X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=crypt.h;h=21abe41f68cd8c5b335cc133b5c6f3050869c4ee;hp=0e0695e574ecbfcb6dd4c5491fa2f499329a8d14;hb=e7593d7c153bfca2131b18621fb24ae18c1c0cb3;hpb=a5ec1a6f44b149c0b018c1da8c1703109c5bdc8c

diff --git a/crypt.h b/crypt.h
index 0e0695e5..21abe41f 100644
--- a/crypt.h
+++ b/crypt.h
@@ -60,3 +60,52 @@ int sc_recv_buffer(struct stream_cipher_context *scc, char *buf, size_t size);
 #define LOAD_PRIVATE_KEY 1
 #define CHALLENGE_SIZE 64
 /** \endcond **/
+
+/** Size of the hash value in bytes. */
+#define HASH_SIZE 20
+
+void hash_function(const char *data, unsigned long len, unsigned char *hash);
+
+/**
+ * Compare two hashes.
+ *
+ * \param h1 Pointer to the first hash value.
+ * \param h2 Pointer to the second hash value.
+ *
+ * \return 1, -1, or zero, depending on whether \a h1 is greater than,
+ * less than or equal to h2, respectively.
+ */
+_static_inline_ int hash_compare(unsigned char *h1, unsigned char *h2)
+{
+	int i;
+
+	for (i = 0; i < HASH_SIZE; i++) {
+		if (h1[i] < h2[i])
+			return -1;
+		if (h1[i] > h2[i])
+			return 1;
+	}
+	return 0;
+}
+
+/**
+ * Convert a hash value to ascii format.
+ *
+ * \param hash the hash value.
+ * \param asc Result pointer.
+ *
+ * \a asc must point to an area of at least 2 * \p HASH_SIZE + 1 bytes which
+ * will be filled by the function with the ascii representation of the hash
+ * value given by \a hash, and a terminating \p NULL byte.
+ */
+_static_inline_ void hash_to_asc(unsigned char *hash, char *asc)
+{
+	int i;
+	const char hexchar[] = "0123456789abcdef";
+
+	for (i = 0; i < HASH_SIZE; i++) {
+		asc[2 * i] = hexchar[hash[i] >> 4];
+		asc[2 * i + 1] = hexchar[hash[i] & 0xf];
+	}
+	asc[2 * HASH_SIZE] = '\0';
+}