php aes-256-cbc 转 node 加密实现

朋友之前遇到一个问题 ，找到我。 他在对接一个服务，api文档给的示例是php的，如下：

function decrypt($crypt, $key, $type, $iv = "0123456789abcdef") {
  $crypt = base64_decode($crypt);
  $padtext = openssl_decrypt($crypt, "AES-256-CBC", base64_decode($key), OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $iv);
  $pad = ord($padtext [strlen($padtext) - 1]);
  if ($pad > strlen($padtext)) { return false;}
  if (strspn($padtext, $padtext[strlen($padtext) - 1], strlen($padtext) - $pad) != $pad) {
    $text = "Error";
  }
}

Default key: 9v6ZyFBzNYoP2Un8H5cZq5FeBwxL6itqNZsm7lisGBQ=

正常来说 我们使用node 实现如下

const crypto = require('crypto');
const algorithm = 'aes-256-cbc';
const keyStr = '9v6ZyFBzNYoP2Un8H5cZq5FeBwxL6itqNZsm7lisGBQ='
const ivStr = keyStr.substr(0, 16)
const keyByte = Buffer.from(keyStr)
const ivByte = Buffer.from(ivStr)

function encrypt(text) {
    let cipher = crypto.createCipheriv(algorithm, Buffer.from(keyStr), ivByte);
    let encrypted = cipher.update(text);
    encrypted = Buffer.concat([encrypted, cipher.final()]);
    return {
        keyStr: keyStr,
        ivStr: ivByte.toString('hex'),
        encryptedData: encrypted.toString('hex'),
        rawBuffer: encrypted,
        base64Str: encrypted.toString("base64")
    };
}

但运行后发现报错 Invalid key length 查了一些资料 发现 aes-256-cbc 的key长度应该是32位的，他们给的默认key 是44位的，当然，如果你看的多了，自然会发现这个应该是base64加密后的。尝试先解密，发现是乱码。 然后考虑会不会是编码导致的乱码，于是尝试把node 所有的编码都试了下

const base64 = keyStr;

// create a buffer
const buff = Buffer.from(base64, 'base64');


let banma="'ascii'| 'utf8' | 'utf-8' | 'utf16le' | 'ucs2' | 'ucs-2' | 'base64' | 'base64url' | 'latin1' | 'binary' | 'hex'"
const arr=banma.replace(/'/g,'').replace(/ /g,'').split('|')
console.log(arr)
arr.forEach(item=>{
  const str = buff.toString(item);
  console.log(str,item,str.length)
  console.log('-----------------------')
})

输出的还全是乱码

v~HPs5
YI|+^
     Kj+j5X, ascii 32
-----------------------
����Ps5��I����^
               K�+j5�&�X� utf8 32
-----------------------
����Ps5��I����^
               K�+j5�&�X� utf-8 32
-----------------------
ﻶ좙獐訵�ﱉ霟꬙庑ఇ樫鬵걘ᐘ utf16le 16
-----------------------
ﻶ좙獐訵�ﱉ霟꬙庑ఇ樫鬵걘ᐘ ucs2 16
-----------------------
ﻶ좙獐訵�ﱉ霟꬙庑ఇ樫鬵걘ᐘ ucs-2 16
-----------------------
9v6ZyFBzNYoP2Un8H5cZq5FeBwxL6itqNZsm7lisGBQ= base64 44
-----------------------
9v6ZyFBzNYoP2Un8H5cZq5FeBwxL6itqNZsm7lisGBQ base64url 43
-----------------------
öþÈPs5ÙIü«^
           Kê+j5X¬ latin1 32
-----------------------
öþÈPs5ÙIü«^
           Kê+j5X¬ binary 32
-----------------------
f6fe99c85073358a0fd949fc1f9719ab915e070c4bea2b6a359b26ee58ac1814 hex 64

后来灵机一动，反正都是buffer了 ，为什么还要去考虑解密key 于是使用 Buffer.from(keyStr,'base64') 试了一下 成功了。

let cipher = crypto.createCipheriv(algorithm, Buffer.from(keyStr,'base64'), ivByte);

完整代码如下

// Nodejs encryption with CTR
const { atob } = require('buffer');
const crypto = require('crypto');
const algorithm = 'aes-256-cbc';
const keyStr = '9v6ZyFBzNYoP2Un8H5cZq5FeBwxL6itqNZsm7lisGBQ='
const ivStr = keyStr.substr(0, 16)
const keyByte = Buffer.from(keyStr)
const ivByte = Buffer.from(ivStr)


function encrypt(text) {
    let cipher = crypto.createCipheriv(algorithm, Buffer.from(keyStr,'base64'), ivByte);
    let encrypted = cipher.update(text);
    encrypted = Buffer.concat([encrypted, cipher.final()]);
    return {
        keyStr: keyStr,
        ivStr: ivByte.toString('hex'),
        encryptedData: encrypted.toString('hex'),
        rawBuffer: encrypted,
        base64Str: encrypted.toString("base64")
    };
}

function decrypt(text) {
    let encryptedData = text.encryptedData
    let iv = Buffer.from(text.ivStr, 'hex');
    let encryptedText = Buffer.from(encryptedData, 'hex');
    let decipher = crypto.createDecipheriv(algorithm, Buffer.from(keyStr,'base64'), iv);
    let decrypted = decipher.update(encryptedText);
    decrypted = Buffer.concat([decrypted, decipher.final()]);
    return decrypted.toString();
}


function decryptBase64(base64Str, ivStr) {
    let buff = Buffer.from(base64Str, 'base64')
    let encryptedData = buff.toString('hex')

    let iv = Buffer.from(ivStr, 'hex');
    let encryptedText = Buffer.from(encryptedData, 'hex');
    let decipher = crypto.createDecipheriv(algorithm, Buffer.from(keyStr), iv);
    let decrypted = decipher.update(encryptedText);
    decrypted = Buffer.concat([decrypted, decipher.final()]);
    return decrypted.toString();
}


var hw = encrypt("001002003004005006007+（）")
console.log('encrypted = ', hw)
console.log('decode = ', decrypt(hw))
console.log('decode2 = ', decryptBase64(keyStr,ivStr))