How to decrypt with CryptoJs?

[Arya Prakasa]

The go file:

package main

import (
	"fmt"

	openssl "github.com/Luzifer/go-openssl/v4"
)

func main() {
	plaintext := "Hello World!"
	passphrase := "z4yH36a6zerhfE5427ZV"

	o := openssl.New()

	enc, err := o.EncryptBytes(passphrase, []byte(plaintext), openssl.PBKDF2SHA256)
	if err != nil {
		fmt.Printf("An error occurred: %s\n", err)
	}

	fmt.Printf("Encrypted text: %s\n", string(enc)) // U2FsdGVkX1928WeGHGmlUbUOk3+MdJ5gt7ydozSxaP0=
}

The js file:

const CryptoJS = require("crypto-js");

const message = "U2FsdGVkX1928WeGHGmlUbUOk3+MdJ5gt7ydozSxaP0="
const key = "z4yH36a6zerhfE5427ZV"

var decryptedData = CryptoJS.AES.decrypt(message, key).toString(CryptoJS.enc.Utf8))

console.log(decryptedData) // 

https://svelte.dev/repl/ff7fe2b993e847a4b19947761fe257b9?version=3.37.0

[Knut Ahlers]

I'm not sure about the implementation you're using but the original crypto-js did only support MD5 key-derivation for AES encryption while your Go-code is using the openssl.PBKDF2SHA256 key-derivation…

[Arya Prakasa]

I am sorry it was copy paste from the example.
Not sure why I can't decrypt the encrypted data although use the same key-derivation.

package main

import (
	"fmt"

	openssl "github.com/Luzifer/go-openssl/v4"
)

func main() {
	c := "U2FsdGVkX18usncIYQU7zpoOtzU88HRePCuBmhJvNJ4Pz7eM5kLKE9DSl+ZQOUzP"
	plaintext := "Hello World!"
	passphrase := "z4yH36a6zerhfE5427ZV"

	o := openssl.New()

	enc, _ := o.EncryptBytes(passphrase, []byte(plaintext), openssl.PBKDF2MD5)
	dec, _ := o.DecryptBytes(passphrase, []byte(string(enc)), openssl.BytesToKeyMD5)
	cjs, _ := o.DecryptBytes(passphrase, []byte(string(c)), openssl.BytesToKeyMD5)

	fmt.Printf("Encrypted text: %s\n", string(enc)) // U2FsdGVkX18q83+Cwf8qmuTEQyP3VKJcfCgsUE/OtOU=
	fmt.Printf("Decrypted text: %s\n", string(dec)) //
	fmt.Printf("CryptoJS: %s\n", string(cjs)) // Encrypted by crypto-js
}

[Knut Ahlers]

Well, the decrypting of the crypto-js part works fine and decrypting data encrypting with openssl.PBKDF2MD5 can only be decrypted with openssl.PBKDF2MD5, not with openssl.BytesToKeyMD5. You need to use the same key-derivation function for decryption you used for encryption.

So modified your example:

package main

import (
	"fmt"

	openssl "github.com/Luzifer/go-openssl/v4"
)

func main() {
	c := "U2FsdGVkX18usncIYQU7zpoOtzU88HRePCuBmhJvNJ4Pz7eM5kLKE9DSl+ZQOUzP"
	plaintext := "Hello World!"
	passphrase := "z4yH36a6zerhfE5427ZV"

	o := openssl.New()

	enc, _ := o.EncryptBytes(passphrase, []byte(plaintext), openssl.BytesToKeyMD5) // <<< See this changed
	dec, _ := o.DecryptBytes(passphrase, []byte(string(enc)), openssl.BytesToKeyMD5)
	cjs, _ := o.DecryptBytes(passphrase, []byte(string(c)), openssl.BytesToKeyMD5)

	fmt.Printf("Encrypted text: %s\n", string(enc)) // U2FsdGVkX18q83+Cwf8qmuTEQyP3VKJcfCgsUE/OtOU=
	fmt.Printf("Decrypted text: %s\n", string(dec)) //
	fmt.Printf("CryptoJS: %s\n", string(cjs))       // Encrypted by crypto-js
}

[Arya Prakasa]

Thanks for your awesome work