CODEWITHSUNDEEP
node.jsgoencryption
J Del
J Del

Reputation: 881

Golang Decrypt AES 256 CBC base64 from NodeJS

This is what I have in Node.js:

var crypto = require('crypto')

function encryptstring(str) {
    var cipher = crypto.createCipheriv('aes-256-cbc', 'NFd6N3v1nbL47FK0xpZjxZ7NY4fYpNYd', 'TestingIV1234567'),
        encrypted = cipher.update(str, 'utf-8', 'base64');
    encrypted += cipher.final('base64');
    return encrypted;
}

console.log(encryptstring("Testing 111111111111111111111111111111111111111111"))

That returns: w2f0vBP2hRfgVqssqOluk68Qxkc9LXFESc0ZGzPBq3p6f/x/LbwBbg1XOoRr7I/DAtESJGdweKG6nL9m8RfewA==

This is what I have in Go:

package main

import (
    "crypto/aes"
    "crypto/cipher"
    "encoding/base64"
    "fmt"
)

// decrypt from base64 to decrypted string
func decrypt(key []byte, iv []byte, cryptoText string) string {
    ciphertext, _ := base64.URLEncoding.DecodeString(cryptoText)
    block, err := aes.NewCipher(key)
    if err != nil {
        panic(err)
    }
    if len(ciphertext) < aes.BlockSize {
        panic("ciphertext too short")
    }

    ciphertext = ciphertext[aes.BlockSize:]
    stream := cipher.NewCFBDecrypter(block, iv)
    stream.XORKeyStream(ciphertext, ciphertext)

    return fmt.Sprintf("%s", ciphertext)
}

func main() {
    encKey := "NFd6N3v1nbL47FK0xpZjxZ7NY4fYpNYd"
    iv := "TestingIV1234567"
    stringtodecrypt := "w2f0vBP2hRfgVqssqOluk68Qxkc9LXFESc0ZGzPBq3p6f/x/LbwBbg1XOoRr7I/DAtESJGdweKG6nL9m8RfewA=="

    stringtodecrypt = decrypt([]byte(encKey), []byte(iv), stringtodecrypt)

    fmt.Println(string(stringtodecrypt))
}

That ends up returning _▒▒▒6▒▒d,O▒ob"▒

A lot of the Go code was taken from https://gist.github.com/manishtpatel/8222606

I tried this as well: How do I decrypt an AES256 bit cipher in golang that was encrypted in nodejs? (with some modifications as hex.DecodeString was not necessary in this case) but it would throw an error saying panic: crypto/cipher: input not full blocks

This was my code when I tried that:

func main() {
    encKey := "NFd6N3v1nbL47FK0xpZjxZ7NY4fYpNYd"
    iv := "TestingIV1234567"
    stringtodecrypt := "w2f0vBP2hRfgVqssqOluk68Qxkc9LXFESc0ZGzPBq3p6f/x/LbwBbg1XOoRr7I/DAtESJGdweKG6nL9m8RfewA=="

    block, err := aes.NewCipher([]byte(encKey))
    if err != nil {
        panic(err)
    }

    mode := cipher.NewCBCDecrypter(block, []byte(iv))

    mode.CryptBlocks([]byte(stringtodecrypt), []byte(stringtodecrypt))

    fmt.Println(string(stringtodecrypt))
}

I've searched around a lot and I can't seem to figure this out.

What am I doing wrong?

Upvotes: 3

Views: 5586

Answers (1)

JimB
JimB

Reputation: 109308

Your second attempt was closer, but you didn't decode the base64 string first.

If you go by the CBCDecrypter example in the cipher package, you would have something like this:

encKey := "NFd6N3v1nbL47FK0xpZjxZ7NY4fYpNYd"
iv := "TestingIV1234567"
ciphertext, err := base64.StdEncoding.DecodeString("w2f0vBP2hRfgVqssqOluk68Qxkc9LXFESc0ZGzPBq3p6f/x/LbwBbg1XOoRr7I/DAtESJGdweKG6nL9m8RfewA==")
if err != nil {
    panic(err)
}

block, err := aes.NewCipher([]byte(encKey))
if err != nil {
    panic(err)
}

if len(ciphertext)%aes.BlockSize != 0 {
    panic("ciphertext is not a multiple of the block size")
}

mode := cipher.NewCBCDecrypter(block, []byte(iv))
mode.CryptBlocks(ciphertext, ciphertext)

fmt.Printf("%s\n", ciphertext)

https://play.golang.org/p/16wV2UJ5Iw

Upvotes: 6

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