Finish and test crypto primitives

3 files changed, 174 insertions, 27 deletions

diff --git a/include/axolotl/crypto.hh b/include/axolotl/crypto.hh
index 9691228..3f7b71e 100644
--- a/include/axolotl/crypto.hh
+++ b/include/axolotl/crypto.hh
@@ -19,7 +19,7 @@ Curve25519KeyPair generate_key(
 );
 
 
-const std::size_t CURVE25519_SHARED_SECRET_LENGTH = 16;
+const std::size_t CURVE25519_SHARED_SECRET_LENGTH = 32;
 
 
 void curve25519_shared_secret(
@@ -68,6 +68,12 @@ void aes_decrypt_cbc(
 );
 
 
+void sha256(
+    std::uint8_t const * input, std::size_t input_length,
+    std::uint8_t * output
+);
+
+
 const std::size_t HMAC_SHA256_OUTPUT_LENGTH = 32;
 
 
diff --git a/src/crypto.cpp b/src/crypto.cpp
index c1ef88a..5277b86 100644
--- a/src/crypto.cpp
+++ b/src/crypto.cpp
@@ -19,7 +19,8 @@ namespace {
 
 static const std::uint8_t CURVE25519_BASEPOINT[32] = {9};
 static const std::size_t AES_BLOCK_LENGTH = 16;
-static const std::size_t SHA256_BLOCK_LENGTH = 32;
+static const std::size_t SHA256_HASH_LENGTH = 32;
+static const std::size_t SHA256_BLOCK_LENGTH = 64;
 static const std::uint8_t HKDF_DEFAULT_SALT[32] = {};
 
 template<std::size_t block_size>
@@ -37,13 +38,13 @@ inline static void hmac_sha256_key(
     std::uint8_t const * input_key, std::size_t input_key_length,
     std::uint8_t * hmac_key
 ) {
+    std::memset(hmac_key, 0, SHA256_BLOCK_LENGTH);
     if (input_key_length > SHA256_BLOCK_LENGTH) {
         ::SHA256_CTX context;
         ::sha256_init(&context);
         ::sha256_update(&context, input_key, input_key_length);
         ::sha256_final(&context, hmac_key);
     } else {
-        std::memset(hmac_key, 0, SHA256_BLOCK_LENGTH);
         std::memcpy(hmac_key, input_key, input_key_length);
     }
 }
@@ -56,7 +57,7 @@ inline void hmac_sha256_init(
     std::uint8_t i_pad[SHA256_BLOCK_LENGTH];
     std::memcpy(i_pad, hmac_key, SHA256_BLOCK_LENGTH);
     for (std::size_t i = 0; i < SHA256_BLOCK_LENGTH; ++i) {
-        i_pad[i] ^= 0x5C;
+        i_pad[i] ^= 0x36;
     }
     ::sha256_init(context);
     ::sha256_update(context, i_pad, SHA256_BLOCK_LENGTH);
@@ -69,16 +70,15 @@ inline void hmac_sha256_final(
     std::uint8_t const * hmac_key,
     std::uint8_t * output
 ) {
-    std::uint8_t o_pad[SHA256_BLOCK_LENGTH];
+    std::uint8_t o_pad[SHA256_BLOCK_LENGTH + SHA256_HASH_LENGTH];
     std::memcpy(o_pad, hmac_key, SHA256_BLOCK_LENGTH);
     for (std::size_t i = 0; i < SHA256_BLOCK_LENGTH; ++i) {
-        o_pad[i] ^= 0x36;
+        o_pad[i] ^= 0x5C;
     }
+    ::sha256_final(context, o_pad + SHA256_BLOCK_LENGTH);
     ::SHA256_CTX final_context;
     ::sha256_init(&final_context);
-    ::sha256_update(&final_context, o_pad, SHA256_BLOCK_LENGTH);
-    ::sha256_final(context, o_pad);
-    ::sha256_update(&final_context, o_pad, SHA256_BLOCK_LENGTH);
+    ::sha256_update(&final_context, o_pad, sizeof(o_pad));
     ::sha256_final(&final_context, output);
     std::memset(o_pad, 0, sizeof(o_pad));
 }
@@ -167,6 +167,16 @@ void axolotl::aes_decrypt_cbc(
 }
 
 
+void axolotl::sha256(
+    std::uint8_t const * input, std::size_t input_length,
+    std::uint8_t * output
+) {
+    ::SHA256_CTX context;
+    ::sha256_init(&context);
+    ::sha256_update(&context, input, input_length);
+    ::sha256_final(&context, output);
+}
+
 void axolotl::hmac_sha256(
     std::uint8_t const * key, std::size_t key_length,
     std::uint8_t const * input, std::size_t input_length,
@@ -184,14 +194,13 @@ void axolotl::hmac_sha256(
 
