Doug Doug - 2 months ago 7
Java Question

AES JavaScript & Java

Ok, I'm using the following AES JavaScript library:

http://www.movable-type.co.uk/scripts/aes.html

I'm trying to write Java that can decrypt the resulting packaged that was encrypted by JavaScript, but I keep doing something wrong and keep getting all sorts of errors:

e.g. javax.crypto.IllegalBlockSizeException: Input length must be multiple of 16 when decrypting with padded cipher

Below is my Java code. Can anyone please help point me in the right direction?

package com.thebodgeitstore.util;

import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.util.regex.Pattern;
import javax.crypto.*;
import javax.crypto.spec.*;


public class AES {
private SecretKeySpec key;
private Cipher cipher;
private int size = 128;

public AES() throws NoSuchAlgorithmException, NoSuchPaddingException{
KeyGenerator kgen = KeyGenerator.getInstance("AES");
kgen.init(size); // 192 and 256 bits may not be available
SecretKey skey = kgen.generateKey();
byte[] raw = skey.getEncoded();
key = new SecretKeySpec(raw, "AES");
cipher = Cipher.getInstance("AES");
}

public void setKey(String keyText){
byte[] bText = new byte[size];
bText = keyText.getBytes();
key = new SecretKeySpec(bText, "AES");
}

public String encrypt(String message) throws InvalidKeyException, IllegalBlockSizeException, BadPaddingException{
cipher.init(Cipher.ENCRYPT_MODE, key);
byte[] encrypted = cipher.doFinal(message.getBytes());
return byteArrayToHexString(encrypted);
}
public String decrypt(String hexCiphertext) throws IllegalBlockSizeException, BadPaddingException, InvalidKeyException{
cipher.init(Cipher.DECRYPT_MODE, key);
byte[] decrypted = cipher.doFinal(hexStringToByteArray(hexCiphertext));
return byteArrayToHexString(decrypted);
}

private static String byteArrayToHexString( byte [] raw ) {
String hex = "0x";
String s = new String(raw);
for(int x = 0; x < s.length(); x++){
char[] t = s.substring(x, x + 1).toCharArray();
hex += Integer.toHexString((int) t[0]).toUpperCase();
}
return hex;
}

private static byte[] hexStringToByteArray(String hex) {
Pattern replace = Pattern.compile("^0x");
String s = replace.matcher(hex).replaceAll("");

byte[] b = new byte[s.length() / 2];
for (int i = 0; i < b.length; i++){
int index = i * 2;
int v = Integer.parseInt(s.substring(index, index + 2), 16);
b[i] = (byte)v;
}
return b;
}


}


Javascript code I'm using:

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* AES implementation in JavaScript (c) Chris Veness 2005-2011 */
/* - see http://csrc.nist.gov/publications/PubsFIPS.html#197 */
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

var Aes = {}; // Aes namespace

/**
* AES Cipher function: encrypt 'input' state with Rijndael algorithm
* applies Nr rounds (10/12/14) using key schedule w for 'add round key' stage
*
* @param {Number[]} input 16-byte (128-bit) input state array
* @param {Number[][]} w Key schedule as 2D byte-array (Nr+1 x Nb bytes)
* @returns {Number[]} Encrypted output state array
*/
Aes.cipher = function(input, w) { // main Cipher function [§5.1]
var Nb = 4; // block size (in words): no of columns in state (fixed at 4 for AES)
var Nr = w.length/Nb - 1; // no of rounds: 10/12/14 for 128/192/256-bit keys

var state = [[],[],[],[]]; // initialise 4xNb byte-array 'state' with input [§3.4]
for (var i=0; i<4*Nb; i++) state[i%4][Math.floor(i/4)] = input[i];

state = Aes.addRoundKey(state, w, 0, Nb);

for (var round=1; round<Nr; round++) {
state = Aes.subBytes(state, Nb);
state = Aes.shiftRows(state, Nb);
state = Aes.mixColumns(state, Nb);
state = Aes.addRoundKey(state, w, round, Nb);
}

state = Aes.subBytes(state, Nb);
state = Aes.shiftRows(state, Nb);
state = Aes.addRoundKey(state, w, Nr, Nb);

var output = new Array(4*Nb); // convert state to 1-d array before returning [§3.4]
for (var i=0; i<4*Nb; i++) output[i] = state[i%4][Math.floor(i/4)];
return output;
}

