diff --git a/src/templates/js/cn_util.js b/src/templates/js/cn_util.js
index 312377f..73d7887 100755
--- a/src/templates/js/cn_util.js
+++ b/src/templates/js/cn_util.js
@@ -291,7 +291,7 @@ var cnUtil = (function(initConfig) {
     this.sc_reduce = function(hex) {
         var input = hextobin(hex);
         if (input.length !== 64) {
-            throw "Invalid input length";
+            throw "sc_reduce: Invalid hextobin(hex) input length";
         }
         var mem = Module._malloc(64);
         Module.HEAPU8.set(input, mem);
@@ -304,7 +304,7 @@ var cnUtil = (function(initConfig) {
     this.sc_reduce32 = function(hex) {
         var input = hextobin(hex);
         if (input.length !== 32) {
-            throw "Invalid input length";
+            throw "sc_reduce32: Invalid hextobin(hex) input length";
         }
         var mem = Module._malloc(32);
         Module.HEAPU8.set(input, mem);
@@ -319,7 +319,7 @@ var cnUtil = (function(initConfig) {
             inlen = Math.floor(input.length / 2);
         }*/
         if (input.length % 2 !== 0 || !this.valid_hex(input)) {
-            throw "Input invalid";
+            throw "cn_fast_hash: Input invalid";
         }
         //update to use new keccak impl (approx 45x faster)
         //var state = this.keccak(input, inlen, HASH_STATE_BYTES);
@@ -349,7 +349,7 @@ var cnUtil = (function(initConfig) {
 
     this.sec_key_to_pub = function(sec) {
         if (sec.length !== 64) {
-            throw "Invalid sec length";
+            throw "sec_key_to_pub: Invalid sec length";
         }
         return bintohex(nacl.ll.ge_scalarmult_base(hextobin(sec)));
     };
@@ -388,7 +388,7 @@ var cnUtil = (function(initConfig) {
     };*/
     this.ge_scalarmult = function(pub, sec) {
         if (pub.length !== 64 || sec.length !== 64) {
-            throw "Invalid input length";
+            throw "ge_scalarmult: Invalid pub or sec input lengths";
         }
         return bintohex(nacl.ll.ge_scalarmult(hextobin(pub), hextobin(sec)));
     };
@@ -413,7 +413,7 @@ var cnUtil = (function(initConfig) {
 
 
     this.decrypt_payment_id = function(payment_id8, tx_public_key, acc_prv_view_key) {
-        if (payment_id8.length !== 16) throw "Invalid input length!";  
+        if (payment_id8.length !== 16) throw "decrypt_payment_id: Invalid payment_id8 length!";
 
         var key_derivation = this.generate_key_derivation(tx_public_key, acc_prv_view_key);    
 
@@ -438,7 +438,7 @@ var cnUtil = (function(initConfig) {
     // Generate keypair from seed 2
     // as in simplewallet
     this.generate_keys = function(seed) {
-        if (seed.length !== 64) throw "Invalid input length!";
+        if (seed.length !== 64) throw "generate_keys: Invalid seed input length!";
         var sec = this.sc_reduce32(seed);
         var pub = this.sec_key_to_pub(sec);
         return {
@@ -605,7 +605,7 @@ var cnUtil = (function(initConfig) {
 
     this.generate_key_derivation = function(pub, sec) {
         if (pub.length !== 64 || sec.length !== 64) {
-            throw "Invalid input length";
+            throw "generate_key_derivation: Invalid pub or sec keys lengths";
         }
         var P = this.ge_scalarmult(pub, sec);
         return this.ge_scalarmult(P, d2s(8)); //mul8 to ensure group
@@ -614,7 +614,7 @@ var cnUtil = (function(initConfig) {
     this.derivation_to_scalar = function(derivation, output_index) {
         var buf = "";
         if (derivation.length !== (STRUCT_SIZES.EC_POINT * 2)) {
-            throw "Invalid derivation length!";
+            throw "derivation_to_scalar: Invalid derivation length!";
         }
         buf += derivation;
         var enc = encode_varint(output_index);
@@ -627,7 +627,7 @@ var cnUtil = (function(initConfig) {
 
