CODEWITHSUNDEEP
goencryption
Nilay Singh
Nilay Singh

Reputation: 2331

Cross Platform AES CryptLib

I am trying to convert the logic of Crypt Lib in js I have existing android application and the API is in c sharp and I want to convert encrypt and decrypt logic.

I have tried multiple variations you can check the code: Tried code

I have a sample data which I want to decrypt and the data is:

{"Data":"bvtkHfZiTsY0CX6QmHhCboBwXeY9RZVPpdhhdIy6aSwCTVI7YiEGha1aXTIKY4BocGdNIbWkreQHZcTk4WE6F2tQLoVyWERYCGZotbDzxxs=","IV":"Vmr-uU5mA2_Zr_13"}

Here I have the encrypted data in Data and IV so when I am trying to decrypt this data I can't find any solution. All the encrypt and decrypt function is in csharp and android code. But I want to convert the same logic in golang.

The logic in Node

I have tried this code:

    iv := []byte("Vmr-uU5mA2_Zr_13")
    key := []byte("<Secret_Key")

    text := []byte("bvtkHfZiTsY0CX6QmHhCboBwXeY9RZVPpdhhdIy6aSwCTVI7YiEGha1aXTIKY4BocGdNIbWkreQHZcTk4WE6F2tQLoVyWERYCGZotbDzxxs=")

    cipherBlock, err := aes.NewCipher(key)
    if err != nil {
        log.Fatal(err)
    }

    cipher.NewCBCDecrypter(cipherBlock, iv).CryptBlocks(text, text)
    fmt.Println(string(text))

Full link to the code and I am getting error:

crypto/aes: invalid key size 64

Upvotes: 1

Views: 574

Answers (1)

Jem Tucker
Jem Tucker

Reputation: 1163

It looks like you need to decode your key and text strings properly into byte slices, not just cast them. The code below works, although I am not sure what the decoded message should look like...

package main

import (
    "encoding/hex"
    "encoding/base64"
    "crypto/cipher"
    "crypto/sha256"
    "crypto/aes"
)

func main() {
    iv := "Vmr-uU5mA2_Zr_13"
    key := "<Secret_Key>"
    ciphertext := "bvtkHfZiTsY0CX6QmHhCboBwXeY9RZVPpdhhdIy6aSwCTVI7YiEGha1aXTIKY4BocGdNIbWkreQHZcTk4WE6F2tQLoVyWERYCGZotbDzxxs="
    
    hash := sha256.Sum256([]byte(key))
    key = hex.EncodeToString(hash[:])[:32]
    
    btext, err := base64.StdEncoding.DecodeString(ciphertext)
    if err != nil {
        println("Error decoding cipertext: ", err.Error())
        return
    }

    aesCipher, err := aes.NewCipher([]byte(key))
    if err != nil {
        println("Error creating cipher: ", err.Error())
        return
    }

    cipher.NewCBCDecrypter(aesCipher, []byte(iv)).
        CryptBlocks(btext, btext)
    
    println("Result: ", string(btext))
}

Upvotes: 2

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