/**
* Perform Key Expansion to generate a Key Schedule
*
* @param {Number[]} key Key as 16/24/32-byte array
* @returns {Number[][]} Expanded key schedule as 2D byte-array (Nr+1 x Nb bytes)
*/
Aes.keyExpansion = function(key) { // generate Key Schedule (byte-array Nr+1 x Nb) from Key [§5.2]
var Nb = 4; // block size (in words): no of columns in state (fixed at 4 for AES)
var Nk = key.length/4 // key length (in words): 4/6/8 for 128/192/256-bit keys
var Nr = Nk + 6; // no of rounds: 10/12/14 for 128/192/256-bit keys

var w = new Array(Nb*(Nr+1));
var temp = new Array(4);

for (var i=0; i<Nk; i++) {
var r = [key[4*i], key[4*i+1], key[4*i+2], key[4*i+3]];
w[i] = r;
}

for (var i=Nk; i<(Nb*(Nr+1)); i++) {
w[i] = new Array(4);
for (var t=0; t<4; t++) temp[t] = w[i-1][t];
if (i % Nk == 0) {
temp = Aes.subWord(Aes.rotWord(temp));
for (var t=0; t<4; t++) temp[t] ^= Aes.rCon[i/Nk][t];
} else if (Nk > 6 && i%Nk == 4) {
temp = Aes.subWord(temp);
}
for (var t=0; t<4; t++) w[i][t] = w[i-Nk][t] ^ temp[t];
}

return w;
}

/*
* ---- remaining routines are private, not called externally ----
*/

Aes.subBytes = function(s, Nb) { // apply SBox to state S [§5.1.1]
for (var r=0; r<4; r++) {
for (var c=0; c<Nb; c++) s[r][c] = Aes.sBox[s[r][c]];
}
return s;
}

Aes.shiftRows = function(s, Nb) { // shift row r of state S left by r bytes [§5.1.2]
var t = new Array(4);
for (var r=1; r<4; r++) {
for (var c=0; c<4; c++) t[c] = s[r][(c+r)%Nb]; // shift into temp copy
for (var c=0; c<4; c++) s[r][c] = t[c]; // and copy back
} // note that this will work for Nb=4,5,6, but not 7,8 (always 4 for AES):
return s; // see asmaes.sourceforge.net/rijndael/rijndaelImplementation.pdf
}

Aes.mixColumns = function(s, Nb) { // combine bytes of each col of state S [§5.1.3]
for (var c=0; c<4; c++) {
var a = new Array(4); // 'a' is a copy of the current column from 's'
var b = new Array(4); // 'b' is a•{02} in GF(2^8)
for (var i=0; i<4; i++) {
a[i] = s[i][c];
b[i] = s[i][c]&0x80 ? s[i][c]<<1 ^ 0x011b : s[i][c]<<1;

}
// a[n] ^ b[n] is a•{03} in GF(2^8)
s[0][c] = b[0] ^ a[1] ^ b[1] ^ a[2] ^ a[3]; // 2*a0 + 3*a1 + a2 + a3
s[1][c] = a[0] ^ b[1] ^ a[2] ^ b[2] ^ a[3]; // a0 * 2*a1 + 3*a2 + a3
s[2][c] = a[0] ^ a[1] ^ b[2] ^ a[3] ^ b[3]; // a0 + a1 + 2*a2 + 3*a3
s[3][c] = a[0] ^ b[0] ^ a[1] ^ a[2] ^ b[3]; // 3*a0 + a1 + a2 + 2*a3
}
return s;
}

