diff --git a/src/tf.c b/src/tf.c
index 59fdadc..b846088 100644
--- a/src/tf.c
+++ b/src/tf.c
@@ -48,7 +48,7 @@ THE SOFTWARE.
 
 
 #include "tf.h"
-
+#include "portable_endian.h"
 
 const uint8_t RS[4][8] = { { 0x01, 0xA4, 0x55, 0x87, 0x5A, 0x58, 0xDB, 0x9E, },
                            { 0xA4, 0x56, 0x82, 0xF3, 0x1E, 0xC6, 0x68, 0xE5, },
diff --git a/src/transform_aes.c b/src/transform_aes.c
index caf99ed..6f2c7dd 100644
--- a/src/transform_aes.c
+++ b/src/transform_aes.c
@@ -30,8 +30,8 @@
 #define AES_PREAMBLE_SIZE       (AES_BLOCK_SIZE)
 
 // cbc mode is being used with random value prepended to plaintext
-// instead of iv so, actual iv is null_iv
-const uint8_t null_iv[AES_IV_SIZE] = {0};
+// instead of iv so, actual iv is aes_null_iv
+const uint8_t aes_null_iv[AES_IV_SIZE] = {0};
 
 typedef struct transop_aes {
   aes_context_t       *ctx;
@@ -98,7 +98,7 @@ static int transop_encode_aes(n2n_trans_op_t * arg,
         // to slightly faster code than run-time dependant 'padding'
         memset (assembly + idx, 0, AES_BLOCK_SIZE);
 
-        aes_cbc_encrypt(outbuf, assembly, padded_len, null_iv, priv->ctx);
+        aes_cbc_encrypt(outbuf, assembly, padded_len, aes_null_iv, priv->ctx);
 
         if(padding) {
           // exchange last two cipher blocks
@@ -153,15 +153,15 @@ static int transop_decode_aes(n2n_trans_op_t * arg,
       //  write new penultimate block from buf
       memcpy(assembly + penultimate_block, buf, AES_BLOCK_SIZE);
       // regular cbc decryption on the re-arranged ciphertext
-      aes_cbc_decrypt(assembly, assembly, in_len + AES_BLOCK_SIZE - rest, null_iv, priv->ctx);
+      aes_cbc_decrypt(assembly, assembly, in_len + AES_BLOCK_SIZE - rest, aes_null_iv, priv->ctx);
       // check for expected zero padding and give a warning otherwise
-      if (memcmp(assembly + in_len, null_iv, AES_BLOCK_SIZE - rest)) {
+      if (memcmp(assembly + in_len, aes_null_iv, AES_BLOCK_SIZE - rest)) {
         traceEvent(TRACE_WARNING, "transop_decode_aes payload decryption failed with unexpected cipher text stealing padding");
         return -1;
       }
     } else {
       // regular cbc decryption on multiple block-sized payload
-      aes_cbc_decrypt(assembly, inbuf, in_len, null_iv, priv->ctx);
+      aes_cbc_decrypt(assembly, inbuf, in_len, aes_null_iv, priv->ctx);
     }
      len = in_len    - AES_PREAMBLE_SIZE;
      memcpy(outbuf,
diff --git a/src/transform_tf.c b/src/transform_tf.c
index e40c1d8..c9316b8 100644
--- a/src/transform_tf.c
+++ b/src/transform_tf.c
@@ -28,8 +28,8 @@
 #define TF_PREAMBLE_SIZE       (TF_BLOCK_SIZE)
 
 // cbc mode is being used with random value prepended to plaintext
-// instead of iv so, actual iv is null_iv
-const uint8_t null_iv[TF_IV_SIZE] = {0};
+// instead of iv so, actual iv is tf_null_iv
+const uint8_t tf_null_iv[TF_IV_SIZE] = {0};
 
 typedef struct transop_tf {
   tf_context_t       *ctx;
@@ -100,7 +100,7 @@ static int transop_encode_tf(n2n_trans_op_t * arg,
         // pad the following bytes with zero, fixed length (TF_BLOCK_SIZE) seems to compile
         // to slightly faster code than run-time dependant 'padding'
         memset (assembly + idx, 0, TF_BLOCK_SIZE);
-        tf_cbc_encrypt(outbuf, assembly, padded_len, null_iv, priv->ctx);
+        tf_cbc_encrypt(outbuf, assembly, padded_len, tf_null_iv, priv->ctx);
 
         if(padding) {
           // exchange last two cipher blocks
@@ -156,16 +156,16 @@ static int transop_decode_tf(n2n_trans_op_t * arg,
       memcpy(assembly + penultimate_block, buf, TF_BLOCK_SIZE);
       // regular cbc decryption on the re-arranged ciphertext
 
-      tf_cbc_decrypt(assembly, assembly, in_len + TF_BLOCK_SIZE - rest, null_iv, priv->ctx);
+      tf_cbc_decrypt(assembly, assembly, in_len + TF_BLOCK_SIZE - rest, tf_null_iv, priv->ctx);
 
       // check for expected zero padding and give a warning otherwise
-      if (memcmp(assembly + in_len, null_iv, TF_BLOCK_SIZE - rest)) {
+      if (memcmp(assembly + in_len, tf_null_iv, TF_BLOCK_SIZE - rest)) {
         traceEvent(TRACE_WARNING, "transop_decode_tf payload decryption failed with unexpected cipher text stealing padding");
         return -1;
       }
     } else {
       // regular cbc decryption on multiple block-sized payload
-      tf_cbc_decrypt(assembly, inbuf, in_len, null_iv, priv->ctx);
+      tf_cbc_decrypt(assembly, inbuf, in_len, tf_null_iv, priv->ctx);
     }
     len = in_len    - TF_PREAMBLE_SIZE;
     memcpy(outbuf,