--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rsa.c	Mon May 31 18:21:40 2004 +0000
@@ -0,0 +1,273 @@
+/* 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
+ */
+
+/* RSA Code by Tom St Denis */
+#include "mycrypt.h"
+
+#ifdef MRSA
+
+int rsa_signpad(const unsigned char *in,  unsigned long inlen,
+                      unsigned char *out, unsigned long *outlen)
+{
+   unsigned long x, y;
+
+   _ARGCHK(in     != NULL);
+   _ARGCHK(out    != NULL);
+   _ARGCHK(outlen != NULL);
+
+   if (*outlen < (3 * inlen)) {
+      return CRYPT_BUFFER_OVERFLOW;
+   }
+
+   /* check inlen */
+   if (inlen > MAX_RSA_SIZE/8) {
+      return CRYPT_PK_INVALID_SIZE;
+   }
+
+   for (y = x = 0; x < inlen; x++)
+       out[y++] = (unsigned char)0xFF;
+   for (x = 0; x < inlen; x++)
+       out[y++] = in[x];
+   for (x = 0; x < inlen; x++)
+       out[y++] = (unsigned char)0xFF;
+   *outlen = 3 * inlen;
+   return CRYPT_OK;
+}
+
+int rsa_pad(const unsigned char *in,  unsigned long inlen,
+                  unsigned char *out, unsigned long *outlen,
+                  int wprng, prng_state *prng)
+{
+   unsigned char buf[3*(MAX_RSA_SIZE/8)];
+   unsigned long x;
+   int err;
+
+   _ARGCHK(in     != NULL);
+   _ARGCHK(out    != NULL);
+   _ARGCHK(outlen != NULL);
+
+   /* is output big enough? */
+   if (*outlen < (3 * inlen)) {
+      return CRYPT_BUFFER_OVERFLOW;
+   }
+
+   /* get random padding required */
+   if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
+      return err;
+   }
+
+   /* check inlen */
+   if (inlen > (MAX_RSA_SIZE/8)) {
+      return CRYPT_PK_INVALID_SIZE;
+   }
+
+   if (prng_descriptor[wprng].read(buf, inlen*2-2, prng) != (inlen*2 - 2))  {
+       return CRYPT_ERROR_READPRNG;
+   }
+
+   /* pad it like a sandwhich
+    *
+    * Looks like 0xFF R1 M R2 0xFF
+    *
+    * Where R1/R2 are random and exactly equal to the length of M minus one byte.
+    */
+   for (x = 0; x < inlen-1; x++) {
+       out[x+1] = buf[x];
+   }
+
+   for (x = 0; x < inlen; x++) {
+       out[x+inlen] = in[x];
+   }
+
+   for (x = 0; x < inlen-1; x++) {
+       out[x+inlen+inlen] = buf[x+inlen-1];
+   }
+
+   /* last and first bytes are 0xFF */
+   out[0] = out[inlen+inlen+inlen-1] = (unsigned char)0xFF;
+
+   /* clear up and return */
+#ifdef CLEAN_STACK
+   zeromem(buf, sizeof(buf));
+#endif
+   *outlen = inlen*3;
+   return CRYPT_OK;
+}
+
+int rsa_signdepad(const unsigned char *in,  unsigned long inlen,
+                        unsigned char *out, unsigned long *outlen)
+{
+   unsigned long x;
+
+   _ARGCHK(in     != NULL);
+   _ARGCHK(out    != NULL);
+   _ARGCHK(outlen != NULL);
+
+   if (*outlen < inlen/3) {
+      return CRYPT_BUFFER_OVERFLOW;
+   }
+
+   /* check padding bytes */
+   for (x = 0; x < inlen/3; x++) {
+       if (in[x] != (unsigned char)0xFF || in[x+(inlen/3)+(inlen/3)] != (unsigned char)0xFF) {
+          return CRYPT_INVALID_PACKET;
+       }
+   }
+   for (x = 0; x < inlen/3; x++) {
+       out[x] = in[x+(inlen/3)];
+   }
+   *outlen = inlen/3;
+   return CRYPT_OK;
+}
+
+int rsa_depad(const unsigned char *in,  unsigned long inlen,
+                    unsigned char *out, unsigned long *outlen)
+{
+   unsigned long x;
+
+   _ARGCHK(in     != NULL);
+   _ARGCHK(out    != NULL);
+   _ARGCHK(outlen != NULL);
+
+   if (*outlen < inlen/3) {
+      return CRYPT_BUFFER_OVERFLOW;
+   }
+   for (x = 0; x < inlen/3; x++) {
+       out[x] = in[x+(inlen/3)];