Aes.addRoundKey = function(state, w, rnd, Nb) { // xor Round Key into state S [§5.1.4]
for (var r=0; r<4; r++) {
for (var c=0; c<Nb; c++) state[r][c] ^= w[rnd*4+c][r];
}
return state;
}

Aes.subWord = function(w) { // apply SBox to 4-byte word w
for (var i=0; i<4; i++) w[i] = Aes.sBox[w[i]];
return w;
}

Aes.rotWord = function(w) { // rotate 4-byte word w left by one byte
var tmp = w[0];
for (var i=0; i<3; i++) w[i] = w[i+1];
w[3] = tmp;
return w;
}

// sBox is pre-computed multiplicative inverse in GF(2^8) used in subBytes and keyExpansion [§5.1.1]
Aes.sBox = [0x63,0x7c,0x77,0x7b,0xf2,0x6b,0x6f,0xc5,0x30,0x01,0x67,0x2b,0xfe,0xd7,0xab,0x76,
0xca,0x82,0xc9,0x7d,0xfa,0x59,0x47,0xf0,0xad,0xd4,0xa2,0xaf,0x9c,0xa4,0x72,0xc0,
0xb7,0xfd,0x93,0x26,0x36,0x3f,0xf7,0xcc,0x34,0xa5,0xe5,0xf1,0x71,0xd8,0x31,0x15,
0x04,0xc7,0x23,0xc3,0x18,0x96,0x05,0x9a,0x07,0x12,0x80,0xe2,0xeb,0x27,0xb2,0x75,
0x09,0x83,0x2c,0x1a,0x1b,0x6e,0x5a,0xa0,0x52,0x3b,0xd6,0xb3,0x29,0xe3,0x2f,0x84,
0x53,0xd1,0x00,0xed,0x20,0xfc,0xb1,0x5b,0x6a,0xcb,0xbe,0x39,0x4a,0x4c,0x58,0xcf,
0xd0,0xef,0xaa,0xfb,0x43,0x4d,0x33,0x85,0x45,0xf9,0x02,0x7f,0x50,0x3c,0x9f,0xa8,
0x51,0xa3,0x40,0x8f,0x92,0x9d,0x38,0xf5,0xbc,0xb6,0xda,0x21,0x10,0xff,0xf3,0xd2,
0xcd,0x0c,0x13,0xec,0x5f,0x97,0x44,0x17,0xc4,0xa7,0x7e,0x3d,0x64,0x5d,0x19,0x73,
0x60,0x81,0x4f,0xdc,0x22,0x2a,0x90,0x88,0x46,0xee,0xb8,0x14,0xde,0x5e,0x0b,0xdb,
0xe0,0x32,0x3a,0x0a,0x49,0x06,0x24,0x5c,0xc2,0xd3,0xac,0x62,0x91,0x95,0xe4,0x79,
0xe7,0xc8,0x37,0x6d,0x8d,0xd5,0x4e,0xa9,0x6c,0x56,0xf4,0xea,0x65,0x7a,0xae,0x08,
0xba,0x78,0x25,0x2e,0x1c,0xa6,0xb4,0xc6,0xe8,0xdd,0x74,0x1f,0x4b,0xbd,0x8b,0x8a,
0x70,0x3e,0xb5,0x66,0x48,0x03,0xf6,0x0e,0x61,0x35,0x57,0xb9,0x86,0xc1,0x1d,0x9e,
0xe1,0xf8,0x98,0x11,0x69,0xd9,0x8e,0x94,0x9b,0x1e,0x87,0xe9,0xce,0x55,0x28,0xdf,
0x8c,0xa1,0x89,0x0d,0xbf,0xe6,0x42,0x68,0x41,0x99,0x2d,0x0f,0xb0,0x54,0xbb,0x16];

