X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=src%2Futil%2Fcrypto_hash.c;h=af492e15e021ff5d861d7f26df91d561308cbe7c;hb=8226d9807819dbbc4b05751f4cdd09603832367d;hp=74ea72de4e442da826030eec0edc6e09347b4943;hpb=200aaa0dd6813f19eb7ed67a0fdc301d091fc2d7;p=oweals%2Fgnunet.git

diff --git a/src/util/crypto_hash.c b/src/util/crypto_hash.c
index 74ea72de4..af492e15e 100644
--- a/src/util/crypto_hash.c
+++ b/src/util/crypto_hash.c
@@ -668,8 +668,10 @@ GNUNET_CRYPTO_hash_from_string (const char *enc, GNUNET_HashCode * result)
  * fast, not involve bits[0] or bits[4] (they're used elsewhere), and be
  * somewhat consistent. And of course, the result should be a positive
  * number.
- *
- * @returns a positive number which is a measure for
+ * 
+ * @param a some hash code
+ * @param b some hash code
+ * @return a positive number which is a measure for
  *  hashcode proximity.
  */
 unsigned int
@@ -806,4 +808,43 @@ GNUNET_CRYPTO_hash_xorcmp (const GNUNET_HashCode * h1,
   return 0;
 }
 
+
+/**
+ * Calculate HMAC of a message (RFC 2104)
+ *
+ * @param key secret key
+ * @param plaintext input plaintext
+ * @param plaintext_len length of plaintext
+ * @param hmac where to store the hmac
+ */
+void 
+GNUNET_CRYPTO_hmac (const struct GNUNET_CRYPTO_AesSessionKey *key,
+		    const void *plaintext,
+		    size_t plaintext_len,
+		    GNUNET_HashCode *hmac)
+{
+  GNUNET_HashCode kh;
+  GNUNET_HashCode ipad;
+  GNUNET_HashCode opad;
+  GNUNET_HashCode him;
+  struct sha512_ctx sctx;
+
+  memset (&kh, 0, sizeof (kh));
+  GNUNET_assert (sizeof (GNUNET_HashCode) > sizeof (struct GNUNET_CRYPTO_AesSessionKey));
+  memcpy (&kh, key, sizeof (struct GNUNET_CRYPTO_AesSessionKey));				
+  memset (&ipad, 0x5c, sizeof (ipad));
+  memset (&opad, 0x36, sizeof (opad));
+  GNUNET_CRYPTO_hash_xor (&ipad, &kh, &ipad);
+  GNUNET_CRYPTO_hash_xor (&opad, &kh, &opad);
+  sha512_init (&sctx);
+  sha512_update (&sctx, (const unsigned char*) &ipad, sizeof (ipad));
+  sha512_update (&sctx, plaintext, plaintext_len);
+  sha512_final (&sctx, (unsigned char*) &him);
+  sha512_init (&sctx);
+  sha512_update (&sctx, (const unsigned char*) &opad, sizeof (opad));
+  sha512_update (&sctx, (const unsigned char*) &him, sizeof (him));
+  sha512_final (&sctx, (unsigned char*) hmac);
+}
+
+
 /* end of crypto_hash.c */