--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pkcs_1_mgf1.c	Mon May 31 18:25:41 2004 +0000
@@ -0,0 +1,66 @@
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis
+ *
+ * LibTomCrypt is a library that provides various cryptographic
+ * algorithms in a highly modular and flexible manner.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, [email protected], http://libtomcrypt.org
+ */
+#include "mycrypt.h"
+
+/* The Mask Generation Function (MGF1) for PKCS #1 -- Tom St Denis */
+
+#ifdef PKCS_1
+
+int pkcs_1_mgf1(const unsigned char *seed, unsigned long seedlen,
+                      int            hash_idx,
+                      unsigned char *mask, unsigned long masklen)
+{
+   unsigned long hLen, counter, x;
+   int           err;
+   hash_state    md;
+   unsigned char buf[MAXBLOCKSIZE];
+ 
+   _ARGCHK(seed != NULL);
+   _ARGCHK(mask != NULL);
+
+   /* ensure valid hash */
+   if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) { 
+      return err;
+   }
+
+   /* get hash output size */
+   hLen = hash_descriptor[hash_idx].hashsize;
+
+   /* start counter */
+   counter = 0;
+
+   while (masklen > 0) {
+       /* handle counter */
+       STORE32H(counter, buf);
+       ++counter;
+
+       /* get hash of seed || counter */
+       hash_descriptor[hash_idx].init(&md);
+       if ((err = hash_descriptor[hash_idx].process(&md, seed, seedlen)) != CRYPT_OK) {
+          return err;
+       }
+       if ((err = hash_descriptor[hash_idx].process(&md, buf, 4)) != CRYPT_OK) {
+          return err;
+       }
+       if ((err = hash_descriptor[hash_idx].done(&md, buf)) != CRYPT_OK) {
+          return err;
+       }
+
+       /* store it */
+       for (x = 0; x < hLen && masklen > 0; x++, masklen--) {
+          *mask++ = buf[x];
+       }
+   }
+
+   return CRYPT_OK;
+}
+
+#endif /* PKCS_1 */