--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/mac/hmac/hmac_done.c	Fri May 06 13:23:02 2005 +0000
@@ -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, [email protected], http://libtomcrypt.org
+ */
+#include "tomcrypt.h"
+
+/**
+  @file hmac_done.c
+  HMAC support, terminate stream, Tom St Denis/Dobes Vandermeer
+*/
+
+#ifdef HMAC
+
+#define HMAC_BLOCKSIZE hash_descriptor[hash].blocksize
+
+/**
+   Terminate an HMAC session
+   @param hmac    The HMAC state
+   @param out     [out] The destination of the HMAC authentication tag
+   @param outlen  [in/out]  The max size and resulting size of the HMAC authentication tag
+   @return CRYPT_OK if successful
+*/
+int hmac_done(hmac_state *hmac, unsigned char *out, unsigned long *outlen)
+{
+    unsigned char *buf, *isha;
+    unsigned long hashsize, i;
+    int hash, err;
+
+    LTC_ARGCHK(hmac  != NULL);
+    LTC_ARGCHK(out   != NULL);
+
+    /* test hash */
+    hash = hmac->hash;
+    if((err = hash_is_valid(hash)) != CRYPT_OK) {
+        return err;
+    }
+
+    /* get the hash message digest size */
+    hashsize = hash_descriptor[hash].hashsize;
+
+    /* allocate buffers */
+    buf  = XMALLOC(HMAC_BLOCKSIZE);
+    isha = XMALLOC(hashsize);
+    if (buf == NULL || isha == NULL) { 
+       if (buf != NULL) {
+          XFREE(buf);
+       } 
+       if (isha != NULL) {
+          XFREE(isha);
+       }  
+       return CRYPT_MEM;
+    }
+
+    /* Get the hash of the first HMAC vector plus the data */
+    if ((err = hash_descriptor[hash].done(&hmac->md, isha)) != CRYPT_OK) {
+       goto LBL_ERR;
+    }
+
+    /* Create the second HMAC vector vector for step (3) */
+    for(i=0; i < HMAC_BLOCKSIZE; i++) {
+        buf[i] = hmac->key[i] ^ 0x5C;
+    }
+
+    /* Now calculate the "outer" hash for step (5), (6), and (7) */
+    if ((err = hash_descriptor[hash].init(&hmac->md)) != CRYPT_OK) {
+       goto LBL_ERR;
+    }
+    if ((err = hash_descriptor[hash].process(&hmac->md, buf, HMAC_BLOCKSIZE)) != CRYPT_OK) {
+       goto LBL_ERR;
+    }
+    if ((err = hash_descriptor[hash].process(&hmac->md, isha, hashsize)) != CRYPT_OK) {
+       goto LBL_ERR;
+    }
+    if ((err = hash_descriptor[hash].done(&hmac->md, buf)) != CRYPT_OK) {
+       goto LBL_ERR;
+    }
+
+    /* copy to output  */
+    for (i = 0; i < hashsize && i < *outlen; i++) {
+        out[i] = buf[i];
+    }
+    *outlen = i;
+
+    err = CRYPT_OK;
+LBL_ERR:
+    XFREE(hmac->key);
+#ifdef LTC_CLEAN_STACK
+    zeromem(isha, hashsize);
+    zeromem(buf,  hashsize);
+    zeromem(hmac, sizeof(*hmac));
+#endif
+
+    XFREE(isha);
+    XFREE(buf);
+
+    return err;
+}
+
+#endif