--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pkcs_1_v15_es_encode.c	Tue Jun 15 14:07:21 2004 +0000
@@ -0,0 +1,55 @@
+/* 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"
+
+/* v1.5 Encryption Padding for PKCS #1 -- Tom St Denis */
+
+#ifdef PKCS_1
+
+int pkcs_1_v15_es_encode(const unsigned char *msg,    unsigned long msglen,
+                               unsigned long  modulus_bitlen, 
+                               prng_state    *prng,   int           prng_idx,
+                               unsigned char *out,    unsigned long *outlen)
+{ 
+   unsigned long modulus_bytelen, x, y;
+
+   _ARGCHK(msg    != NULL);
+   _ARGCHK(out    != NULL);
+   _ARGCHK(outlen != NULL);
+
+   /* get modulus len */
+   modulus_bytelen = (modulus_bitlen >> 3) + (modulus_bitlen & 7 ? 1 : 0);
+   if (modulus_bytelen < 12) {
+      return CRYPT_INVALID_ARG;
+   }
+
+   /* verify length */
+   if (msglen > (modulus_bytelen - 11) || *outlen < modulus_bytelen) {
+      return CRYPT_PK_INVALID_SIZE;
+   }
+
+   /* 0x00 0x02 PS 0x00 M */
+   x = 0;
+   out[x++] = 0x00;
+   out[x++] = 0x02;
+   y = modulus_bytelen - msglen - 3;
+   if (prng_descriptor[prng_idx].read(out+x, y, prng) != y) {
+      return CRYPT_ERROR_READPRNG;
+   }
+   x += y;
+   out[x++] = 0x00;
+   memcpy(out+x, msg, msglen);
+   *outlen = modulus_bytelen;
+
+   return CRYPT_OK;
+}
+
+#endif /* PKCS_1 */