X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/ae3340a0fb04bf8f8b8c874e0859d7d0886e2db1..4b5d696c179edc687ba0b61c7d96ea0ef54cad44:/common/polarssl/libpcrypto.c

diff --git a/common/polarssl/libpcrypto.c b/common/polarssl/libpcrypto.c
index 032c3a18..13e37f00 100644
--- a/common/polarssl/libpcrypto.c
+++ b/common/polarssl/libpcrypto.c
@@ -1,5 +1,6 @@
 //-----------------------------------------------------------------------------
 // Copyright (C) 2018 Merlok
+// Copyright (C) 2018 drHatson
 //
 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
 // at your option, any later version. See the LICENSE.txt file for the text of
@@ -10,7 +11,9 @@
 
 #include "polarssl/libpcrypto.h"
 #include <polarssl/aes.h>
+#include <polarssl/aes_cmac128.h>
 
+// NIST Special Publication 800-38A — Recommendation for block cipher modes of operation: methods and techniques, 2001.
 int aes_encode(uint8_t *iv, uint8_t *key, uint8_t *input, uint8_t *output, int length){
 	uint8_t iiv[16] = {0};
 	if (iv)
@@ -41,4 +44,35 @@ int aes_decode(uint8_t *iv, uint8_t *key, uint8_t *input, uint8_t *output, int l
 	aes_free(&aes);
 
 	return 0;
-}
\ No newline at end of file
+}
+
+// NIST Special Publication 800-38B — Recommendation for block cipher modes of operation: The CMAC mode for authentication.
+// https://csrc.nist.gov/CSRC/media/Projects/Cryptographic-Standards-and-Guidelines/documents/examples/AES_CMAC.pdf
+int aes_cmac(uint8_t *iv, uint8_t *key, uint8_t *input, uint8_t *mac, int length) {
+	memset(mac, 0x00, 16);
+	uint8_t iiv[16] = {0};
+	if (iv)
+		memcpy(iiv, iv, 16);
+	
+	//  NIST 800-38B 
+	aes_cmac128_context ctx;
+	aes_cmac128_starts(&ctx, key);
+	aes_cmac128_update(&ctx, input, length);
+	aes_cmac128_final(&ctx, mac);
+
+	return 0;
+}
+
+int aes_cmac8(uint8_t *iv, uint8_t *key, uint8_t *input, uint8_t *mac, int length) {
+	uint8_t cmac[16] = {0};
+	memset(mac, 0x00, 8);
+	
+	int res = aes_cmac(iv, key, input, cmac, length);
+	if (res)
+		return res;
+	
+	for(int i = 0; i < 8; i++) 
+		mac[i] = cmac[i * 2 + 1];
+
+	return 0;
+}