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Decrypt AES in JavaScript

I am encrypting a text with AES256 in swift language and outputting it as hex. I want to decrypt this code I received with JS, but I could not reach the result. I tried the CryptoJS library but still couldn't get the result I wanted. All I want is the js code that will give me the decoded version when I enter the IV, password and ciphertext.
const crypto = require("crypto");
var key = "";
const iv = "";
const token = "";
function decrypt(token, iv, key) {
const decrypter = crypto.createDecipheriv("aes-256-cbc", key, iv);
let decrypted = decrypter.update(token, "hex", "utf8");
decrypted += decrypter.final("utf8");
return decrypted
}
console.log(decrypt(token, iv, key));
With the Node.js code above, I achieve what I want, but I want to do it with normal JS code, not using node. I don't want to mess with the server. I would be very happy if you help.
EDIT:
I am using CryptoSwift library in Swift language.
func encryption(uuid: String, token: String) -> String {
do {
let aes = try AES(key: String(uuid.prefix(32)), iv: String(uuid.prefix(16)))
let ciphertext = try aes.encrypt(Array(token.utf8))
let encrypttext = ciphertext.toHexString()
return encrypttext
}
catch {
return "error"
}
}
I tried to do something with CryptoJS with the codes from the site below, but it didn't work like the codes in Node.js.
https://embed.plnkr.co/0VPU1zmmWC5wmTKPKnhg/
EDIT2:
I've been trying different things but couldn't quite figure it out. I get an error when I add PBKDF2. I don't fully understand the problem.
var password = "6268890F-9B58-484C-8CDC-34F9C6A9";
var iv = "6268890F-9B58-48";
var cipher = "79a247e48ac27ed33ca3f1919067fa64";
/*
var key = CryptoJS.PBKDF2(password, {
keySize: 32
});
*/
var dec= CryptoJS.enc.Hex.parse(cipher);
const decrypted = CryptoJS.AES.decrypt({
ciphertext: dec
},
password, {
iv: iv,
mode: CryptoJS.mode.CBC,
padding: CryptoJS.pad.Pkcs7
});
console.log(decrypted.toString(CryptoJS.enc.Utf8));
<script src="https://cdnjs.cloudflare.com/ajax/libs/crypto-js/3.1.2/rollups/aes.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/crypto-js/3.1.2/rollups/pbkdf2.js"></script>

CryptoJS uses WordArrays, so that key, IV and ciphertext have to be converted accordingly. For this purpose the appropriate encoders have to be applied. Furthermore decrypt() expects the ciphertext as CipherParams object.
This results in the following possible CryptoJS implementation:
var ciphertext = "79a247e48ac27ed33ca3f1919067fa64";
var key = "6268890F-9B58-484C-8CDC-34F9C6A9";
var iv = "6268890F-9B58-48";
var ciphertextWA = CryptoJS.enc.Hex.parse(ciphertext);
var keyWA = CryptoJS.enc.Utf8.parse(key);
var ivWA = CryptoJS.enc.Utf8.parse(iv);
var ciphertextCP = { ciphertext: ciphertextWA };
var decrypted = CryptoJS.AES.decrypt(
ciphertextCP,
keyWA,
{ iv: ivWA }
);
console.log(decrypted.toString(CryptoJS.enc.Utf8)); // Apple
<script src="https://cdnjs.cloudflare.com/ajax/libs/crypto-js/4.0.0/crypto-js.min.js"></script>
which is functionally identical to the posted NodeJS code that also successfully decrypts the test data.
Regarding the question asked in the comment about the encodings:
In general, the decryption side must have knowledge of the encodings used for encryption. However, in this case the encodings can be derived from the posted NodeJS code:
For decryption, the input encoding of the ciphertext is specified as 'hex', see decipher.update().
key and iv are defined as strings which are UTF-8 encoded, see crypto.createDecipheriv().
Also, the data used is consistent with these conclusions.
Note that for security reasons a static IV may not be used. Instead, a random IV must be generated for each encryption.
Also, no password may be applied as key, even if it has the right length. If a password is to be used, a key derivation is necessary, e.g. with PBKDF2.
For test purposes, the data is of course enough.

Python bytestring => Javascript?