 void axolotl::hkdf_sha256(
     std::uint8_t const * input, std::size_t input_length,
-    std::uint8_t const * info, std::size_t info_length,
     std::uint8_t const * salt, std::size_t salt_length,
+    std::uint8_t const * info, std::size_t info_length,
     std::uint8_t * output, std::size_t output_length
 ) {
     ::SHA256_CTX context;
-    std::uint8_t extract_key[SHA256_BLOCK_LENGTH];
-    std::uint8_t expand_key[SHA256_BLOCK_LENGTH];
-    std::uint8_t step_result[SHA256_BLOCK_LENGTH];
+    std::uint8_t hmac_key[SHA256_BLOCK_LENGTH];
+    std::uint8_t step_result[SHA256_HASH_LENGTH];
     std::size_t bytes_remaining = output_length;
     std::uint8_t iteration = 1;
     if (!salt) {
@@ -199,25 +208,27 @@ void axolotl::hkdf_sha256(
         salt_length = sizeof(HKDF_DEFAULT_SALT);
     }
     /* Expand */
-    hmac_sha256_key(salt, salt_length, extract_key);
-    hmac_sha256_init(&context, extract_key);
+    hmac_sha256_key(salt, salt_length, hmac_key);
+    hmac_sha256_init(&context, hmac_key);
     ::sha256_update(&context, input, input_length);
-    hmac_sha256_final(&context, extract_key, expand_key);
+    hmac_sha256_final(&context, hmac_key, step_result);
+    hmac_sha256_key(step_result, SHA256_HASH_LENGTH, hmac_key);
+
     /* Extract */
-    hmac_sha256_init(&context, expand_key);
+    hmac_sha256_init(&context, hmac_key);
     ::sha256_update(&context, info, info_length);
     ::sha256_update(&context, &iteration, 1);
-    hmac_sha256_final(&context, expand_key, step_result);
-    while (bytes_remaining > SHA256_BLOCK_LENGTH) {
-        std::memcpy(output, step_result, SHA256_BLOCK_LENGTH);
-        output += SHA256_BLOCK_LENGTH;
-        bytes_remaining -= SHA256_BLOCK_LENGTH;
+    hmac_sha256_final(&context, hmac_key, step_result);
+    while (bytes_remaining > SHA256_HASH_LENGTH) {
+        std::memcpy(output, step_result, SHA256_HASH_LENGTH);
+        output += SHA256_HASH_LENGTH;
+        bytes_remaining -= SHA256_HASH_LENGTH;
         iteration ++;
-        hmac_sha256_init(&context, expand_key);
-        ::sha256_update(&context, step_result, SHA256_BLOCK_LENGTH);
+        hmac_sha256_init(&context, hmac_key);
+        ::sha256_update(&context, step_result, SHA256_HASH_LENGTH);
         ::sha256_update(&context, info, info_length);
         ::sha256_update(&context, &iteration, 1);
-        hmac_sha256_final(&context, expand_key, step_result);
+        hmac_sha256_final(&context, hmac_key, step_result);
     }
     std::memcpy(output, step_result, bytes_remaining);
 }
diff --git a/tests/test_crypto.cpp b/tests/test_crypto.cpp
index ed50905..d6e282f 100644
--- a/tests/test_crypto.cpp
+++ b/tests/test_crypto.cpp
@@ -36,7 +36,137 @@ void assert_equals(
 int main() {
 
