diff --git a/crypto/hmac.c b/crypto/hmac.c
new file mode 100644
index 0000000..847df92
--- /dev/null
+++ b/crypto/hmac.c
@@ -0,0 +1,134 @@
+/*
+ * Cryptographic API.
+ *
+ * HMAC: Keyed-Hashing for Message Authentication (RFC2104).
+ *
+ * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ *
+ * The HMAC implementation is derived from USAGI.
+ * Copyright (c) 2002 Kazunori Miyazawa <miyazawa@linux-ipv6.org> / USAGI
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option) 
+ * any later version.
+ *
+ */
+#include <linux/crypto.h>
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <linux/slab.h>
+#include <asm/scatterlist.h>
+#include "internal.h"
+
+static void hash_key(struct crypto_tfm *tfm, u8 *key, unsigned int keylen)
+{
+	struct scatterlist tmp;
+	
+	tmp.page = virt_to_page(key);
+	tmp.offset = offset_in_page(key);
+	tmp.length = keylen;
+	crypto_digest_digest(tfm, &tmp, 1, key);
+		
+}
+
+int crypto_alloc_hmac_block(struct crypto_tfm *tfm)
+{
+	int ret = 0;
+
+	BUG_ON(!crypto_tfm_alg_blocksize(tfm));
+	
+	tfm->crt_digest.dit_hmac_block = kmalloc(crypto_tfm_alg_blocksize(tfm),
+	                                         GFP_KERNEL);
+	if (tfm->crt_digest.dit_hmac_block == NULL)
+		ret = -ENOMEM;
+
+	return ret;
+		
+}
+
+void crypto_free_hmac_block(struct crypto_tfm *tfm)
+{
+	if (tfm->crt_digest.dit_hmac_block)
+		kfree(tfm->crt_digest.dit_hmac_block);
+}
+
+void crypto_hmac_init(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen)
+{
+	unsigned int i;
+	struct scatterlist tmp;
+	char *ipad = tfm->crt_digest.dit_hmac_block;
+	
+	if (*keylen > crypto_tfm_alg_blocksize(tfm)) {
+		hash_key(tfm, key, *keylen);
+		*keylen = crypto_tfm_alg_digestsize(tfm);
+	}
+
+	memset(ipad, 0, crypto_tfm_alg_blocksize(tfm));
+	memcpy(ipad, key, *keylen);
+
+	for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++)
+		ipad[i] ^= 0x36;
+
+	tmp.page = virt_to_page(ipad);
+	tmp.offset = offset_in_page(ipad);
+	tmp.length = crypto_tfm_alg_blocksize(tfm);
+	
+	crypto_digest_init(tfm);
+	crypto_digest_update(tfm, &tmp, 1);
+}
+
+void crypto_hmac_update(struct crypto_tfm *tfm,
+                        struct scatterlist *sg, unsigned int nsg)
+{
+	crypto_digest_update(tfm, sg, nsg);
+}
+
+void crypto_hmac_final(struct crypto_tfm *tfm, u8 *key,
+                       unsigned int *keylen, u8 *out)
+{
+	unsigned int i;
+	struct scatterlist tmp;
+	char *opad = tfm->crt_digest.dit_hmac_block;
+	
+	if (*keylen > crypto_tfm_alg_blocksize(tfm)) {
+		hash_key(tfm, key, *keylen);
+		*keylen = crypto_tfm_alg_digestsize(tfm);
+	}
+
+	crypto_digest_final(tfm, out);
+
+	memset(opad, 0, crypto_tfm_alg_blocksize(tfm));
+	memcpy(opad, key, *keylen);
+		
+	for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++)
+		opad[i] ^= 0x5c;
+
+	tmp.page = virt_to_page(opad);
+	tmp.offset = offset_in_page(opad);
+	tmp.length = crypto_tfm_alg_blocksize(tfm);
+
+	crypto_digest_init(tfm);
+	crypto_digest_update(tfm, &tmp, 1);
+	
+	tmp.page = virt_to_page(out);
+	tmp.offset = offset_in_page(out);
+	tmp.length = crypto_tfm_alg_digestsize(tfm);
+	
+	crypto_digest_update(tfm, &tmp, 1);
+	crypto_digest_final(tfm, out);
+}
+
+void crypto_hmac(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen,
+                 struct scatterlist *sg, unsigned int nsg, u8 *out)
+{
+	crypto_hmac_init(tfm, key, keylen);
+	crypto_hmac_update(tfm, sg, nsg);
+	crypto_hmac_final(tfm, key, keylen, out);
+}
+
+EXPORT_SYMBOL_GPL(crypto_hmac_init);
+EXPORT_SYMBOL_GPL(crypto_hmac_update);
+EXPORT_SYMBOL_GPL(crypto_hmac_final);
+EXPORT_SYMBOL_GPL(crypto_hmac);
+