// rCon is Round Constant used for the Key Expansion [1st col is 2^(r-1) in GF(2^8)] [§5.2]
Aes.rCon = [ [0x00, 0x00, 0x00, 0x00],
[0x01, 0x00, 0x00, 0x00],
[0x02, 0x00, 0x00, 0x00],
[0x04, 0x00, 0x00, 0x00],
[0x08, 0x00, 0x00, 0x00],
[0x10, 0x00, 0x00, 0x00],
[0x20, 0x00, 0x00, 0x00],
[0x40, 0x00, 0x00, 0x00],
[0x80, 0x00, 0x00, 0x00],
[0x1b, 0x00, 0x00, 0x00],
[0x36, 0x00, 0x00, 0x00] ];


/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* AES Counter-mode implementation in JavaScript (c) Chris Veness 2005-2011 */
/* - see http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf */
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

Aes.Ctr = {}; // Aes.Ctr namespace: a subclass or extension of Aes

/**
* Encrypt a text using AES encryption in Counter mode of operation
*
* Unicode multi-byte character safe
*
* @param {String} plaintext Source text to be encrypted
* @param {String} password The password to use to generate a key
* @param {Number} nBits Number of bits to be used in the key (128, 192, or 256)
* @returns {string} Encrypted text
*/
Aes.Ctr.encrypt = function(plaintext, password, nBits) {
var blockSize = 16; // block size fixed at 16 bytes / 128 bits (Nb=4) for AES
if (!(nBits==128 || nBits==192 || nBits==256)) return ''; // standard allows 128/192/256 bit keys
plaintext = Utf8.encode(plaintext);
password = Utf8.encode(password);
//var t = new Date(); // timer

// use AES itself to encrypt password to get cipher key (using plain password as source for key
// expansion) - gives us well encrypted key (though hashed key might be preferred for prod'n use)
var nBytes = nBits/8; // no bytes in key (16/24/32)
var pwBytes = new Array(nBytes);
for (var i=0; i<nBytes; i++) { // use 1st 16/24/32 chars of password for key
pwBytes[i] = isNaN(password.charCodeAt(i)) ? 0 : password.charCodeAt(i);
}
var key = Aes.cipher(pwBytes, Aes.keyExpansion(pwBytes)); // gives us 16-byte key
key = key.concat(key.slice(0, nBytes-16)); // expand key to 16/24/32 bytes long

// initialise 1st 8 bytes of counter block with nonce (NIST SP800-38A §B.2): [0-1] = millisec,
// [2-3] = random, [4-7] = seconds, together giving full sub-millisec uniqueness up to Feb 2106
var counterBlock = new Array(blockSize);

var nonce = (new Date()).getTime(); // timestamp: milliseconds since 1-Jan-1970
var nonceMs = nonce%1000;
var nonceSec = Math.floor(nonce/1000);
var nonceRnd = Math.floor(Math.random()*0xffff);

for (var i=0; i<2; i++) counterBlock[i] = (nonceMs >>> i*8) & 0xff;
for (var i=0; i<2; i++) counterBlock[i+2] = (nonceRnd >>> i*8) & 0xff;
for (var i=0; i<4; i++) counterBlock[i+4] = (nonceSec >>> i*8) & 0xff;

// and convert it to a string to go on the front of the ciphertext
var ctrTxt = '';
for (var i=0; i<8; i++) ctrTxt += String.fromCharCode(counterBlock[i]);

// generate key schedule - an expansion of the key into distinct Key Rounds for each round
var keySchedule = Aes.keyExpansion(key);

var blockCount = Math.ceil(plaintext.length/blockSize);
var ciphertxt = new Array(blockCount); // ciphertext as array of strings

for (var b=0; b<blockCount; b++) {
// set counter (block #) in last 8 bytes of counter block (leaving nonce in 1st 8 bytes)
// done in two stages for 32-bit ops: using two words allows us to go past 2^32 blocks (68GB)
for (var c=0; c<4; c++) counterBlock[15-c] = (b >>> c*8) & 0xff;
for (var c=0; c<4; c++) counterBlock[15-c-4] = (b/0x100000000 >>> c*8)

var cipherCntr = Aes.cipher(counterBlock, keySchedule); // -- encrypt counter block --

