diff --git a/armsrc/desfire_crypto.c b/armsrc/desfire_crypto.c
index 6bfc19416..a99a9a547 100644
--- a/armsrc/desfire_crypto.c
+++ b/armsrc/desfire_crypto.c
@@ -119,55 +119,24 @@ void tdes_nxp_send(const void *in, void *out, size_t length, const void *key, un
     }
 }
 
-void aes128_nxp_receive(const void *in, void *out, size_t length, const void *key, unsigned char iv[8]) {
+void aes128_nxp_receive(const void *in, void *out, size_t length, const void *key, unsigned char iv[16]) {
     if (length % 8) return;
 
+    uint8_t *tin = (uint8_t *) in;
+    uint8_t *tout = (uint8_t *) out;
+
     mbedtls_aes_setkey_dec(&actx, key, 128);
-
-    uint8_t i;
-    unsigned char temp[8];
-    uint8_t *tin = (uint8_t *) in;
-    uint8_t *tout = (uint8_t *) out;
-
-    while (length > 0) {
-        memcpy(temp, tin, 8);
-
-        mbedtls_aes_crypt_ecb(&actx, MBEDTLS_AES_DECRYPT, tin, tout);
-
-        for (i = 0; i < 8; i++) {
-            tout[i] = (unsigned char)(tout[i] ^ iv[i]);
-        }
-
-        memcpy(iv, temp, 8);
-
-        tin  += 8;
-        tout += 8;
-        length -= 8;
-    }
+    mbedtls_aes_crypt_cbc(&actx, MBEDTLS_AES_DECRYPT, length, iv, tin, tout);
 }
 
-void aes128_nxp_send(const void *in, void *out, size_t length, const void *key, unsigned char iv[8]) {
+void aes128_nxp_send(const void *in, void *out, size_t length, const void *key, unsigned char iv[16]) {
     if (length % 8) return;
 
-    mbedtls_aes_setkey_enc(&actx, key, 128);
-
-    uint8_t i;
     uint8_t *tin = (uint8_t *) in;
     uint8_t *tout = (uint8_t *) out;
 
-    while (length > 0) {
-        for (i = 0; i < 8; i++) {
-            tin[i] = (unsigned char)(tin[i] ^ iv[i]);
-        }
-
-        mbedtls_aes_crypt_ecb(&actx, MBEDTLS_AES_ENCRYPT, tin, tout);
-
-        memcpy(iv, tout, 8);
-
-        tin  += 8;
-        tout += 8;
-        length -= 8;
-    }
+    mbedtls_aes_setkey_enc(&actx, key, 128);
+    mbedtls_aes_crypt_cbc(&actx, MBEDTLS_AES_ENCRYPT, length, iv, tin, tout);
 }
 
 void Desfire_des_key_new(const uint8_t value[8], desfirekey_t key) {
diff --git a/armsrc/mifareutil.c b/armsrc/mifareutil.c
index e6569d12a..795e3ad36 100644
--- a/armsrc/mifareutil.c
+++ b/armsrc/mifareutil.c
@@ -381,17 +381,17 @@ int mifare_ultra_auth(uint8_t *keybytes) {
 int mifare_ultra_aes_auth(uint8_t keyno, uint8_t *keybytes) {
 
     /// aes-128
-    uint8_t random_a[16] = {1, 1, 1, 1, 1, 1, 1, 1};
-    uint8_t random_b[16] = {0x00};
-    uint8_t enc_random_b[16] = {0x00};
-    uint8_t rnd_ab[32] = {0x00};
-    uint8_t IV[16] = {0x00};
-    uint8_t key[16] = {0x00};
+    uint8_t random_a[16] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
+    uint8_t random_b[16] = { 0 };
+    uint8_t enc_random_b[16] = { 0 };
+    uint8_t rnd_ab[32] = { 0 };
+    uint8_t IV[16] = { 0 };
+    uint8_t key[16] = { 0 };
     memcpy(key, keybytes, sizeof(key));
 
     uint16_t len = 0;
     uint8_t resp[19] = {0x00};
-    uint8_t respPar[5] = {0, 0, 0};
+    uint8_t respPar[5] = {0};
 
     // REQUEST AUTHENTICATION
     len = mifare_sendcmd_short(NULL, CRYPT_NONE, MIFARE_ULAES_AUTH_1, keyno, resp, respPar, NULL);
@@ -414,7 +414,7 @@ int mifare_ultra_aes_auth(uint8_t keyno, uint8_t *keybytes) {
         Dbprintf("enc_B:");
         Dbhexdump(16, enc_random_b, false);
 
-        Dbprintf("    B:");
+        Dbprintf("B:");
         Dbhexdump(16, random_b, false);
 
         Dbprintf("rnd_ab:");
@@ -430,12 +430,13 @@ int mifare_ultra_aes_auth(uint8_t keyno, uint8_t *keybytes) {
         return 0;
     }
 
-    uint8_t enc_resp[16] = { 0, 0, 0, 0, 0, 0, 0, 0 };
-    uint8_t resp_random_a[16] = { 0, 0, 0, 0, 0, 0, 0, 0 };
+    uint8_t enc_resp[16] = { 0 };
+    uint8_t resp_random_a[16] = { 0 };
     memcpy(enc_resp, resp + 1, 16);
 
     // decrypt    out, in, length, key, iv
     aes128_nxp_receive(enc_resp, resp_random_a, 16, key, enc_random_b);
+
     if (memcmp(resp_random_a, random_a, 16) != 0) {
         if (g_dbglevel >= DBG_ERROR) Dbprintf("failed authentication");
         return 0;
@@ -446,10 +447,10 @@ int mifare_ultra_aes_auth(uint8_t keyno, uint8_t *keybytes) {
         Dbprintf("e_AB:");
         Dbhexdump(32, rnd_ab, false);
 
-        Dbprintf("  a:");
+        Dbprintf("A:");
         Dbhexdump(16, random_a, false);
 
-        Dbprintf("  b:");
+        Dbprintf("B:");
         Dbhexdump(16, resp_random_a, false);
     }
     return 1;