+   }
+   *outlen = inlen/3;
+   return CRYPT_OK;
+}
+
+int rsa_export(unsigned char *out, unsigned long *outlen, int type, rsa_key *key)
+{
+   unsigned long y, z; 
+   int err;
+
+   _ARGCHK(out    != NULL);
+   _ARGCHK(outlen != NULL);
+   _ARGCHK(key    != NULL);
+   
+   /* can we store the static header?  */
+   if (*outlen < (PACKET_SIZE + 1)) {
+      return CRYPT_BUFFER_OVERFLOW;
+   }   
+
+   /* type valid? */
+   if (!(key->type == PK_PRIVATE || key->type == PK_PRIVATE_OPTIMIZED) &&
+        (type == PK_PRIVATE || type == PK_PRIVATE_OPTIMIZED)) {
+      return CRYPT_PK_INVALID_TYPE;
+   }
+
+   /* start at offset y=PACKET_SIZE */
+   y = PACKET_SIZE;
+
+   /* output key type */
+   out[y++] = type;
+
+   /* output modulus */
+   OUTPUT_BIGNUM(&key->N, out, y, z);
+
+   /* output public key */
+   OUTPUT_BIGNUM(&key->e, out, y, z);
+
+   if (type == PK_PRIVATE || type == PK_PRIVATE_OPTIMIZED) {
+      OUTPUT_BIGNUM(&key->d, out, y, z);
+   }
+
+   if (type == PK_PRIVATE_OPTIMIZED) {
+      OUTPUT_BIGNUM(&key->dQ, out, y, z);
+      OUTPUT_BIGNUM(&key->dP, out, y, z);
+      OUTPUT_BIGNUM(&key->pQ, out, y, z);
+      OUTPUT_BIGNUM(&key->qP, out, y, z);
+      OUTPUT_BIGNUM(&key->p, out, y, z);
+      OUTPUT_BIGNUM(&key->q, out, y, z);
+   }
+
+   /* store packet header */
+   packet_store_header(out, PACKET_SECT_RSA, PACKET_SUB_KEY);
+
+   /* copy to the user buffer */
+   *outlen = y;
+
+   /* clear stack and return */
+   return CRYPT_OK;
+}
+
+int rsa_import(const unsigned char *in, unsigned long inlen, rsa_key *key)
+{
+   unsigned long x, y;
+   int err;
+
+   _ARGCHK(in  != NULL);
+   _ARGCHK(key != NULL);
+
+   /* check length */
+   if (inlen < (1+PACKET_SIZE)) {
+      return CRYPT_INVALID_PACKET;
+   }
+
+   /* test packet header */
+   if ((err = packet_valid_header((unsigned char *)in, PACKET_SECT_RSA, PACKET_SUB_KEY)) != CRYPT_OK) {
+      return err;
+   }
+
+   /* init key */
+   if ((err = mp_init_multi(&key->e, &key->d, &key->N, &key->dQ, &key->dP, &key->qP,
+                     &key->pQ, &key->p, &key->q, NULL)) != MP_OKAY) {
+      return mpi_to_ltc_error(err);
+   }
+
+   /* get key type */
+   y = PACKET_SIZE;
+   key->type = (int)in[y++];
+
+   /* load the modulus  */
+   INPUT_BIGNUM(&key->N, in, x, y, inlen);
+
+   /* load public exponent */
+   INPUT_BIGNUM(&key->e, in, x, y, inlen);
+
+   /* get private exponent */
+   if (key->type == PK_PRIVATE || key->type == PK_PRIVATE_OPTIMIZED) {
+      INPUT_BIGNUM(&key->d, in, x, y, inlen);
+   }
+
+   /* get CRT private data if required */
+   if (key->type == PK_PRIVATE_OPTIMIZED) {
+      INPUT_BIGNUM(&key->dQ, in, x, y, inlen);
+      INPUT_BIGNUM(&key->dP, in, x, y, inlen);
+      INPUT_BIGNUM(&key->pQ, in, x, y, inlen);
+      INPUT_BIGNUM(&key->qP, in, x, y, inlen);
+      INPUT_BIGNUM(&key->p, in, x, y, inlen);
+      INPUT_BIGNUM(&key->q, in, x, y, inlen);
+   }
+
+   /* free up ram not required */
+   if (key->type != PK_PRIVATE_OPTIMIZED) {
+      mp_clear_multi(&key->dQ, &key->dP, &key->pQ, &key->qP, &key->p, &key->q, NULL);
+   }
+   if (key->type != PK_PRIVATE && key->type != PK_PRIVATE_OPTIMIZED) {
+      mp_clear(&key->d);
+   }
+
+   return CRYPT_OK;
+error:
+   mp_clear_multi(&key->d, &key->e, &key->N, &key->dQ, &key->dP,
+                  &key->pQ, &key->qP, &key->p, &key->q, NULL);
+   return err;
+}
+
+#include "rsa_sys.c"
+
+#endif /* RSA */
+
+