// block size is reduced on final block
var blockLength = b<blockCount-1 ? blockSize : (plaintext.length-1)%blockSize+1;
var cipherChar = new Array(blockLength);

for (var i=0; i<blockLength; i++) { // -- xor plaintext with ciphered counter char-by-char --
cipherChar[i] = cipherCntr[i] ^ plaintext.charCodeAt(b*blockSize+i);
cipherChar[i] = String.fromCharCode(cipherChar[i]);
}
ciphertxt[b] = cipherChar.join('');
}

// Array.join is more efficient than repeated string concatenation in IE
var ciphertext = ctrTxt + ciphertxt.join('');
ciphertext = stringToHex(ciphertext); // encode in base64

//alert((new Date()) - t);
return ciphertext;
}

/**
* Decrypt a text encrypted by AES in counter mode of operation
*
* @param {String} ciphertext Source text to be encrypted
* @param {String} password The password to use to generate a key
* @param {Number} nBits Number of bits to be used in the key (128, 192, or 256)
* @returns {String} Decrypted text
*/
Aes.Ctr.decrypt = function(ciphertext, password, nBits) {
var blockSize = 16; // block size fixed at 16 bytes / 128 bits (Nb=4) for AES
if (!(nBits==128 || nBits==192 || nBits==256)) return ''; // standard allows 128/192/256 bit keys
ciphertext = hexToString(ciphertext);
password = Utf8.encode(password);
//var t = new Date(); // timer

// use AES to encrypt password (mirroring encrypt routine)
var nBytes = nBits/8; // no bytes in key
var pwBytes = new Array(nBytes);
for (var i=0; i<nBytes; i++) {
pwBytes[i] = isNaN(password.charCodeAt(i)) ? 0 : password.charCodeAt(i);
}
var key = Aes.cipher(pwBytes, Aes.keyExpansion(pwBytes));
key = key.concat(key.slice(0, nBytes-16)); // expand key to 16/24/32 bytes long

// recover nonce from 1st 8 bytes of ciphertext
var counterBlock = new Array(8);
ctrTxt = ciphertext.slice(0, 8);
for (var i=0; i<8; i++) counterBlock[i] = ctrTxt.charCodeAt(i);

// generate key schedule
var keySchedule = Aes.keyExpansion(key);

// separate ciphertext into blocks (skipping past initial 8 bytes)
var nBlocks = Math.ceil((ciphertext.length-8) / blockSize);
var ct = new Array(nBlocks);
for (var b=0; b<nBlocks; b++) ct[b] = ciphertext.slice(8+b*blockSize, 8+b*blockSize+blockSize);
ciphertext = ct; // ciphertext is now array of block-length strings

// plaintext will get generated block-by-block into array of block-length strings
var plaintxt = new Array(ciphertext.length);

for (var b=0; b<nBlocks; b++) {
// set counter (block #) in last 8 bytes of counter block (leaving nonce in 1st 8 bytes)
for (var c=0; c<4; c++) counterBlock[15-c] = ((b) >>> c*8) & 0xff;
for (var c=0; c<4; c++) counterBlock[15-c-4] = (((b+1)/0x100000000-1) >>> c*8) & 0xff;

var cipherCntr = Aes.cipher(counterBlock, keySchedule); // encrypt counter block

var plaintxtByte = new Array(ciphertext[b].length);
for (var i=0; i<ciphertext[b].length; i++) {
// -- xor plaintxt with ciphered counter byte-by-byte --
plaintxtByte[i] = cipherCntr[i] ^ ciphertext[b].charCodeAt(i);
plaintxtByte[i] = String.fromCharCode(plaintxtByte[i]);
}
plaintxt[b] = plaintxtByte.join('');
}

