Overview

const crypto = require('crypto');

function decryptStringAES(cipherText, clientId) {
    const iv = Buffer.from(clientId.slice(0, 16), 'utf8');
    const key = Buffer.from(clientId.slice(-16), 'utf8');
    const encrypted = Buffer.from(cipherText, 'base64');
    try {
        const decipher = crypto.createDecipheriv('aes-128-cbc', key, iv);
        let decrypted = decipher.update(encrypted);
        decrypted = Buffer.concat([decrypted, decipher.final()]);
        return JSON.parse(decrypted.toString());
    } catch (err) {
        return "keyError";
    }
}

type CardInformation struct {
	CardNumber string `json:"card_number"`
	CardCvv    string `json:"cvv"`
	CardExpiry string `json:"expiry"`
	MaskedPan  string `json:"masked_pan"`
}


func decryptCardInformation(clientId, cipherText string) CardInformation {

	iv := []byte(clientId[:16])
	key := []byte(clientId[len(clientId)-16:])
	encrypted, _ := base64.StdEncoding.DecodeString(cipherText)

	block, err := aes.NewCipher(key)
	if err != nil {
		panic(err)
	}

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

	mode := cipher.NewCBCDecrypter(block, iv)
	decrypted := make([]byte, len(encrypted))
	mode.CryptBlocks(decrypted, encrypted)

	// remove PKCS7 padding
	padLen := int(decrypted[len(decrypted)-1])
	decrypted = decrypted[:len(decrypted)-padLen]

	var details CardInformation
	err = json.Unmarshal([]byte(decrypted), &details)
	if err != nil {
		panic(err)
	}

	return details
}

function decryptStringAES($cipherText, $clientId) {
    $iv = substr($clientId, 0, 16);
    $key = substr($clientId, -16);
    $cipherBytes = base64_decode($cipherText);
    $decrypted = openssl_decrypt($cipherBytes, 'AES-128-CBC', $key, OPENSSL_RAW_DATA, $iv);
    if ($decrypted === false) {
        return "keyError";
    }
    return json_decode($decrypted, true);
}