--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rsa_sys.c	Mon May 31 18:25:41 2004 +0000
@@ -0,0 +1,274 @@
+/* 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
+ */
+
+/* these are smaller routines written by Clay Culver.  They do the same function as the rsa_encrypt/decrypt 
+ * except that they are used to RSA encrypt/decrypt a single value and not a packet.
+ */
+int rsa_encrypt_key(const unsigned char *inkey, unsigned long inlen,
+                    unsigned char *outkey, unsigned long *outlen,
+                    prng_state *prng, int wprng, rsa_key *key)
+{
+   unsigned char rsa_in[RSA_STACK], rsa_out[RSA_STACK];
+   unsigned long x, y, rsa_size;
+   int err;
+
+   _ARGCHK(inkey  != NULL);
+   _ARGCHK(outkey != NULL);
+   _ARGCHK(outlen != NULL);
+   _ARGCHK(key    != NULL);
+   
+   /* only allow keys from 64 to 256 bits */
+   if (inlen < 8 || inlen > 32) {
+      return CRYPT_INVALID_ARG;
+   }
+
+   /* are the parameters valid? */
+   if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
+      return err; 
+   }
+
+   /* rsa_pad the symmetric key */
+   y = (unsigned long)sizeof(rsa_in); 
+   if ((err = rsa_pad(inkey, inlen, rsa_in, &y, wprng, prng)) != CRYPT_OK) {
+      return CRYPT_ERROR;
+   }
+   
+   /* rsa encrypt it */
+   rsa_size = (unsigned long)sizeof(rsa_out);
+   if ((err = rsa_exptmod(rsa_in, y, rsa_out, &rsa_size, PK_PUBLIC, key)) != CRYPT_OK) {
+      return CRYPT_ERROR;
+   }
+
+   /* check size */
+   if (*outlen < (PACKET_SIZE+4+rsa_size)) { 
+      return CRYPT_BUFFER_OVERFLOW;
+   }
+
+   /* store header */
+   packet_store_header(outkey, PACKET_SECT_RSA, PACKET_SUB_ENC_KEY);
+
+   /* now lets make the header */
+   y = PACKET_SIZE;
+   
+   /* store the size of the RSA value */
+   STORE32L(rsa_size, (outkey+y));
+   y += 4;
+
+   /* store the rsa value */
+   for (x = 0; x < rsa_size; x++, y++) {
+       outkey[y] = rsa_out[x];
+   }
+
+   *outlen = y;
+#ifdef CLEAN_STACK
+   /* clean up */
+   zeromem(rsa_in, sizeof(rsa_in));
+   zeromem(rsa_out, sizeof(rsa_out));
+#endif
+
+   return CRYPT_OK;
+}
+
+int rsa_decrypt_key(const unsigned char *in, unsigned long inlen,
+                          unsigned char *outkey, unsigned long *keylen, 
+                          rsa_key *key)
+{
+   unsigned char sym_key[MAXBLOCKSIZE], rsa_out[RSA_STACK];
+   unsigned long x, y, z, i, rsa_size;
+   int err;
+
+   _ARGCHK(in     != NULL);
+   _ARGCHK(outkey != NULL);
+   _ARGCHK(keylen != NULL);
+   _ARGCHK(key    != NULL);
+
+   /* right key type? */
+   if (key->type != PK_PRIVATE && key->type != PK_PRIVATE_OPTIMIZED) {
+      return CRYPT_PK_NOT_PRIVATE;
+   }
+
+   if (inlen < PACKET_SIZE+4) {
+      return CRYPT_INVALID_PACKET;
+   } else {
+      inlen -= PACKET_SIZE+4;
+   }
+
+   /* check the header */
+   if ((err = packet_valid_header((unsigned char *)in, PACKET_SECT_RSA, PACKET_SUB_ENC_KEY)) != CRYPT_OK) {
+      return err;
+   }
+
+   /* grab length of the rsa key */
+   y = PACKET_SIZE;
+   LOAD32L(rsa_size, (in+y));
+   if (inlen < rsa_size) {
+      return CRYPT_INVALID_PACKET;
+   } else {
+      inlen -= rsa_size;
+   }
+   y += 4;
+
+   /* decrypt it */
+   x = (unsigned long)sizeof(rsa_out);
+   if ((err = rsa_exptmod(in+y, rsa_size, rsa_out, &x, PK_PRIVATE, key)) != CRYPT_OK) {
+      return err;
+   }
+   y += rsa_size;
+
+   /* depad it */
+   z = (unsigned long)sizeof(sym_key);
+   if ((err = rsa_depad(rsa_out, x, sym_key, &z)) != CRYPT_OK) {
