Add ML-KEM 768 from BoringSSL

Changes include conversion from C++, basic KNF, then adaptation to
use our sha3 functions for sha3 and shake instead of the BorinSSL
version. This Adds units tests to run against BoringSSL and NIST test
vectors.

The future public API is the same as Boring's - but is not yet exposed
pending making bytesring.h public (which will happen separately) and
a minor bump

Currently this will just ensure we build and run regress.

ok tb@ to get it into the tree and massage from there.

1 files changed, 157 insertions, 0 deletions

diff --git a/src/regress/lib/libcrypto/mlkem/mlkem768_iteration_test.c b/src/regress/lib/libcrypto/mlkem/mlkem768_iteration_test.c
new file mode 100644
index 0000000000..4df8171273
--- /dev/null
+++ b/src/regress/lib/libcrypto/mlkem/mlkem768_iteration_test.c
@@ -0,0 +1,157 @@
+/* Copyright (c) 2024, Google Inc.
+ * Copyright (c) 2024, Bob Beck <beck@obtuse.com>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "bytestring.h"
+
+#include "sha3_internal.h"
+#include "mlkem.h"
+#include "mlkem_internal.h"
+#include "mlkem_tests_util.h"
+
+static int
+encode_private_key(const struct MLKEM768_private_key *priv, uint8_t **out_buf,
+    size_t *out_len)
+{
+        CBB cbb;
+        if (!CBB_init(&cbb, MLKEM768_PUBLIC_KEY_BYTES))
+                return 0;
+        if (!MLKEM768_marshal_private_key(&cbb, priv))
+                return 0;
+        if (!CBB_finish(&cbb, out_buf, out_len))
+                return 0;
+        CBB_cleanup(&cbb);
+        return 1;
+}
+
+/*
+ * The structure of this test is taken from
+ *  https://github.com/C2SP/CCTV/blob/main/ML-KEM/README.md?ref=words.filippo.io#accumulated-pq-crystals-vectors
+ *  but the final value has been updated to reflect the change from Kyber to
+ *  ML-KEM.
+ *
+ * The deterministic RNG is a single SHAKE-128 instance with an empty input.
+ * (The RNG stream starts with 7f9c2ba4e88f827d616045507605853e.)
+ */
+
+static void
+MlkemIterativeTest()
+{
+        /* https://github.com/C2SP/CCTV/tree/main/ML-KEM */
+        /*
+         * The deterministic RNG is a single SHAKE-128 instance with an empty input.
+         * (The RNG stream starts with 7f9c2ba4e88f827d616045507605853e.)
+         */
+        const uint8_t kExpectedSeedStart[16] = {
+                0x7f, 0x9c, 0x2b, 0xa4, 0xe8, 0x8f, 0x82, 0x7d, 0x61, 0x60, 0x45,
+                0x50, 0x76, 0x05, 0x85, 0x3e
+        };
+        /*
+         * Filippo says:
+         * ML-KEM-768: f7db260e1137a742e05fe0db9525012812b004d29040a5b606aad3d134b548d3
+         * but Boring believes this:
+         */
+        const uint8_t kExpectedAdam[32] = {
+                0xf9, 0x59, 0xd1, 0x8d, 0x3d, 0x11, 0x80, 0x12, 0x14, 0x33, 0xbf,
+                0x0e, 0x05, 0xf1, 0x1e, 0x79, 0x08, 0xcf, 0x9d, 0x03, 0xed, 0xc1,
+                0x50, 0xb2, 0xb0, 0x7c, 0xb9, 0x0b, 0xef, 0x5b, 0xc1, 0xc1
+        };
+        uint8_t encoded_public_key[MLKEM768_PUBLIC_KEY_BYTES];
+        uint8_t invalid_ciphertext[MLKEM768_CIPHERTEXT_BYTES];
+        uint8_t shared_secret[MLKEM_SHARED_SECRET_BYTES];
+        uint8_t ciphertext[MLKEM768_CIPHERTEXT_BYTES];
+        uint8_t encap_entropy[MLKEM_ENCAP_ENTROPY];
+        uint8_t seed[MLKEM_SEED_BYTES] = {0};
+        struct MLKEM768_private_key priv;
+        struct MLKEM768_public_key pub;
+        sha3_ctx drng, results;
+        uint8_t out[32];
+        int i;
+
+        shake128_init(&drng);
+        shake128_init(&results);
+
+        shake_xof(&drng);
+        for (i = 0; i < 10000; i++) {
+                uint8_t *encoded_private_key = NULL;
+                size_t encoded_private_key_len;
+
+                /*
+                 * This should draw both d and z from DRNG concatenating in
+                 * seed.
+                 */
+                shake_out(&drng, seed, sizeof(seed));
+                if (i == 0) {
+                        TEST_DATAEQ(seed, kExpectedSeedStart,
+                            sizeof(kExpectedSeedStart), "seed start");
+                }
+
+                /* generate ek as encoded_public_key */
+                MLKEM768_generate_key_external_entropy(encoded_public_key,
+                    &priv, seed);
+                MLKEM768_public_from_private(&pub, &priv);
+
+                /* hash in ek */
+                shake_update(&results, encoded_public_key,
+                    sizeof(encoded_public_key));
+
+                /* marshal priv to dk as encoded_private_key */
+                TEST(!encode_private_key(&priv, &encoded_private_key,
+                    &encoded_private_key_len), "encode_private_key");
+
+                /* hash in dk */
+                shake_update(&results, encoded_private_key,
+                    encoded_private_key_len);
+
+                free(encoded_private_key);
+
+                /* draw m as encap entropy from DRNG */
+                shake_out(&drng, encap_entropy, sizeof(encap_entropy));
+
+                /* generate ct as ciphertext, k as shared_secret */
+                MLKEM768_encap_external_entropy(ciphertext, shared_secret,
+                    &pub, encap_entropy);
+
+                /* hash in ct */
+                shake_update(&results, ciphertext, sizeof(ciphertext));
+                /* hash in k */
+                shake_update(&results, shared_secret, sizeof(shared_secret));
+
+                /* draw ct as invalid_ciphertxt from DRNG */
+                shake_out(&drng, invalid_ciphertext,
+                    sizeof(invalid_ciphertext));
+
+                /* generte k as shared secret from invalid ciphertext */
+                TEST(!MLKEM768_decap(shared_secret, invalid_ciphertext,
+                    sizeof(invalid_ciphertext), &priv), "decap failed!");
+
+                /* hash in k */
+                shake_update(&results, shared_secret, sizeof(shared_secret));
+        }
+        shake_xof(&results);
+        shake_out(&results, out, 32);
+
+        TEST_DATAEQ(out, kExpectedAdam, 32, "final result hash");
+}
+
+int
+main(int argc, char **argv)
+{
+        MlkemIterativeTest();
+        exit(failure);
+}