--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pkcs_5_2.c	Mon May 31 18:21:40 2004 +0000
@@ -0,0 +1,88 @@
+/* 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>
+
+/* PKCS #5, Algorithm #2 */
+#ifdef PKCS_5
+
+int pkcs_5_alg2(const unsigned char *password, unsigned long password_len, 
+                const unsigned char *salt,     unsigned long salt_len,
+                int iteration_count,           int hash_idx,
+                unsigned char *out,            unsigned long *outlen)
+{
+   int err, itts;
+   unsigned long stored, left, x, y, blkno;
+   unsigned char buf[2][MAXBLOCKSIZE];
+   hmac_state    hmac;
+
+   _ARGCHK(password != NULL);
+   _ARGCHK(salt     != NULL);
+   _ARGCHK(out      != NULL);
+   _ARGCHK(outlen   != NULL);
+
+   /* test hash IDX */
+   if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) {
+      return err;
+   }
+
+   left   = *outlen;
+   blkno  = 1;
+   stored = 0;
+   while (left != 0) {
+       /* process block number blkno */
+       zeromem(buf, sizeof(buf));
+       
+       /* store current block number and increment for next pass */
+       STORE32H(blkno, buf[1]);
+       ++blkno;
+
+       /* get PRF(P, S||int(blkno)) */
+       if ((err = hmac_init(&hmac, hash_idx, password, password_len)) != CRYPT_OK) { 
+          return err; 
+       }
+       if ((err = hmac_process(&hmac, salt, salt_len)) != CRYPT_OK) {
+          return err;
+       }
+       if ((err = hmac_process(&hmac, buf[1], 4)) != CRYPT_OK) {
+          return err;
+       }
+       x = sizeof(buf[0]);
+       if ((err = hmac_done(&hmac, buf[0], &x)) != CRYPT_OK) {
+          return err;
+       }
+
+       /* now compute repeated and XOR it in buf[1] */
+       memcpy(buf[1], buf[0], x);
+       for (itts = 2; itts < iteration_count; ++itts) {
+           if ((err = hmac_memory(hash_idx, password, password_len, buf[0], x, buf[0], &x)) != CRYPT_OK) {
+              return err;
+           }
+           for (y = 0; y < x; y++) {
+               buf[1][y] ^= buf[0][y];
+           }
+       }
+
+       /* now emit upto x bytes of buf[1] to output */
+       for (y = 0; y < x && left != 0; ++y) {
+           out[stored++] = buf[1][y];
+           --left;
+       }
+   }
+   *outlen = stored;
+
+#ifdef CLEAN_STACK
+   zeromem(buf, sizeof(buf));
+#endif
+   return CRYPT_OK;
+}
+
+#endif
+