// join array of blocks into single plaintext string
var plaintext = plaintxt.join('');
plaintext = Utf8.decode(plaintext); // decode from UTF8 back to Unicode multi-byte chars

//alert((new Date()) - t);
return plaintext;
}


/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* Base64 class: Base 64 encoding / decoding (c) Chris Veness 2002-2011 */
/* note: depends on Utf8 class */
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

var Base64 = {}; // Base64 namespace

Base64.code = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

/**
* Encode string into Base64, as defined by RFC 4648 [http://tools.ietf.org/html/rfc4648]
* (instance method extending String object). As per RFC 4648, no newlines are added.
*
* @param {String} str The string to be encoded as base-64
* @param {Boolean} [utf8encode=false] Flag to indicate whether str is Unicode string to be encoded
* to UTF8 before conversion to base64; otherwise string is assumed to be 8-bit characters
* @returns {String} Base64-encoded string
*/
Base64.encode = function(str, utf8encode) { // http://tools.ietf.org/html/rfc4648
utf8encode = (typeof utf8encode == 'undefined') ? false : utf8encode;
var o1, o2, o3, bits, h1, h2, h3, h4, e=[], pad = '', c, plain, coded;
var b64 = Base64.code;

plain = utf8encode ? str.encodeUTF8() : str;

c = plain.length % 3; // pad string to length of multiple of 3
if (c > 0) { while (c++ < 3) { pad += '='; plain += '\0'; } }
// note: doing padding here saves us doing special-case packing for trailing 1 or 2 chars

for (c=0; c<plain.length; c+=3) { // pack three octets into four hexets
o1 = plain.charCodeAt(c);
o2 = plain.charCodeAt(c+1);
o3 = plain.charCodeAt(c+2);

bits = o1<<16 | o2<<8 | o3;

h1 = bits>>18 & 0x3f;
h2 = bits>>12 & 0x3f;
h3 = bits>>6 & 0x3f;
h4 = bits & 0x3f;

// use hextets to index into code string
e[c/3] = b64.charAt(h1) + b64.charAt(h2) + b64.charAt(h3) + b64.charAt(h4);
}
coded = e.join(''); // join() is far faster than repeated string concatenation in IE

// replace 'A's from padded nulls with '='s
coded = coded.slice(0, coded.length-pad.length) + pad;

return coded;
}

/**
* Decode string from Base64, as defined by RFC 4648 [http://tools.ietf.org/html/rfc4648]
* (instance method extending String object). As per RFC 4648, newlines are not catered for.
*
* @param {String} str The string to be decoded from base-64
* @param {Boolean} [utf8decode=false] Flag to indicate whether str is Unicode string to be decoded
* from UTF8 after conversion from base64
* @returns {String} decoded string
*/
Base64.decode = function(str, utf8decode) {
utf8decode = (typeof utf8decode == 'undefined') ? false : utf8decode;
var o1, o2, o3, h1, h2, h3, h4, bits, d=[], plain, coded;
var b64 = Base64.code;

coded = utf8decode ? str.decodeUTF8() : str;


for (var c=0; c<coded.length; c+=4) { // unpack four hexets into three octets
h1 = b64.indexOf(coded.charAt(c));
h2 = b64.indexOf(coded.charAt(c+1));
h3 = b64.indexOf(coded.charAt(c+2));
h4 = b64.indexOf(coded.charAt(c+3));

bits = h1<<18 | h2<<12 | h3<<6 | h4;

o1 = bits>>>16 & 0xff;
o2 = bits>>>8 & 0xff;
o3 = bits & 0xff;

d[c/4] = String.fromCharCode(o1, o2, o3);
// check for padding
if (h4 == 0x40) d[c/4] = String.fromCharCode(o1, o2);
if (h3 == 0x40) d[c/4] = String.fromCharCode(o1);
}
plain = d.join(''); // join() is far faster than repeated string concatenation in IE

