--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rsa_v15_decrypt_key.c	Sun Dec 19 11:34:45 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"
+
+#ifdef MRSA
+
+/* decrypt then PKCS #1 v1.5 depad  */
+int rsa_v15_decrypt_key(const unsigned char *in,     unsigned long  inlen,
+                              unsigned char *outkey, unsigned long keylen, 
+                              prng_state    *prng,   int            prng_idx,
+                              int           *res,    rsa_key       *key)
+{
+  unsigned long modulus_bitlen, modulus_bytelen, x;
+  int           err;
+  unsigned char *tmp;
+  
+  _ARGCHK(outkey != NULL);
+  _ARGCHK(key    != NULL);
+  _ARGCHK(res    != NULL);
+ 
+  /* default to invalid */
+  *res = 0;
+
+  /* valid prng ? */
+  if ((err = prng_is_valid(prng_idx)) != CRYPT_OK) {
+     return err;
+  }
+  
+  /* get modulus len in bits */
+  modulus_bitlen = mp_count_bits(&(key->N));
+
+  /* outlen must be at least the size of the modulus */
+  modulus_bytelen = mp_unsigned_bin_size(&(key->N));
+  if (modulus_bytelen != inlen) {
+     return CRYPT_INVALID_PACKET;
+  }
+
+  /* allocate ram */
+  tmp = XMALLOC(inlen);
+  if (tmp == NULL) {
+     return CRYPT_MEM;
+  }
+
+  /* rsa decode the packet */
+  x = inlen;
+  if ((err = rsa_exptmod(in, inlen, tmp, &x, PK_PRIVATE, prng, prng_idx, key)) != CRYPT_OK) {
+     XFREE(tmp);
+     return err;
+  }
+
+  /* PKCS #1 v1.5 depad */
+  err = pkcs_1_v15_es_decode(tmp, x, modulus_bitlen, outkey, keylen, res);
+  XFREE(tmp);
+  return err;
+}
+
+#endif