diff --git a/armsrc/des.c b/armsrc/des.c
index ccd32be7d..af10423f3 100644
--- a/armsrc/des.c
+++ b/armsrc/des.c
@@ -388,30 +388,6 @@ void tdes_dec(void *out, void *in, const uint8_t *key) {
     des_dec(out, out, (uint8_t *)key + 0);
 }
 
-void tdes_2key_enc(void *out, const void *in, size_t length, const void *key, unsigned char iv[8]) {
-
-    if (length % 8) return;
-
-    uint8_t i;
-    uint8_t *tin = (uint8_t *) in;
-    uint8_t *tout = (uint8_t *) out;
-
-    while (length > 0) {
-        for (i = 0; i < 8; i++)
-            tout[i] = (unsigned char)(tin[i] ^ iv[i]);
-
-        des_enc(tout,  tin, (uint8_t *)key + 0);
-        des_dec(tout, tout, (uint8_t *)key + 8);
-        des_enc(tout, tout, (uint8_t *)key + 0);
-
-        memcpy(iv, tout, 8);
-
-        tin  += 8;
-        tout += 8;
-        length -= 8;
-    }
-}
-
 void tdes_2key_dec(void *out, const void *in, size_t length, const void *key, unsigned char iv[8]) {
 
     if (length % 8) return;
@@ -439,6 +415,82 @@ void tdes_2key_dec(void *out, const void *in, size_t length, const void *key, un
     }
 }
 
+void tdes_2key_enc(void *out, const void *in, size_t length, const void *key, unsigned char iv[8]) {
+
+    if (length % 8) return;
+
+    uint8_t i;
+    uint8_t *tin = (uint8_t *) in;
+    uint8_t *tout = (uint8_t *) out;
+
+    while (length > 0) {
+        for (i = 0; i < 8; i++)
+            tout[i] = (unsigned char)(tin[i] ^ iv[i]);
+
+        des_enc(tout,  tin, (uint8_t *)key + 0);
+        des_dec(tout, tout, (uint8_t *)key + 8);
+        des_enc(tout, tout, (uint8_t *)key + 0);
+
+        memcpy(iv, tout, 8);
+
+        tin  += 8;
+        tout += 8;
+        length -= 8;
+    }
+}
+
+void tdes_3key_enc(void *out, const void *in, size_t length, const void *key, unsigned char iv[8]) {
+
+    if (length % 8) return;
+
+    uint8_t i;
+    uint8_t *tin = (uint8_t *) in;
+    uint8_t *tout = (uint8_t *) out;
+
+    while (length > 0) {
+        for (i = 0; i < 8; i++)
+            tout[i] = (unsigned char)(tin[i] ^ iv[i]);
+
+        des_enc(tout,  tin, (uint8_t *)key + 0);
+        des_dec(tout, tout, (uint8_t *)key + 8);
+        des_enc(tout, tout, (uint8_t *)key + 16);
+
+        memcpy(iv, tout, 8);
+
+        tin  += 8;
+        tout += 8;
+        length -= 8;
+    }
+}
+
+void tdes_3key_dec(void *out, const void *in, size_t length, const void *key, unsigned char iv[8]) {
+
+    if (length % 8) return;
+
+    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);
+
+        des_dec(tout,  tin, (uint8_t *)key + 0);
+        des_enc(tout, tout, (uint8_t *)key + 8);
+        des_dec(tout, tout, (uint8_t *)key + 16);
+
+        for (i = 0; i < 8; i++)
+            tout[i] = (unsigned char)(tout[i] ^ iv[i]);
+
+        memcpy(iv, temp, 8);
+
+        tin  += 8;
+        tout += 8;
+        length -= 8;
+    }
+}
+
+
 
 /******************************************************************************/
 
diff --git a/armsrc/des.h b/armsrc/des.h
index 8cf41b8ae..1a0549606 100644
--- a/armsrc/des.h
+++ b/armsrc/des.h
@@ -104,6 +104,8 @@ void tdes_dec(void *out, void *in, const uint8_t *key);
 
 void tdes_2key_enc(void *out, const void *in, size_t length, const void *key, unsigned char iv[8]);
 void tdes_2key_dec(void *out, const void *in, size_t length, const void *key, unsigned char iv[8]);
+void tdes_3key_enc(void *out, const void *in, size_t length, const void *key, unsigned char iv[8]);
+void tdes_3key_dec(void *out, const void *in, size_t length, const void *key, unsigned char iv[8]);
 
 // Copied from des.h in desfire imp.
 typedef unsigned long DES_KS[16][2];   /* Single-key DES key schedule */