return utf8decode ? plain.decodeUTF8() : plain;
}


/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* Utf8 class: encode / decode between multi-byte Unicode characters and UTF-8 multiple */
/* single-byte character encoding (c) Chris Veness 2002-2011 */
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

var Utf8 = {}; // Utf8 namespace

/**
* Encode multi-byte Unicode string into utf-8 multiple single-byte characters
* (BMP / basic multilingual plane only)
*
* Chars in range U+0080 - U+07FF are encoded in 2 chars, U+0800 - U+FFFF in 3 chars
*
* @param {String} strUni Unicode string to be encoded as UTF-8
* @returns {String} encoded string
*/
Utf8.encode = function(strUni) {
// use regular expressions & String.replace callback function for better efficiency
// than procedural approaches
var strUtf = strUni.replace(
/[\u0080-\u07ff]/g, // U+0080 - U+07FF => 2 bytes 110yyyyy, 10zzzzzz
function(c) {
var cc = c.charCodeAt(0);
return String.fromCharCode(0xc0 | cc>>6, 0x80 | cc&0x3f); }
);
strUtf = strUtf.replace(
/[\u0800-\uffff]/g, // U+0800 - U+FFFF => 3 bytes 1110xxxx, 10yyyyyy, 10zzzzzz
function(c) {
var cc = c.charCodeAt(0);
return String.fromCharCode(0xe0 | cc>>12, 0x80 | cc>>6&0x3F, 0x80 | cc&0x3f); }
);
return strUtf;
}

/**
* Decode utf-8 encoded string back into multi-byte Unicode characters
*
* @param {String} strUtf UTF-8 string to be decoded back to Unicode
* @returns {String} decoded string
*/
Utf8.decode = function(strUtf) {
// note: decode 3-byte chars first as decoded 2-byte strings could appear to be 3-byte char!
var strUni = strUtf.replace(
/[\u00e0-\u00ef][\u0080-\u00bf][\u0080-\u00bf]/g, // 3-byte chars
function(c) { // (note parentheses for precence)
var cc = ((c.charCodeAt(0)&0x0f)<<12) | ((c.charCodeAt(1)&0x3f)<<6) | ( c.charCodeAt(2)&0x3f);
return String.fromCharCode(cc); }
);
strUni = strUni.replace(
/[\u00c0-\u00df][\u0080-\u00bf]/g, // 2-byte chars
function(c) { // (note parentheses for precence)
var cc = (c.charCodeAt(0)&0x1f)<<6 | c.charCodeAt(1)&0x3f;
return String.fromCharCode(cc); }
);
return strUni;
}

function encryptForm(key, form){
var params = form_to_params(form);

if(params.length > 0)
return Aes.Ctr.encrypt(params, key, 128);
return false;
}


function stringToHex (s) {
var r = "0x";
var hexes = new Array ("0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f");
for (var i=0; i<s.length; i++) {r += hexes [s.charCodeAt(i) >> 4] + hexes [s.charCodeAt(i) & 0xf];}
return r;
}

function hexToString (h) {
var r = "";
for (var i= (h.substr(0, 2)=="0x")?2:0; i<h.length; i+=2) {r += String.fromCharCode (parseInt (h.substr (i, 2), 16));}
return r;
}


For the purpose of what I'm doing, it really doesn't mater what format of AES encryption is used, I just need something where they both agree. I'm thinking I have different padding settings between the two, but I'm not entirely sure.

Answer

Currently you are trying to match JavaScript AES CTR mode with Java "AES/ECB/PKCS5Padding" mode - the default for "AES", which won't work. CTR mode is available in Java and can be accessed through "AES/CTR/NoPadding". You will need a (unique, randomized) NONCE per encrypt, which you can set by using IVParameterSpec (using the block size for AES: 16 bytes).

I'm assuming here that you don't want us to walk trough the JavaScript counter mode encryption.

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