1 files changed, 108 insertions, 0 deletions
diff --git a/libtomcrypt/src/encauth/eax/eax_decrypt_verify_memory.c b/libtomcrypt/src/encauth/eax/eax_decrypt_verify_memory.c
new file mode 100644
index 0000000..d6d72ab
--- /dev/null
+++ b/libtomcrypt/src/encauth/eax/eax_decrypt_verify_memory.c
@@ -0,0 +1,108 @@
+/* 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.org
+ */
+
+/**
+    @file eax_decrypt_verify_memory.c
+    EAX implementation, decrypt block of memory, by Tom St Denis
+*/
+#include "tomcrypt.h"
+
+#ifdef EAX_MODE
+
+/**
+   Decrypt a block of memory and verify the provided MAC tag with EAX
+   @param cipher     The index of the cipher desired
+   @param key        The secret key
+   @param keylen     The length of the key (octets)
+   @param nonce      The nonce data (use once) for the session
+   @param noncelen   The length of the nonce data.
+   @param header     The session header data
+   @param headerlen  The length of the header (octets)
+   @param ct         The ciphertext
+   @param ctlen      The length of the ciphertext (octets)
+   @param pt         [out] The plaintext
+   @param tag        The authentication tag provided by the encoder
+   @param taglen     [in/out] The length of the tag (octets)
+   @param stat       [out] The result of the decryption (1==valid tag, 0==invalid)
+   @return CRYPT_OK if successful regardless of the resulting tag comparison
+*/
+int eax_decrypt_verify_memory(int cipher,
+    const unsigned char *key,    unsigned long keylen,
+    const unsigned char *nonce,  unsigned long noncelen,
+    const unsigned char *header, unsigned long headerlen,
+    const unsigned char *ct,     unsigned long ctlen,
+          unsigned char *pt,
+          unsigned char *tag,    unsigned long taglen,
+          int           *stat)
+{
+   int            err;
+   eax_state     *eax;
+   unsigned char *buf;
+   unsigned long  buflen;
+
+   LTC_ARGCHK(stat != NULL);
+   LTC_ARGCHK(key  != NULL);
+   LTC_ARGCHK(pt   != NULL);
+   LTC_ARGCHK(ct   != NULL);
+   LTC_ARGCHK(tag  != NULL);
+
+   /* default to zero */
+   *stat = 0;
+
+   /* allocate ram */
+   buf = XMALLOC(taglen);
+   eax = XMALLOC(sizeof(*eax));
+   if (eax == NULL || buf == NULL) {
+      if (eax != NULL) {
+         XFREE(eax);
+      }
+      if (buf != NULL) {
+         XFREE(buf);
+      }
+      return CRYPT_MEM;
+   }
+
+   if ((err = eax_init(eax, cipher, key, keylen, nonce, noncelen, header, headerlen)) != CRYPT_OK) {
+      goto LBL_ERR;
+   }
+
+   if ((err = eax_decrypt(eax, ct, pt, ctlen)) != CRYPT_OK) {
+      goto LBL_ERR;
+   }
+ 
+   buflen = taglen;
+   if ((err = eax_done(eax, buf, &buflen)) != CRYPT_OK) {
+      goto LBL_ERR;
+   }
+
+   /* compare tags */
+   if (buflen >= taglen && memcmp(buf, tag, taglen) == 0) {
+      *stat = 1;
+   }
+   
+   err = CRYPT_OK;
+LBL_ERR:
+#ifdef LTC_CLEAN_STACK
+   zeromem(buf, taglen);
+   zeromem(eax, sizeof(*eax));
+#endif
+
+   XFREE(eax);
+   XFREE(buf);
+
+   return err;
+}
+
+#endif
+
+/* $Source: /cvs/libtom/libtomcrypt/src/encauth/eax/eax_decrypt_verify_memory.c,v $ */
+/* $Revision: 1.3 $ */
+/* $Date: 2005/05/05 14:35:58 $ */