I'm attempting to port some Python code to Javascript. Here is the Python code:
# Python
import codecs
from Crypto.Cipher import AES
key = b"\xc3\x99\xff\xff\xc3\x99\xff\xff\xc3\x99\xff\xff\xc3\x99\xff\xff"
...
aes = AES.new(key, AES.MODE_ECB)
token = aes.encrypt("HELLO\x00\x00".encode("utf-8"))
token_hex = codecs.encode(token, "hex").decode("utf-8")
I'm not exactly sure how to port my Python key variable. Should it be UInt16Array...or a string?
This is my Javascript so far:
// Javascript
const crypto = require('crypto');
const key = '???' // <-- This is one place I am stuck. String? Byte array?
....
const cipher = crypto.createCipher('aes-128-ecb', key);
let tokenHex = cipher.update('HELLO\x00\x00', 'utf8', 'hex');
tokenHex = tokenHex.toString('utf8')
I appreciate any insight you can provide as to how I can get a matching tokenHex in Javascript.
Thank you!

What you are after is Buffer, which represents a collection of bytes.
You probably want to instantiate the key variable similar to this:
let key = Buffer.from("c399ff...", "hex");

String to UTF8 to SHA256 to BASE64

In C# I have the following code:
public static string GetHashCode(string p)
{
var a = new SHA256Managed();
return Convert.ToBase64String(a.ComputeHash(new System.Text.UTF8Encoding().GetBytes(p)));
}
And I have to achieve the same thing in Javascript, I was trying the following but it gives different result:
btoa((CryptoJS.SHA256(this.toUTF8Array(this.settingsService.Password)).toString(CryptoJS.enc.Hex)));
What am I supposed to do, what is wrong?
Example output for string 'aaa' for:
C#:1f9e1d76685d765aa3a6ff85dced2f0a04f612536df52696684aaa67787e6cdd
Js:NGVhNWM1MDhhNjU2NmU3NjI0MDU0M2Y4ZmViMDZmZDQ1Nzc3N2JlMzk1NDljNDAxNjQzNmFmZGE2NWQyMzMwZQ==

I'm not that familiar with CryptoJS but I think you are outputting hex which is not the same as base64.
This generates the same result as C# see fiddle
var utf8arr = CryptoJS.enc.Utf8.parse("apassword");
var hash = CryptoJS.SHA256(utf8arr);
var base64 = CryptoJS.enc.Base64.stringify(hash);
console.log(base64);

different output for JAVA vs javascript AES 256 cbc

Im trying to create an AES 256 cbc encryption using java and I need to emulate EXACTLY this javascript code (I know the iv is the same as the key (turnicated to 16 bytes), that's how it is from the site i'm trying to log into using java)
var recievedStr = "MDk4NTY1MDAyMjg2MTU1OA=="; //some
var key = CryptoJS.enc.Base64.parse(recievedStr);
var iv = CryptoJS.enc.Base64.parse(recievedStr);
var pw = "PASSWORD";
var encres = CryptoJS.AES.encrypt(pw, key, {iv:iv, keySize: 256, mode: CryptoJS.mode.CBC, padding: CryptoJS.pad.Pkcs7});
var finalStr = encres.toString();
finalStr will be : Su92ZXLm/MdOyruRnWDRqQ==
I need to make a java code that will output exactly the same output as finalStr from the javascript.
Im using bouncy castle for that.
String recievedStr = "MDk4NTY1MDAyMjg2MTU1OA==";
String pw = "PASSWORD";
AESEngine blockCipher = new AESEngine();
CBCBlockCipher cbcCipher = new CBCBlockCipher(blockCipher);
BufferedBlockCipher cipher = new PaddedBufferedBlockCipher (cbcCipher);
byte[] key = encodeBase64(recievedStr);
byte [] iv = java.util.Arrays.copyOf(key,16);
byte[] input = pw.getBytes();
ParametersWithIV pwIV= new ParametersWithIV(new KeyParameter(key),iv);
cipher.init(true, pwIV);
byte[] cipherText = new byte[cipher.getOutputSize(input.length)];
int outputLen = cipher.processBytes(input, 0, input.length, cipherText, 0);
try
{
cipher.doFinal(cipherText, outputLen);
}
catch (CryptoException ce)
{
System.err.println(ce);
}
System.out.println(new String(Base64.encodeBase64(cipherText)));
this will output : qEGQ1PC/QKxfAxGBIbLKpQ==
while I can decrypt it to the original input, that is not what i want.
I need my java code to output exactly what the javascript did.
I have 0 ideas left on how to approach this.
Thanks.
EDIT: problem was solved, I had to decode the received string to base64 instead of encoding it.

