
  sha256, sha384, sha512, sha3-256, sha3-384, sha3-512,
  blake2b512, blake2s256

PQC support requires OpenSSL 3.4.0+ and is detected automatically via
CMake. A DISABLE_PQC option allows building without PQC even when
available.

KEMs differ from traditional DH in that they require asymmetric roles:
one party encapsulates to the other's public key. This creates a
coordination problem during simultaneous reconnection attempts. The
kem_mode configuration parameter resolves this by pre-assigning roles:

  kem_mode=server  # Server encapsulates (1-RTT, full forward secrecy)
  kem_mode=client  # Client encapsulates (0-RTT, cached server key)

The enc.conf file format supports:

  kex=<algorithm>      # Key exchange algorithm
  cipher=<algorithm>   # Symmetric cipher
  kdf=<KDF>            # Key derivation function
  digest=<digest>      # Digest for DSA
  kem_mode=<mode>      # Server (default) or client
  none                 # Disable encryption

The OAP protocol is extended to negotiate algorithms and exchange KEX
data. All KEX messages are signed using existing authentication
infrastructure for integrity and replay protection.

Tests are split into base and _pqc variants to handle conditional PQC
compilation (kex_test.c/kex_test_pqc.c, oap_test.c/oap_test_pqc.c).

Bumped minimum required OpenSSL version for encryption to 3.0
(required for HKDF API). 1.1.1 is long time EOL.

Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks>
Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>

