Give SHA256 functions C bindings

1 files changed, 65 insertions, 0 deletions

diff --git a/include/olm/crypto.h b/include/olm/crypto.h
new file mode 100644
index 0000000..1357834
--- /dev/null
+++ b/include/olm/crypto.h
@@ -0,0 +1,65 @@
+/* Copyright 2015 OpenMarket Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* C-compatible crpyto utility functions. At some point all of crypto.hh will
+ * move here.
+ */
+
+#ifndef OLM_CRYPTO_H_
+#define OLM_CRYPTO_H_
+
+#include <stdint.h>
+#include <stdlib.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+const size_t SHA256_OUTPUT_LENGTH = 32;
+
+/** Computes SHA-256 of the input. The output buffer must be a least 32
+ * bytes long. */
+void crypto_sha256(
+    uint8_t const * input, size_t input_length,
+    uint8_t * output
+);
+
+/** HMAC: Keyed-Hashing for Message Authentication
+ * http://tools.ietf.org/html/rfc2104
+ * Computes HMAC-SHA-256 of the input for the key. The output buffer must
+ * be at least 32 bytes long. */
+void crypto_hmac_sha256(
+    uint8_t const * key, size_t key_length,
+    uint8_t const * input, size_t input_length,
+    uint8_t * output
+);
+
+
+/** HMAC-based Key Derivation Function (HKDF)
+ * https://tools.ietf.org/html/rfc5869
+ * Derives key material from the input bytes. */
+void crypto_hkdf_sha256(
+    uint8_t const * input, size_t input_length,
+    uint8_t const * info, size_t info_length,
+    uint8_t const * salt, size_t salt_length,
+    uint8_t * output, size_t output_length
+);
+
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif /* OLM_CRYPTO_H_ */