--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rsa_decrypt_key.c	Tue Jun 15 14:07:21 2004 +0000
@@ -0,0 +1,61 @@
+/* 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 OAEP depad  */
+int rsa_decrypt_key(const unsigned char *in,     unsigned long inlen,
+                          unsigned char *outkey, unsigned long *keylen, 
+                    const unsigned char *lparam, unsigned long lparamlen,
+                          prng_state    *prng,   int           prng_idx,
+                          int            hash_idx, int *res,
+                          rsa_key       *key)
+{
+  unsigned long modulus_bitlen, modulus_bytelen, x;
+  int           err;
+  
+  _ARGCHK(outkey != NULL);
+  _ARGCHK(keylen != NULL);
+  _ARGCHK(key    != NULL);
+  _ARGCHK(res    != NULL);
+  
+  /* valid hash ? */
+  if ((err = hash_is_valid(hash_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;
+  }
+
+  /* rsa decode the packet */
+  x = *keylen;
+  if ((err = rsa_exptmod(in, inlen, outkey, &x, PK_PRIVATE, prng, prng_idx, key)) != CRYPT_OK) {
+     return err;
+  }
+
+  /* now OAEP decode the packet */
+  return pkcs_1_oaep_decode(outkey, x, lparam, lparamlen, modulus_bitlen, hash_idx,
+                            outkey, keylen, res);
+}
+
+#endif /* MRSA */
+
+
+
+