 
+{ /* Curve25529 Test Case 1 */
 
+TEST_CASE = "Curve25529 Test Case 1";
+
+std::uint8_t alice_private[32] = {
+    0x77, 0x07, 0x6D, 0x0A, 0x73, 0x18, 0xA5, 0x7D,
+    0x3C, 0x16, 0xC1, 0x72, 0x51, 0xB2, 0x66, 0x45,
+    0xDF, 0x4C, 0x2F, 0x87, 0xEB, 0xC0, 0x99, 0x2A,
+    0xB1, 0x77, 0xFB, 0xA5, 0x1D, 0xB9, 0x2C, 0x2A
+};
+
+std::uint8_t alice_public[32] = {
+    0x85, 0x20, 0xF0, 0x09, 0x89, 0x30, 0xA7, 0x54,
+    0x74, 0x8B, 0x7D, 0xDC, 0xB4, 0x3E, 0xF7, 0x5A,
+    0x0D, 0xBF, 0x3A, 0x0D, 0x26, 0x38, 0x1A, 0xF4,
+    0xEB, 0xA4, 0xA9, 0x8E, 0xAA, 0x9B, 0x4E, 0x6A
+};
+
+std::uint8_t bob_private[32] = {
+    0x5D, 0xAB, 0x08, 0x7E, 0x62, 0x4A, 0x8A, 0x4B,
+    0x79, 0xE1, 0x7F, 0x8B, 0x83, 0x80, 0x0E, 0xE6,
+    0x6F, 0x3B, 0xB1, 0x29, 0x26, 0x18, 0xB6, 0xFD,
+    0x1C, 0x2F, 0x8B, 0x27, 0xFF, 0x88, 0xE0, 0xEB
+};
+
+std::uint8_t bob_public[32] = {
+    0xDE, 0x9E, 0xDB, 0x7D, 0x7B, 0x7D, 0xC1, 0xB4,
+    0xD3, 0x5B, 0x61, 0xC2, 0xEC, 0xE4, 0x35, 0x37,
+    0x3F, 0x83, 0x43, 0xC8, 0x5B, 0x78, 0x67, 0x4D,
+    0xAD, 0xFC, 0x7E, 0x14, 0x6F, 0x88, 0x2B, 0x4F
+};
+
+std::uint8_t expected_agreement[32] = {
+    0x4A, 0x5D, 0x9D, 0x5B, 0xA4, 0xCE, 0x2D, 0xE1,
+    0x72, 0x8E, 0x3B, 0xF4, 0x80, 0x35, 0x0F, 0x25,
+    0xE0, 0x7E, 0x21, 0xC9, 0x47, 0xD1, 0x9E, 0x33,
+    0x76, 0xF0, 0x9B, 0x3C, 0x1E, 0x16, 0x17, 0x42
+};
+
+axolotl::Curve25519KeyPair alice_pair = axolotl::generate_key(alice_private);
+
+assert_equals(alice_private, alice_pair.private_key, 32);
+assert_equals(alice_public, alice_pair.public_key, 32);
+
+axolotl::Curve25519KeyPair bob_pair = axolotl::generate_key(bob_private);
+
+assert_equals(bob_private, bob_pair.private_key, 32);
+assert_equals(bob_public, bob_pair.public_key, 32);
+
+std::uint8_t actual_agreement[axolotl::CURVE25519_SHARED_SECRET_LENGTH] = {};
+
+axolotl::curve25519_shared_secret(alice_pair, bob_pair, actual_agreement);
+
+assert_equals(expected_agreement, actual_agreement, 32);
+
+axolotl::curve25519_shared_secret(bob_pair, alice_pair, actual_agreement);
+
+assert_equals(expected_agreement, actual_agreement, 32);
+
+} /* Curve25529 Test Case 1 */
+
+
+{ /* AES Test Case 1 */
+
+TEST_CASE = "AES Test Case 1";
+
+axolotl::Aes256Key key = {};
+axolotl::Aes256Iv iv = {};
+std::uint8_t input[32] = {};
+
+std::uint8_t expected[32] = {
+    0xDC, 0x95, 0xC0, 0x78, 0xA2, 0x40, 0x89, 0x89,
+    0xAD, 0x48, 0xA2, 0x14, 0x92, 0x84, 0x20, 0x87,
+    0x08, 0xC3, 0x74, 0x84, 0x8C, 0x22, 0x82, 0x33,
+    0xC2, 0xB3, 0x4F, 0x33, 0x2B, 0xD2, 0xE9, 0xD3
+};
+
+std::uint8_t actual[32] = {};
+
+axolotl::aes_encrypt_cbc(key, iv, input, sizeof(input), actual);
+
+assert_equals(expected, actual, 32);
+
+axolotl::aes_decrypt_cbc(key, iv, expected, sizeof(expected), actual);
+
+assert_equals(input, actual, 32);
+
+} /* AES Test Case 1 */
+
+
+{ /* SHA 256 Test Case 1 */
+
+TEST_CASE = "SHA 256 Test Case 1";
+
+std::uint8_t input[0] = {};
+
+std::uint8_t expected[32] = {
+    0xE3, 0xB0, 0xC4, 0x42, 0x98, 0xFC, 0x1C, 0x14,
+    0x9A, 0xFB, 0xF4, 0xC8, 0x99, 0x6F, 0xB9, 0x24,
+    0x27, 0xAE, 0x41, 0xE4, 0x64, 0x9B, 0x93, 0x4C,
+    0xA4, 0x95, 0x99, 0x1B, 0x78, 0x52, 0xB8, 0x55
+};
+
+std::uint8_t actual[32];
+
+axolotl::sha256(input, sizeof(input), actual);
+
+assert_equals(expected, actual, 32);
+
+} /* SHA 256 Test Case 1 */
+
+{ /* HMAC Test Case 1 */
+
+TEST_CASE = "HMAC Test Case 1";
+
+std::uint8_t input[0] = {};
+
+std::uint8_t expected[32] = {
+    0xb6, 0x13, 0x67, 0x9a, 0x08, 0x14, 0xd9, 0xec,
+    0x77, 0x2f, 0x95, 0xd7, 0x78, 0xc3, 0x5f, 0xc5,
+    0xff, 0x16, 0x97, 0xc4, 0x93, 0x71, 0x56, 0x53,
+    0xc6, 0xc7, 0x12, 0x14, 0x42, 0x92, 0xc5, 0xad
+};
+
+std::uint8_t actual[32];
+
+axolotl::hmac_sha256(input, sizeof(input), input, sizeof(input), actual);
+
+assert_equals(expected, actual, 32);
+
+} /* HMAC Test Case 1 */
 
 { /* HDKF Test Case 1 */
 
@@ -68,8 +198,8 @@ std::uint8_t hmac_expected_output[32] = {
 std::uint8_t hmac_actual_output[32] = {};
 
 axolotl::hmac_sha256(
-    salt, 0 * sizeof(salt),
-    input, 0 * sizeof(input),
+    salt, sizeof(salt),
+    input, sizeof(input),
     hmac_actual_output
 );