diff --git a/library/aes.c b/library/aes.c
index 6d8cf2e..6a7e610 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -1035,6 +1035,24 @@
 }
 
 #if defined(MBEDTLS_CIPHER_MODE_CBC)
+
+#if defined(__ARM_NEON) && defined(__aarch64__)
+            /* Avoid using the NEON implementation of mbedtls_xor. Because of the dependency on
+             * the result for the next block in CBC, and the cost of transferring that data from
+             * NEON registers, it is faster to use the following on aarch64.
+             * For 32-bit arm, NEON should be faster. */
+#define CBC_XOR_16(r, a, b) do {                                           \
+            mbedtls_put_unaligned_uint64(r,                                    \
+                                         mbedtls_get_unaligned_uint64(a) ^     \
+                                         mbedtls_get_unaligned_uint64(b));     \
+            mbedtls_put_unaligned_uint64(r + 8,                                \
+                                         mbedtls_get_unaligned_uint64(a + 8) ^ \
+                                         mbedtls_get_unaligned_uint64(b + 8)); \
+} while (0)
+#else
+#define CBC_XOR_16(r, a, b) mbedtls_xor(r, a, b, 16)
+#endif
+
 /*
  * AES-CBC buffer encryption/decryption
  */
@@ -1077,8 +1095,7 @@
             if (ret != 0) {
                 goto exit;
             }
-
-            mbedtls_xor(output, output, iv, 16);
+            CBC_XOR_16(output, output, iv);
 
             memcpy(iv, temp, 16);
 
@@ -1088,7 +1105,7 @@
         }
     } else {
         while (length > 0) {
-            mbedtls_xor(output, input, ivp, 16);
+            CBC_XOR_16(output, input, ivp);
 
             ret = mbedtls_aes_crypt_ecb(ctx, mode, output, output);
             if (ret != 0) {