     this.derive_secret_key = function(derivation, out_index, sec) {
         if (derivation.length !== 64 || sec.length !== 64) {
-            throw "Invalid input length!";
+            throw "derive_secret_key: Invalid derivation or sec input length!";
         }
         var scalar_m = Module._malloc(STRUCT_SIZES.EC_SCALAR);
         var scalar_b = hextobin(this.derivation_to_scalar(derivation, out_index));
@@ -685,7 +685,7 @@ var cnUtil = (function(initConfig) {
 
     this.derive_public_key = function(derivation, out_index, pub) {
         if (derivation.length !== 64 || pub.length !== 64) {
-            throw "Invalid input length!";
+            throw "derive_public_key: Invalid derivation or pub key input lengths!";
         }
         var s = this.derivation_to_scalar(derivation, out_index);
         return bintohex(nacl.ll.ge_add(hextobin(pub), hextobin(this.ge_scalarmult_base(s))));
@@ -693,7 +693,7 @@ var cnUtil = (function(initConfig) {
 
     this.hash_to_ec = function(key) {
         if (key.length !== (KEY_SIZE * 2)) {
-            throw "Invalid input length";
+            throw "hash_to_ec: Invalid key input length";
         }
         var h_m = Module._malloc(HASH_SIZE);
         var point_m = Module._malloc(STRUCT_SIZES.GE_P2);
@@ -715,7 +715,7 @@ var cnUtil = (function(initConfig) {
     //returns a 32 byte point via "ge_p3_tobytes" rather than a 160 byte "p3", otherwise same as above;
     this.hash_to_ec_2 = function(key) {
         if (key.length !== (KEY_SIZE * 2)) {
-            throw "Invalid input length";
+            throw "hash_to_ec_2: Invalid key input length";
         }
         var h_m = Module._malloc(HASH_SIZE);
         var point_m = Module._malloc(STRUCT_SIZES.GE_P2);
@@ -739,7 +739,7 @@ var cnUtil = (function(initConfig) {
 
     this.generate_key_image_2 = function(pub, sec) {
         if (!pub || !sec || pub.length !== 64 || sec.length !== 64) {
-            throw "Invalid input length";
+            throw "generate_key_image_2: Invalid pub or sec keys input length";
         }
         var pub_m = Module._malloc(KEY_SIZE);
         var sec_m = Module._malloc(KEY_SIZE);
@@ -863,7 +863,7 @@ var cnUtil = (function(initConfig) {
 
     this.ge_add = function(p1, p2) {
         if (p1.length !== 64 || p2.length !== 64) {
-            throw "Invalid input length!";
+            throw "ge_add: Invalid p1 or p2 input lengths!";
         }
         return bintohex(nacl.ll.ge_add(hextobin(p1), hextobin(p2)));
     };
@@ -877,7 +877,7 @@ var cnUtil = (function(initConfig) {
     //adds two scalars together
     this.sc_add = function(scalar1, scalar2) {
         if (scalar1.length !== 64 || scalar2.length !== 64) {
-            throw "Invalid input length!";
+            throw "sc_add: Invalid scalar1 or scalar2 input length!";
         }
         var scalar1_m = Module._malloc(STRUCT_SIZES.EC_SCALAR);
         var scalar2_m = Module._malloc(STRUCT_SIZES.EC_SCALAR);
@@ -895,7 +895,7 @@ var cnUtil = (function(initConfig) {
     //subtracts one scalar from another
     this.sc_sub = function(scalar1, scalar2) {
         if (scalar1.length !== 64 || scalar2.length !== 64) {
-            throw "Invalid input length!";
+            throw "sc_sub: Invalid scalar1 or scalar2 input lengths!";
         }
         var scalar1_m = Module._malloc(STRUCT_SIZES.EC_SCALAR);
         var scalar2_m = Module._malloc(STRUCT_SIZES.EC_SCALAR);
@@ -913,7 +913,7 @@ var cnUtil = (function(initConfig) {
     //fun mul function
     this.sc_mul = function(scalar1, scalar2) {
         if (scalar1.length !== 64 || scalar2.length !== 64) {
-            throw "Invalid input length!";
+            throw "sc_mul: Invalid scalar1 or scalar2 input lengths!";
         }
         return d2s(JSBigInt(s2d(scalar1)).multiply(JSBigInt(s2d(scalar2))).remainder(l).toString());
     };
@@ -971,7 +971,7 @@ var cnUtil = (function(initConfig) {
 
