decipher.final()：不支持的状态或无法验证数据

Question

我有以下代码：

const crypto = require("crypto");

const algorithm = "aes-256-gcm"; 
const message = "This is a secret message";
const iv = crypto.randomBytes(12);
const sKey = crypto.randomBytes(32);

const cipher = crypto.createCipheriv(algorithm, sKey, iv);
const decipher = crypto.createDecipheriv(algorithm, sKey, iv)

let encryptedData = cipher.update(message, "utf-8", "hex");
encryptedData += cipher.final("hex");

let decData = decipher.update(encryptedData, "hex", "utf-8");
decData += decipher.final("utf-8");

console.log("Encrypted message: " + encryptedData);
console.log("Decrypted message: ", decData)

当我运行它时，我收到以下异常：

node:internal/crypto/cipher:193
  const ret = this[kHandle].final();
                            ^

Error: Unsupported state or unable to authenticate data
    at Decipheriv.final (node:internal/crypto/cipher:193:29)
    at Object.<anonymous> ([...]/crypto-test.js:15:21)
    at Module._compile (node:internal/modules/cjs/loader:1101:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1153:10)
    at Module.load (node:internal/modules/cjs/loader:981:32)
    at Function.Module._load (node:internal/modules/cjs/loader:822:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
    at node:internal/main/run_main_module:17:47

调用decipher.final()时抛出错误。我该如何修复它？

Answer 1

当使用经过身份验证的密码（即 aes-256-gcm）时，您将需要密码中的 auth 标签；否则 Decipher.final() 将抛出（如您所见），因为它具有（或在本例中没有）的身份验证标记与它认为解密文本的身份验证标记不匹配。

const crypto = require('crypto');

const algorithm = 'aes-256-gcm';
const message = 'This is a secret message';
const iv = crypto.randomBytes(12);
const sKey = crypto.randomBytes(32);

const cipher = crypto.createCipheriv(algorithm, sKey, iv);

let encryptedData = cipher.update(message, 'utf-8', 'hex');
encryptedData += cipher.final('hex');

const authTag = cipher.getAuthTag().toString("hex");  // <- new
console.log({authTag, encryptedData});  // for debugging

const decipher = crypto.createDecipheriv(algorithm, sKey, iv);
decipher.setAuthTag(Buffer.from(authTag, 'hex'));  // <- new
let decData = decipher.update(encryptedData, 'hex', 'utf-8');
decData += decipher.final('utf-8');
console.log('Decrypted message: ', decData)