I think you are on the right track. But I think you are running with AES-128 instead of AES-256. If you have a look at Java 256-bit AES Password-Based Encryption I think maybe you can find something useful.

Encrypt in python - decrypt in Javascript

I have need to simply encrypt some text in python and being able to decrypt in JavaScrypt.
So far I have in python:
from Crypto import Random
from Crypto.Cipher import AES
import base64
BLOCK_SIZE = 16
key = "1234567890123456" # want to be 16 chars
textToEncrypt = "This is text to encrypt"
def encrypt(message, passphrase):
# passphrase MUST be 16, 24 or 32 bytes long, how can I do that ?
IV = Random.new().read(BLOCK_SIZE)
aes = AES.new(passphrase, AES.MODE_CFB, IV)
return base64.b64encode(aes.encrypt(message))
def decrypt(encrypted, passphrase):
IV = Random.new().read(BLOCK_SIZE)
aes = AES.new(passphrase, AES.MODE_CFB, IV)
return aes.decrypt(base64.b64decode(encrypted))
print encrypt( textToEncrypt, key )
this is producing text: ZF9as5JII5TlqcB5tAd4sxPuBXd5TrgE
in JavaScript:
<script src="http://crypto-js.googlecode.com/svn/tags/3.1.2/build/rollups/aes.js"></script>
<script>
var decrypted = CryptoJS.AES.decrypt( "ZF9as5JII5TlqcB5tAd4sxPuBXd5TrgE", "1234567890123456");
console.log ( decrypted.toString( CryptoJS.enc.Utf8 ) );
</script>
however it does not produce original string (empty string instead).
What I am doing wrong ?
Is it focusing on AES is a best idea - I will be happy if I have some kind of encryption that will blur data.

There are many problems with your Python code and CryptoJS code:
You use a random IV to encrypt some plaintext in Python. If you want to retrieve that plaintext, you need to use the same IV during decryption. The plaintext cannot be recovered without the IV. Usually the IV is simply prepended to the ciphertext, because it doesn't have to be secret. So you need to read the IV during decryption and not generate a new one.
You use CBC mode in CryptoJS (default) instead of CFB mode. The mode has to be the same. The other tricky part is that CFB mode is parametrized with a segment size. PyCrypto uses by default 8-bit segments (CFB8), but CryptoJS is only implemented for fixed segments of 128-bit (CFB128). Since the PyCrypto version is variable, you need to change that.
The CryptoJS decrypt() function expects as ciphertext either an OpenSSL formatted string or a CipherParams object. Since you don't have an OpenSSL formatted string, you have to convert the ciphertext into an object.
The key for CryptoJS is expected to be a WordArray and not a string.
Use the same padding. PyCrypto doesn't pad the plaintext if CFB8 is used, but padding is needed when CFB128 is used. CryptoJS uses PKCS#7 padding by default, so you only need to implement that padding in python.
Python code (for version 2):
def pad(data):
length = 16 - (len(data) % 16)
return data + chr(length)*length
def unpad(data):
return data[:-ord(data[-1])]
def encrypt(message, passphrase):
IV = Random.new().read(BLOCK_SIZE)
aes = AES.new(passphrase, AES.MODE_CFB, IV, segment_size=128)
return base64.b64encode(IV + aes.encrypt(pad(message)))
def decrypt(encrypted, passphrase):
encrypted = base64.b64decode(encrypted)
IV = encrypted[:BLOCK_SIZE]
aes = AES.new(passphrase, AES.MODE_CFB, IV, segment_size=128)
return unpad(aes.decrypt(encrypted[BLOCK_SIZE:]))
JavaScript code:
<script src="https://cdn.rawgit.com/CryptoStore/crypto-js/3.1.2/build/rollups/aes.js"></script>
<script src="https://cdn.rawgit.com/CryptoStore/crypto-js/3.1.2/build/components/mode-cfb-min.js"></script>
<script>
var base64ciphertextFromPython = "...";
var ciphertext = CryptoJS.enc.Base64.parse(base64ciphertextFromPython);
// split iv and ciphertext
var iv = ciphertext.clone();
iv.sigBytes = 16;
iv.clamp();
ciphertext.words.splice(0, 4); // delete 4 words = 16 bytes
ciphertext.sigBytes -= 16;
var key = CryptoJS.enc.Utf8.parse("1234567890123456");
// decryption
var decrypted = CryptoJS.AES.decrypt({ciphertext: ciphertext}, key, {
iv: iv,
mode: CryptoJS.mode.CFB
});
console.log ( decrypted.toString(CryptoJS.enc.Utf8));
</script>
Other considerations:
It seems that you want to use a passphrase as a key. Passphrases are usually human readable, but keys are not. You can derive a key from a passphrase with functions such as PBKDF2, bcrypt or scrypt.
The code above is not fully secure, because it lacks authentication. Unauthenticated ciphertexts may lead to viable attacks and unnoticed data manipulation. Usually the an encrypt-then-MAC scheme is employed with a good MAC function such as HMAC-SHA256.

