diff --git a/sha1.h b/sha.h
similarity index 62%
rename from sha1.h
rename to sha.h
index ab1a88b3b19874933244004b3c5af35d86d3bc6a..0cf9b8ca860e4402ee1b5c54cbc66f08de2e1a7f 100644
--- a/sha1.h
+++ b/sha.h
@@ -1,6 +1,6 @@
-/* sha1.h
+/* sha.h
  *
- * The sha1 hash function.
+ * The sha1 and sha256 hash functions.
  */
 
 /* nettle, low-level cryptographics library
@@ -23,15 +23,17 @@
  * MA 02111-1307, USA.
  */
  
-#ifndef NETTLE_SHA1_H_INCLUDED
-#define NETTLE_SHA1_H_INCLUDED
+#ifndef NETTLE_SHA_H_INCLUDED
+#define NETTLE_SHA_H_INCLUDED
 
 #include <inttypes.h>
 
+/* SHA1 */
+
 #define SHA1_DIGEST_SIZE 20
 #define SHA1_DATA_SIZE 64
 
-/* Digest is kept internally as 4 32-bit words. */
+/* Digest is kept internally as 5 32-bit words. */
 #define _SHA1_DIGEST_LENGTH 5
 
 struct sha1_ctx
@@ -58,4 +60,37 @@ sha1_digest(const struct sha1_ctx *ctx,
 	    unsigned length,
 	    uint8_t *digest);
 
-#endif /* NETTLE_SHA1_H_INCLUDED */
+/* SHA256 */
+
+#define SHA256_DIGEST_SIZE 32
+#define SHA256_DATA_SIZE 64
+
+/* Digest is kept internally as 8 32-bit words. */
+#define _SHA256_DIGEST_LENGTH 8
+
+struct sha256_ctx
+{
+  uint32_t state[_SHA256_DIGEST_LENGTH];    /* State variables */
+  uint32_t count_low, count_high;           /* 64-bit block count */
+  uint8_t block[SHA256_DATA_SIZE];          /* SHA256 data buffer */
+  unsigned int index;                       /* index into buffer */
+};
+
+void
+sha256_init(struct sha256_ctx *ctx);
+
+void
+sha256_update(struct sha256_ctx *ctx,
+	      unsigned length,
+	      const uint8_t *data);
+
+void
+sha256_final(struct sha256_ctx *ctx);
+
+void
+sha256_digest(const struct sha256_ctx *ctx,
+	      unsigned length,
+	      uint8_t *digest);
+
+
+#endif /* NETTLE_SHA_H_INCLUDED */
diff --git a/sha1.c b/sha1.c
index 8c044b71edf95c049a78a184f640115c29a2c780..a0982fb47da23fb978f0bb18982bad39be098d0b 100644
--- a/sha1.c
+++ b/sha1.c
@@ -35,7 +35,7 @@
  * effort (for example the reengineering of a great many Capstone chips).
  */
 
-#include "sha1.h"
+#include "sha.h"
 
 #include "macros.h"