+      return err;
+   }
+
+   /* check size */
+   if (*keylen < z) { 
+      return CRYPT_BUFFER_OVERFLOW;
+   }
+
+   for (i = 0; i < z; i++) {
+     outkey[i] = sym_key[i];
+   }
+   
+#ifdef CLEAN_STACK
+   /* clean up */
+   zeromem(sym_key, sizeof(sym_key));
+   zeromem(rsa_out, sizeof(rsa_out));
+#endif
+   *keylen = z;
+   return CRYPT_OK;
+}
+
+int rsa_sign_hash(const unsigned char *in,  unsigned long inlen, 
+                        unsigned char *out, unsigned long *outlen, 
+                        rsa_key *key)
+{
+   unsigned long rsa_size, x, y;
+   unsigned char rsa_in[RSA_STACK], rsa_out[RSA_STACK];
+   int err;
+
+   _ARGCHK(in     != NULL);
+   _ARGCHK(out    != NULL);
+   _ARGCHK(outlen != NULL);
+   _ARGCHK(key    != NULL);
+   
+   /* reject nonsense sizes */
+   if (inlen > (512/3) || inlen < 16) {
+      return CRYPT_INVALID_ARG;
+   }
+
+   /* type of key? */
+   if (key->type != PK_PRIVATE && key->type != PK_PRIVATE_OPTIMIZED) {
+      return CRYPT_PK_NOT_PRIVATE;
+   }
+
+   /* pad it */
+   x = (unsigned long)sizeof(rsa_out);
+   if ((err = rsa_signpad(in, inlen, rsa_out, &x)) != CRYPT_OK) {
+      return err;
+   }
+
+   /* sign it */
+   rsa_size = (unsigned long)sizeof(rsa_in);
+   if ((err = rsa_exptmod(rsa_out, x, rsa_in, &rsa_size, PK_PRIVATE, key)) != CRYPT_OK) {
+      return err;
+   }
+
+   /* check size */
+   if (*outlen < (PACKET_SIZE+4+rsa_size)) {
+      return CRYPT_BUFFER_OVERFLOW;
+   }
+
+   /* now lets output the message */
+   y = PACKET_SIZE;
+
+   /* output the len */
+   STORE32L(rsa_size, (out+y));
+   y += 4;
+
+   /* store the signature */
+   for (x = 0; x < rsa_size; x++, y++) {
+       out[y] = rsa_in[x];
+   }
+
+   /* store header */
+   packet_store_header(out, PACKET_SECT_RSA, PACKET_SUB_SIGNED);
+
+#ifdef CLEAN_STACK
+   /* clean up */
+   zeromem(rsa_in, sizeof(rsa_in));
+   zeromem(rsa_out, sizeof(rsa_out));
+#endif
+   *outlen = y;
+   return CRYPT_OK;
+}
+
+int rsa_verify_hash(const unsigned char *sig, unsigned long siglen,
+                    const unsigned char *md, int *stat, rsa_key *key)
+{
+   unsigned long rsa_size, x, y, z;
+   unsigned char rsa_in[RSA_STACK], rsa_out[RSA_STACK];
+   int err;
+
+   _ARGCHK(sig  != NULL);
+   _ARGCHK(md   != NULL);
+   _ARGCHK(stat != NULL);
+   _ARGCHK(key  != NULL);
+
+   /* always be incorrect by default */
+   *stat = 0;
+   
+   if (siglen < PACKET_SIZE+4) {
+      return CRYPT_INVALID_PACKET;
+   } else {
+      siglen -= PACKET_SIZE+4;
+   }
+
+   /* verify header */
+   if ((err = packet_valid_header((unsigned char *)sig, PACKET_SECT_RSA, PACKET_SUB_SIGNED)) != CRYPT_OK) {
+      return err;
+   }
+
+   /* get the len */
+   y = PACKET_SIZE;
+   LOAD32L(rsa_size, (sig+y));
+   if (siglen < rsa_size) {
+      return CRYPT_INVALID_PACKET;
+   } else {
+      siglen -= rsa_size;
+   }
+   y += 4;
+
+   /* exptmod it */
+   x = (unsigned long)sizeof(rsa_out);
+   if ((err = rsa_exptmod(sig+y, rsa_size, rsa_out, &x, PK_PUBLIC, key)) != CRYPT_OK) {
+      return err;
+   }
+   y += rsa_size;
+
+   /* depad it */
+   z = (unsigned long)sizeof(rsa_in);
+   if ((err = rsa_signdepad(rsa_out, x, rsa_in, &z)) != CRYPT_OK) {
+      return err;
+   }
+
+   /* check? */
+   if (memcmp(rsa_in, md, (size_t)z) == 0) {
+      *stat = 1;
+   }
+
+#ifdef CLEAN_STACK
+   zeromem(rsa_in, sizeof(rsa_in));
+   zeromem(rsa_out, sizeof(rsa_out));
+#endif
+   return CRYPT_OK;
+}
+