(1 Year later but I hope this works for someone)
First of all, thanks Artjom B. your post helps me a lot. And Like OP, I have the same same problem Python server endonding and Javascript client decoding. This was my solution:
Python 3.x (Server)
I used an excplicit PKCS7 encode for padding, why? because I want to be sure Im using the same padding enconding and decoding, this is the link where I found it http://programmerin.blogspot.com.co/2011/08/python-padding-with-pkcs7.html .
Then, like Artjom B. said, be sure about your segment size, IV size and AES mode (CBC for me),
This is the code:
def encrypt_val(clear_text):
master_key = '1234567890123456'
encoder = PKCS7Encoder()
raw = encoder.encode(clear_text)
iv = Random.new().read( 16 )
cipher = AES.new( master_key, AES.MODE_CBC, iv, segment_size=128 )
return base64.b64encode( iv + cipher.encrypt( raw ) )
Note than your are enconding on base64 the concatenation of IV and encryption data.
Javascript (client)
function decryptMsg (data) {
master_key = '1234567890123456';
// Decode the base64 data so we can separate iv and crypt text.
var rawData = atob(data);
// Split by 16 because my IV size
var iv = rawData.substring(0, 16);
var crypttext = rawData.substring(16);
//Parsers
crypttext = CryptoJS.enc.Latin1.parse(crypttext);
iv = CryptoJS.enc.Latin1.parse(iv);
key = CryptoJS.enc.Utf8.parse(master_key);
// Decrypt
var plaintextArray = CryptoJS.AES.decrypt(
{ ciphertext: crypttext},
key,
{iv: iv, mode: CryptoJS.mode.CBC, padding: CryptoJS.pad.Pkcs7}
);
// Can be Utf8 too
output_plaintext = CryptoJS.enc.Latin1.stringify(plaintextArray);
console.log("plain text : " + output_plaintext);
}
One of my main problem was keep in mind all kind of encoding and decoding data, for example, I didn't know that the master_key on client side was to be parse with Utf8.

//First pip install pycryptodome -- (pycrypto is obsolete and gives issues)
// pip install pkcs7
from Crypto import Random
from Crypto.Cipher import AES
import base64
from pkcs7 import PKCS7Encoder
from app_settings.views import retrieve_settings # my custom settings
app_secrets = retrieve_settings(file_name='secrets');
def encrypt_data(text_data):
#limit to 16 bytes because my encryption key was too long
#yours could just be 'abcdefghwhatever'
encryption_key = app_secrets['ENCRYPTION_KEY'][:16];
#convert to bytes. same as bytes(encryption_key, 'utf-8')
encryption_key = str.encode(encryption_key);
#pad
encoder = PKCS7Encoder();
raw = encoder.encode(text_data) # Padding
iv = Random.new().read(AES.block_size ) #AES.block_size defaults to 16
# no need to set segment_size=BLAH
cipher = AES.new( encryption_key, AES.MODE_CBC, iv )
encrypted_text = base64.b64encode( iv + cipher.encrypt( str.encode(raw) ) )
return encrypted_text;