1 files changed, 125 insertions, 0 deletions

diff --git a/include/test/certs.h b/include/test/certs.h
new file mode 100644
index 00000000..1b847406
--- /dev/null
+++ b/include/test/certs.h
@@ -0,0 +1,125 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2026
+ *
+ * Test certificates - ECDSA/P-256 signed certificates
+ *
+ *    Dimitri Staessens <dimitri@ouroboros.rocks>
+ *    Sander Vrijders   <sander@ouroboros.rocks>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * version 2.1 as published by the Free Software Foundation.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., http://www.fsf.org/about/contact/.
+ */
+
+#ifndef TEST_CERTS_H
+#define TEST_CERTS_H
+
+/*
+* Certificates created following the guide
+*   Building an openssl certificate authority
+* on
+*   https://community.f5.com/kb/technicalarticles/
+*/
+
+/* Root certificate for CA ca.unittest.o7s */
+static const char * root_ca_crt_ec = \
+"-----BEGIN CERTIFICATE-----\n"
+"MIICXTCCAgOgAwIBAgIURlENlCOy1OsA/AXFscPUQ2li8OYwCgYIKoZIzj0EAwIw\n"
+"fDELMAkGA1UEBhMCQkUxDDAKBgNVBAgMA09WTDEOMAwGA1UEBwwFR2hlbnQxDDAK\n"
+"BgNVBAoMA283czEVMBMGA1UECwwMdW5pdHRlc3QubzdzMRgwFgYDVQQDDA9jYS51\n"
+"bml0dGVzdC5vN3MxEDAOBgkqhkiG9w0BCQEWASAwHhcNMjUwODAzMTg1MzE1WhcN\n"
+"NDUwNzI5MTg1MzE1WjB8MQswCQYDVQQGEwJCRTEMMAoGA1UECAwDT1ZMMQ4wDAYD\n"
+"VQQHDAVHaGVudDEMMAoGA1UECgwDbzdzMRUwEwYDVQQLDAx1bml0dGVzdC5vN3Mx\n"
+"GDAWBgNVBAMMD2NhLnVuaXR0ZXN0Lm83czEQMA4GCSqGSIb3DQEJARYBIDBZMBMG\n"
+"ByqGSM49AgEGCCqGSM49AwEHA0IABEPMseCScbd/d5TlHmyYVszn/YGVeNdUCnFR\n"
+"naOr95WlTNo3MyKKBuoiEFwHhjPASgXr/VDVjJLSyM3JUPebAcGjYzBhMB0GA1Ud\n"
+"DgQWBBQkxjMILHH6lZ+rnCMnD/63GO3y1zAfBgNVHSMEGDAWgBQkxjMILHH6lZ+r\n"
+"nCMnD/63GO3y1zAPBgNVHRMBAf8EBTADAQH/MA4GA1UdDwEB/wQEAwIBhjAKBggq\n"
+"hkjOPQQDAgNIADBFAiEA1jVJWW4idkCgAYv0m2LT9C33Dq42aLyRkJ+9YdzDqLwC\n"
+"IHT6MS4I0k52YP/hxoqWVBbpOW79PKYMRLyXTk1r7+Fa\n"
+"-----END CERTIFICATE-----\n";
+
+/* Certificate for intermediary im.unittest.o7s used for signing */
+static const char * im_ca_crt_ec = \
+"-----BEGIN CERTIFICATE-----\n"
+"MIICbTCCAhOgAwIBAgICEAMwCgYIKoZIzj0EAwIwfDELMAkGA1UEBhMCQkUxDDAK\n"
+"BgNVBAgMA09WTDEOMAwGA1UEBwwFR2hlbnQxDDAKBgNVBAoMA283czEVMBMGA1UE\n"
+"CwwMdW5pdHRlc3QubzdzMRgwFgYDVQQDDA9jYS51bml0dGVzdC5vN3MxEDAOBgkq\n"
+"hkiG9w0BCQEWASAwHhcNMjUwODAzMTkwMjU3WhcNNDUwNzI5MTkwMjU3WjBaMQsw\n"
+"CQYDVQQGEwJCRTEMMAoGA1UECAwDT1ZMMQwwCgYDVQQKDANvN3MxFTATBgNVBAsM\n"
+"DHVuaXR0ZXN0Lm83czEYMBYGA1UEAwwPaW0udW5pdHRlc3QubzdzMFkwEwYHKoZI\n"
+"zj0CAQYIKoZIzj0DAQcDQgAEdlra08XItIPtVl5veaq4UF6LIcBXj2mZFqKNEXFh\n"
+"l9uAz6UAbIc+FUPNfom6dwKbg/AjQ82a100eh6K/jCY7eKOBpjCBozAdBgNVHQ4E\n"
+"FgQUy8Go8BIO6i0lJ+mgBr9lvh2L0eswHwYDVR0jBBgwFoAUJMYzCCxx+pWfq5wj\n"
+"Jw/+txjt8tcwEgYDVR0TAQH/BAgwBgEB/wIBADAOBgNVHQ8BAf8EBAMCAYYwEQYD\n"
+"VR0fBAowCDAGoASgAoYAMCoGCCsGAQUFBwEBBB4wHDAMBggrBgEFBQcwAoYAMAwG\n"
+"CCsGAQUFBzABhgAwCgYIKoZIzj0EAwIDSAAwRQIhAN3ZYhqu6mVLGidmONsbANk5\n"
+"rzT6aHJcmvj19OxMusaXAiBKy0gBFCri/GLizi4wZo09wf31yZMqfr8IrApvPaLw\n"
+"qA==\n"
+"-----END CERTIFICATE-----\n";
+
