initial commit: start implementing the crypto primitives

1 files changed, 88 insertions, 0 deletions

diff --git a/include/axolotl/crypto.hh b/include/axolotl/crypto.hh
new file mode 100644
index 0000000..9691228
--- /dev/null
+++ b/include/axolotl/crypto.hh
@@ -0,0 +1,88 @@
+#include <cstdint>
+
+namespace axolotl {
+
+
+struct Curve25519PublicKey {
+    static const int LENGTH = 32;
+    std::uint8_t public_key[32];
+};
+
+
+struct Curve25519KeyPair : public Curve25519PublicKey {
+    std::uint8_t private_key[32];
+};
+
+
+Curve25519KeyPair generate_key(
+    std::uint8_t const * random_32_bytes
+);
+
+
+const std::size_t CURVE25519_SHARED_SECRET_LENGTH = 16;
+
+
+void curve25519_shared_secret(
+    Curve25519KeyPair const & our_key,
+    Curve25519PublicKey const & their_key,
+    std::uint8_t * output
+);
+
+
+struct Aes256Key {
+    static const int LENGTH = 32;
+    std::uint8_t key[32];
+};
+
+
+struct Aes256Iv {
+    static const int LENGTH = 16;
+    std::uint8_t iv[16];
+};
+
+
+std::size_t aes_pkcs_7_padded_length(
+    std::size_t input_length
+);
+
+
+void aes_pkcs_7_padding(
+    std::uint8_t const * input, std::size_t input_length,
+    std::uint8_t * output
+);
+
+
+void aes_encrypt_cbc(
+    Aes256Key const & key,
+    Aes256Iv const & iv,
+    std::uint8_t const * input, std::size_t input_length,
+    std::uint8_t * output
+);
+
+
+void aes_decrypt_cbc(
+    Aes256Key const & key,
+    Aes256Iv const & iv,
+    std::uint8_t const * input, std::size_t input_length,
+    std::uint8_t * output
+);
+
+
+const std::size_t HMAC_SHA256_OUTPUT_LENGTH = 32;
+
+
+void hmac_sha256(
+    std::uint8_t const * key, std::size_t key_length,
+    std::uint8_t const * input, std::size_t input_length,
+    std::uint8_t * output
+);
+
+
+void 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 * output, std::size_t output_length
+);
+
+} // namespace axolotl