version 0.3.33

[fms.git] / libs / libtomcrypt / pk / rsa / rsa_decrypt_key.c

diff --git a/libs/libtomcrypt/pk/rsa/rsa_decrypt_key.c b/libs/libtomcrypt/pk/rsa/rsa_decrypt_key.c
new file mode 100644 (file)
index 0000000..3dce20f
--- /dev/null
+++ b/libs/libtomcrypt/pk/rsa/rsa_decrypt_key.c
@@ -0,0 +1,105 @@
+/* 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, tomstdenis@gmail.com, http://libtomcrypt.com
+ */
+#include "tomcrypt.h"
+
+/**
+  @file rsa_decrypt_key.c
+  RSA PKCS #1 Decryption, Tom St Denis and Andreas Lange
+*/
+
+#ifdef MRSA
+
+/**
+   PKCS #1 decrypt then v1.5 or OAEP depad
+   @param in          The ciphertext
+   @param inlen       The length of the ciphertext (octets)
+   @param out         [out] The plaintext
+   @param outlen      [in/out] The max size and resulting size of the plaintext (octets)
+   @param lparam      The system "lparam" value
+   @param lparamlen   The length of the lparam value (octets)
+   @param hash_idx    The index of the hash desired
+   @param padding     Type of padding (LTC_PKCS_1_OAEP or LTC_PKCS_1_V1_5)
+   @param stat        [out] Result of the decryption, 1==valid, 0==invalid
+   @param key         The corresponding private RSA key
+   @return CRYPT_OK if succcessul (even if invalid)
+*/
+int rsa_decrypt_key_ex(const unsigned char *in,       unsigned long  inlen,
+                             unsigned char *out,      unsigned long *outlen,
+                       const unsigned char *lparam,   unsigned long  lparamlen,
+                             int            hash_idx, int            padding,
+                             int           *stat,     rsa_key       *key)
+{
+  unsigned long modulus_bitlen, modulus_bytelen, x;
+  int           err;
+  unsigned char *tmp;
+
+  LTC_ARGCHK(out    != NULL);
+  LTC_ARGCHK(outlen != NULL);
+  LTC_ARGCHK(key    != NULL);
+  LTC_ARGCHK(stat   != NULL);
+
+  /* default to invalid */
+  *stat = 0;
+
+  /* valid padding? */
+
+  if ((padding != LTC_PKCS_1_V1_5) &&
+      (padding != LTC_PKCS_1_OAEP)) {
+    return CRYPT_PK_INVALID_PADDING;
+  }
+
+  if (padding == LTC_PKCS_1_OAEP) {
+    /* 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;
+  }
+
+  /* allocate ram */
+  tmp = XMALLOC(inlen);
+  if (tmp == NULL) {
+     return CRYPT_MEM;
+  }
+
+  /* rsa decode the packet */
+  x = inlen;
+  if ((err = ltc_mp.rsa_me(in, inlen, tmp, &x, PK_PRIVATE, key)) != CRYPT_OK) {
+     XFREE(tmp);
+     return err;
+  }
+
+  if (padding == LTC_PKCS_1_OAEP) {
+    /* now OAEP decode the packet */
+    err = pkcs_1_oaep_decode(tmp, x, lparam, lparamlen, modulus_bitlen, hash_idx,
+                             out, outlen, stat);
+  } else {
+    /* now PKCS #1 v1.5 depad the packet */
+    err = pkcs_1_v1_5_decode(tmp, x, LTC_PKCS_1_EME, modulus_bitlen, out, outlen, stat);
+  }
+
+  XFREE(tmp);
+  return err;
+}
+
+#endif /* MRSA */
+
+/* $Source: /cvs/libtom/libtomcrypt/src/pk/rsa/rsa_decrypt_key.c,v $ */
+/* $Revision: 1.8 $ */
+/* $Date: 2006/11/01 09:18:22 $ */