     this.ge_double_scalarmult_base_vartime = function(c, P, r) {
         if (c.length !== 64 || P.length !== 64 || r.length !== 64) {
-            throw "Invalid input length!";
+            throw "ge_double_scalarmult_base_vartime: Invalid c, P or r input lengths!";
         }
         return bintohex(nacl.ll.ge_double_scalarmult_base_vartime(hextobin(c), hextobin(P), hextobin(r)));
     };
@@ -1012,7 +1012,7 @@ var cnUtil = (function(initConfig) {
 
     this.ge_double_scalarmult_postcomp_vartime = function(r, P, c, I) {
         if (c.length !== 64 || P.length !== 64 || r.length !== 64 || I.length !== 64) {
-            throw "Invalid input length!";
+            throw "ge_double_scalarmult_postcomp_vartime: Invalid r, p, c or I input lengths!";
         }
         var Pb = this.hash_to_ec_2(P);
         return bintohex(nacl.ll.ge_double_scalarmult_postcomp_vartime(hextobin(r), hextobin(Pb), hextobin(c), hextobin(I)));
diff --git a/src/templates/partials/tx_details.html b/src/templates/partials/tx_details.html
index f9d5bf6..209a5ea 100644
--- a/src/templates/partials/tx_details.html
+++ b/src/templates/partials/tx_details.html
@@ -173,6 +173,8 @@
 
                 var tx_public_key = $("#tx_pub_key").text();
 
+                // when we process multi-ouput tx, it can have extra public keys
+                // due to sub-addresses
                 var add_tx_pub_keys = $("#add_tx_pub_keys").text().split(';').slice(0, -1);
 
                 console.log("add_tx_pub_keys: ", add_tx_pub_keys);
@@ -190,6 +192,8 @@
                         return;
                     }
 
+                    // not used when decoding, but used when proving.
+                    // so we just use array here
                     multiple_tx_secret_keys = [];
 
                     try {
@@ -199,7 +203,7 @@
                                       add_tx_pub_keys, multiple_tx_secret_keys, false);
                     } catch(err){
                         console.log(err);
-                        $("#decode-prove-results").html('<h4>Error:' + err.message + '</h4>' );
+                        $("#decode-prove-results").html('<h4>Error: ' + err + '</h4>' );
                     }
                 });
 
@@ -216,7 +220,7 @@
                     // when using subaddress, there can be more than one tx_prv_key
                     var multiple_tx_prv_keys = parse_str_secret_key(tx_prv_key);
 
-                    console.log("multiple_tx_prv_keys: ", multiple_tx_prv_keys);
+                    //console.log("multiple_tx_prv_keys: ", multiple_tx_prv_keys);
 
 
                     try {
@@ -226,13 +230,13 @@
                                       add_tx_pub_keys, multiple_tx_prv_keys, true);
                     } catch(err){
                         console.log(err);
-                        $("#decode-prove-results").html('<h4>Error:' + err.message + '</h4>' );
+                        $("#decode-prove-results").html('<h4>Error: ' + err + '</h4>' );
                     }
                 });
 
             });
 
-            // based on C++ by stoffu
+            // based on C++ code by stoffu
             function parse_str_secret_key(key_str) {
 
                 var multiple_tx_secret_keys = [];
@@ -303,17 +307,8 @@
                     var output_pub_key = output.target.key;
                     var amount         = output.amount;
 
-                    // var pubkey_generated = (add_tx_pub_keys
-                    //                        ? derive_public_key(add_key_derivation[output_idx],
-                    //                                            output_idx, address_pub_key)
-                    //                        : derive_public_key(key_derivation, output_idx, address_pub_key));
-
-
                     var pubkey_generated = derive_public_key(key_derivation, output_idx, address_pub_key);
 
-
-                    //console.log(pubkey_generated);
-
                     var mine_output = (output_pub_key == pubkey_generated);
 
                     var with_additional = false;