+/* Server test-1.unittest.o7s private-public key pair */
+static const char * server_pkp_ec = \
+"-----BEGIN EC PRIVATE KEY-----\n"
+"MHcCAQEEIA4/bcmquVvGrY4+TtfnFSy1SpXs896r5xJjGuD6NmGRoAoGCCqGSM49\n"
+"AwEHoUQDQgAE4BSOhv36q4bCMLSkJaCvzwZ3pPy2M0YzRKFKeV48tG5eD+MBaTrT\n"
+"eoHUcRfpz0EO/inq3FVDzEoAQ2NWpnz0kA==\n"
+"-----END EC PRIVATE KEY-----\n";
+
+/* Public key for the Private key */
+static __attribute__((unused)) const char * server_pk_ec = \
+"-----BEGIN PUBLIC KEY-----\n"
+"MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE4BSOhv36q4bCMLSkJaCvzwZ3pPy2\n"
+"M0YzRKFKeV48tG5eD+MBaTrTeoHUcRfpz0EO/inq3FVDzEoAQ2NWpnz0kA==\n"
+"-----END PUBLIC KEY-----\n";
+
+/* Valid signed server certificate for test-1.unittest.o7s */
+#define SSC_TEXT_SIZE 2295 /* size of cleartext certificate */
+static const char * signed_server_crt_ec = \
+"-----BEGIN CERTIFICATE-----\n"
+"MIIDiTCCAy+gAwIBAgICEAUwCgYIKoZIzj0EAwIwWjELMAkGA1UEBhMCQkUxDDAK\n"
+"BgNVBAgMA09WTDEMMAoGA1UECgwDbzdzMRUwEwYDVQQLDAx1bml0dGVzdC5vN3Mx\n"
+"GDAWBgNVBAMMD2ltLnVuaXR0ZXN0Lm83czAeFw0yNTA4MDgxODQ4NTNaFw00NTA4\n"
+"MDMxODQ4NTNaMG4xCzAJBgNVBAYTAkJFMQwwCgYDVQQIDANPVkwxDjAMBgNVBAcM\n"
+"BUdoZW50MQwwCgYDVQQKDANvN3MxFTATBgNVBAsMDHVuaXR0ZXN0Lm83czEcMBoG\n"
+"A1UEAwwTdGVzdC0xLnVuaXR0ZXN0Lm83czBZMBMGByqGSM49AgEGCCqGSM49AwEH\n"
+"A0IABOAUjob9+quGwjC0pCWgr88Gd6T8tjNGM0ShSnlePLRuXg/jAWk603qB1HEX\n"
+"6c9BDv4p6txVQ8xKAENjVqZ89JCjggHPMIIByzAJBgNVHRMEAjAAMBEGCWCGSAGG\n"
+"+EIBAQQEAwIGQDA4BglghkgBhvhCAQ0EKxYpbzdzIHVuaXR0ZXN0IEdlbmVyYXRl\n"
+"ZCBTZXJ2ZXIgQ2VydGlmaWNhdGUwHQYDVR0OBBYEFI+htsK0xxy6e1CqCyxn7mqi\n"
+"wRrpMIGoBgNVHSMEgaAwgZ2AFMvBqPASDuotJSfpoAa/Zb4di9HroYGApH4wfDEL\n"
+"MAkGA1UEBhMCQkUxDDAKBgNVBAgMA09WTDEOMAwGA1UEBwwFR2hlbnQxDDAKBgNV\n"
+"BAoMA283czEVMBMGA1UECwwMdW5pdHRlc3QubzdzMRgwFgYDVQQDDA9jYS51bml0\n"
+"dGVzdC5vN3MxEDAOBgkqhkiG9w0BCQEWASCCAhADMA4GA1UdDwEB/wQEAwIFoDAT\n"
+"BgNVHSUEDDAKBggrBgEFBQcDATAoBgNVHR8EITAfMB2gG6AZhhdodHRwczovL291\n"
+"cm9ib3Jvcy5yb2NrczBYBggrBgEFBQcBAQRMMEowIwYIKwYBBQUHMAKGF2h0dHBz\n"
+"Oi8vb3Vyb2Jvcm9zLnJvY2tzMCMGCCsGAQUFBzABhhdodHRwczovL291cm9ib3Jv\n"
+"cy5yb2NrczAKBggqhkjOPQQDAgNIADBFAiBZuw/Yb2pq925H7pEiOXr4fMo0wknz\n"
+"ktkxoHAFbjQEPQIhAMInHI7lvRmS0IMw1wBF/WlUZWKvhyU/TeMIZfk/JGCS\n"
+"-----END CERTIFICATE-----\n";
+
+/* Self-signed by server test-1.unittest.o7s using its key */
+static __attribute__((unused)) const char * server_crt_ec = \
+"-----BEGIN CERTIFICATE-----\n"
+"MIIBfjCCASWgAwIBAgIUB5VYxp7i+sgYjvLiwfpf0W5NfqQwCgYIKoZIzj0EAwIw\n"
+"HjEcMBoGA1UEAwwTdGVzdC0xLnVuaXR0ZXN0Lm83czAeFw0yNTA4MDMxOTI4MzVa\n"
+"Fw00NTA3MjkxOTI4MzVaMB4xHDAaBgNVBAMME3Rlc3QtMS51bml0dGVzdC5vN3Mw\n"
+"WTATBgcqhkjOPQIBBggqhkjOPQMBBwNCAATgFI6G/fqrhsIwtKQloK/PBnek/LYz\n"
+"RjNEoUp5Xjy0bl4P4wFpOtN6gdRxF+nPQQ7+KercVUPMSgBDY1amfPSQo0EwPzAe\n"
+"BgNVHREEFzAVghN0ZXN0LTEudW5pdHRlc3QubzdzMB0GA1UdDgQWBBSPobbCtMcc\n"
+"untQqgssZ+5qosEa6TAKBggqhkjOPQQDAgNHADBEAiAoFC/rqgrRXmMUx4y5cPbv\n"
+"jOKpoL3FpehRgGkPatmL/QIgMRHc2TSGo6q1SG22Xt1dHAIBsaN2AlSfhjKULMH5\n"
+"gRo=\n"
+"-----END CERTIFICATE-----\n";
+
+#endif /* TEST_CERTS_H */
+