Mfp read plain (#704)

[proxmark3-svn] / common / polarssl / libpcrypto.c

diff --git a/common/polarssl/libpcrypto.c b/common/polarssl/libpcrypto.c
index 032c3a18bcf49bb6fda4b996b329de4692ea568c..9be9fd266e32105a6ce0bbc8021dad37eff03610 100644 (file)
--- 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 \97 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 \97 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;
+}