X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/ae3340a0fb04bf8f8b8c874e0859d7d0886e2db1..c8a0f5503172f25620670a9ba992d8c923b5df95:/common/polarssl/libpcrypto.c

diff --git a/common/polarssl/libpcrypto.c b/common/polarssl/libpcrypto.c
index 032c3a18..9be9fd26 100644
--- a/common/polarssl/libpcrypto.c
+++ b/common/polarssl/libpcrypto.c
@@ -10,7 +10,9 @@
 
 #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 +43,41 @@ 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);
+	
+	// padding:  ISO/IEC 9797-1 Message Authentication Codes (MACs) - Part 1: Mechanisms using a block cipher
+	uint8_t data[2049] = {0}; // length + 16
+	memcpy(data, input, length);
+	data[length] = 0x80;
+	int datalen = (length & 0xfffffff0) + 0x10;
+	
+	//  NIST 800-38B 
+	aes_cmac128_context ctx;
+	aes_cmac128_starts(&ctx, key);
+	aes_cmac128_update(&ctx, data, datalen);
+	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;
+}