1 files changed, 103 insertions, 0 deletions
diff --git a/src/crypto.h b/src/crypto.h
new file mode 100644
index 0000000..0ac23f9
--- /dev/null
+++ b/src/crypto.h
@@ -0,0 +1,103 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2015-2021 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#ifndef _WG_CRYPTO
+#define _WG_CRYPTO
+
+#include <sys/types.h>
+
+enum chacha20poly1305_lengths {
+	XCHACHA20POLY1305_NONCE_SIZE = 24,
+	CHACHA20POLY1305_KEY_SIZE = 32,
+	CHACHA20POLY1305_AUTHTAG_SIZE = 16
+};
+
+void
+chacha20poly1305_encrypt(uint8_t *dst, const uint8_t *src, const size_t src_len,
+			 const uint8_t *ad, const size_t ad_len,
+			 const uint64_t nonce,
+			 const uint8_t key[CHACHA20POLY1305_KEY_SIZE]);
+
+bool
+chacha20poly1305_decrypt(uint8_t *dst, const uint8_t *src, const size_t src_len,
+			 const uint8_t *ad, const size_t ad_len,
+			 const uint64_t nonce,
+			 const uint8_t key[CHACHA20POLY1305_KEY_SIZE]);
+
+void
+xchacha20poly1305_encrypt(uint8_t *dst, const uint8_t *src,
+			  const size_t src_len, const uint8_t *ad,
+			  const size_t ad_len,
+			  const uint8_t nonce[XCHACHA20POLY1305_NONCE_SIZE],
+			  const uint8_t key[CHACHA20POLY1305_KEY_SIZE]);
+
+bool
+xchacha20poly1305_decrypt(uint8_t *dst, const uint8_t *src,
+			  const size_t src_len,  const uint8_t *ad,
+			  const size_t ad_len,
+			  const uint8_t nonce[XCHACHA20POLY1305_NONCE_SIZE],
+			  const uint8_t key[CHACHA20POLY1305_KEY_SIZE]);
+
+
+enum blake2s_lengths {
+	BLAKE2S_BLOCK_SIZE = 64,
+	BLAKE2S_HASH_SIZE = 32,
+	BLAKE2S_KEY_SIZE = 32
+};
+
+struct blake2s_state {
+	uint32_t h[8];
+	uint32_t t[2];
+	uint32_t f[2];
+	uint8_t buf[BLAKE2S_BLOCK_SIZE];
+	unsigned int buflen;
+	unsigned int outlen;
+};
+
+void blake2s_init(struct blake2s_state *state, const size_t outlen);
+
+void blake2s_init_key(struct blake2s_state *state, const size_t outlen,
+		      const uint8_t *key, const size_t keylen);
+
+void blake2s_update(struct blake2s_state *state, const uint8_t *in, size_t inlen);
+
+void blake2s_final(struct blake2s_state *state, uint8_t *out);
+
+void blake2s(uint8_t *out, const uint8_t *in, const uint8_t *key,
+	     const size_t outlen, const size_t inlen, const size_t keylen);
+
+void blake2s_hmac(uint8_t *out, const uint8_t *in, const uint8_t *key,
+		  const size_t outlen, const size_t inlen, const size_t keylen);
+
+enum curve25519_lengths {
+        CURVE25519_KEY_SIZE = 32
+};
+
+bool curve25519(uint8_t mypublic[static CURVE25519_KEY_SIZE],
+		const uint8_t secret[static CURVE25519_KEY_SIZE],
+		const uint8_t basepoint[static CURVE25519_KEY_SIZE]);
+
+static inline bool
+curve25519_generate_public(uint8_t pub[static CURVE25519_KEY_SIZE],
+			   const uint8_t secret[static CURVE25519_KEY_SIZE])
+{
+	static const uint8_t basepoint[CURVE25519_KEY_SIZE] = { 9 };
+
+	return curve25519(pub, secret, basepoint);
+}
+
+static inline void curve25519_clamp_secret(uint8_t secret[static CURVE25519_KEY_SIZE])
+{
+        secret[0] &= 248;
+        secret[31] = (secret[31] & 127) | 64;
+}
+
+static inline void curve25519_generate_secret(uint8_t secret[CURVE25519_KEY_SIZE])
+{
+	arc4random_buf(secret, CURVE25519_KEY_SIZE);
+	curve25519_clamp_secret(secret);
+}
+
+#endif