--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/pk/rsa/rsa_import.c	Fri May 06 13:23:02 2005 +0000
@@ -0,0 +1,112 @@
+/* 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 "tomcrypt.h"
+
+/**
+  @file rsa_import.c
+  Import a PKCS RSA key, Tom St Denis
+*/  
+
+#ifdef MRSA
+
+/**
+  Import an RSAPublicKey or RSAPrivateKey [two-prime only, defined in PKCS #1 v2.1]
+  @param in      The packet to import from
+  @param inlen   It's length (octets)
+  @param key     [out] Destination for newly imported key
+  @return CRYPT_OK if successful, upon error allocated memory is freed
+*/
+int rsa_import(const unsigned char *in, unsigned long inlen, rsa_key *key)
+{
+   unsigned long x, y;
+   int err;
+
+   LTC_ARGCHK(in  != NULL);
+   LTC_ARGCHK(key != NULL);
+
+   /* init key */
+   if ((err = mp_init_multi(&key->e, &key->d, &key->N, &key->dQ, &key->dP, &key->qP,
+                     &key->p, &key->q, NULL)) != MP_OKAY) {
+      return mpi_to_ltc_error(err);
+   }
+
+   /* check the header */
+   if (inlen < 4) {
+      return CRYPT_INVALID_PACKET;
+   }
+
+   /* should be 0x30 0x8{1|2} LL LL */
+   if ((in[0] != 0x30) || ((in[1] != 0x81) && (in[1] != 0x82))) {
+      return CRYPT_INVALID_PACKET;
+   }
+
+   /* ok all the ASN.1 params are fine so far, let's move up */
+   x = ((unsigned long)in[2]);
+   y = 0;
+   if ((in[1] & ~0x80) == 2) {
+      x   = (x << 8) + ((unsigned long)in[3]) + 1;
+      in += 1;
+      y   = 1;
+   }
+   in += 3; /* advance input */
+   x  += 3; /* size of packet according to header */
+   y  += 3; /* used input */
+
+   if (x != inlen) {
+      return CRYPT_INVALID_PACKET;
+   }
+   
+   /* decrement inlen by the header size */
+   inlen -= y;
+
+   /* read first number, it's either N or 0 [0 == private key] */
+   x = inlen;
+   if ((err = der_get_multi_integer(in, &x, &key->N, NULL)) != CRYPT_OK) {
+      goto LBL_ERR;
+   }
+
+   /* advance */
+   inlen -= x;
+   in    += x;
+
+   if (mp_cmp_d(&key->N, 0) == MP_EQ) {
+      /* it's a private key */
+      if ((err = der_get_multi_integer(in, &inlen, &key->N, &key->e,
+                          &key->d, &key->p, &key->q, &key->dP,
+                          &key->dQ, &key->qP, NULL)) != CRYPT_OK) {
+         goto LBL_ERR;
+      }
+
+      key->type = PK_PRIVATE;
+   } else if (mp_cmp_d(&key->N, 1) == MP_EQ) {
+      /* we don't support multi-prime RSA */
+      err = CRYPT_PK_INVALID_TYPE;
+      goto LBL_ERR;
+   } else {
+      /* it's a public key and we lack e */
+      if ((err = der_get_multi_integer(in, &inlen, &key->e, NULL)) != CRYPT_OK) {
+         goto LBL_ERR;
+      }
+
+      /* free up some ram */
+      mp_clear_multi(&key->p, &key->q, &key->qP, &key->dP, &key->dQ, NULL);
+
+      key->type = PK_PUBLIC;
+   }
+   return CRYPT_OK;
+LBL_ERR:
+   mp_clear_multi(&key->d, &key->e, &key->N, &key->dQ, &key->dP,
+                  &key->qP, &key->p, &key->q, NULL);
+   return err;
+}
+
+#endif /* MRSA */
+