Add the RFC6979 PRNG

1 files changed, 36 insertions, 0 deletions

diff --git a/src/crypto/rfc6979_hmac_sha256.h b/src/crypto/rfc6979_hmac_sha256.h
new file mode 100644
index 0000000000..e67ddcf8fe
--- /dev/null
+++ b/src/crypto/rfc6979_hmac_sha256.h
@@ -0,0 +1,36 @@
+// Copyright (c) 2014 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_RFC6979_HMAC_SHA256_H
+#define BITCOIN_RFC6979_HMAC_SHA256_H
+
+#include "crypto/hmac_sha256.h"
+
+#include <stdint.h>
+#include <stdlib.h>
+
+/** The RFC 6979 PRNG using HMAC-SHA256. */
+class RFC6979_HMAC_SHA256
+{
+private:
+    unsigned char V[CHMAC_SHA256::OUTPUT_SIZE];
+    unsigned char K[CHMAC_SHA256::OUTPUT_SIZE];
+    bool retry;
+
+public:
+    /**
+     * Construct a new RFC6979 PRNG, using the given key and message.
+     * The message is assumed to be already hashed.
+     */
+    RFC6979_HMAC_SHA256(const unsigned char* key, size_t keylen, const unsigned char* msg, size_t msglen);
+
+    /**
+     * Generate a byte array.
+     */
+    void Generate(unsigned char* output, size_t outputlen);
+
+    ~RFC6979_HMAC_SHA256();
+};
+
+#endif // BITCOIN_RFC6979_HMAC_SHA256_H