EVP_DecryptFinal_ex:使用Node.js时解密不正确 [英] EVP_DecryptFinal_ex:bad decrypt when using Node.js

问题描述

使用以下节点js:

var crypto = require('crypto');
var encrypt = function (input, password, callback) {
    var m = crypto.createHash('md5');
    m.update(password);
    var key = m.digest('hex');

    m = crypto.createHash('md5');
    m.update(password + key);
    var iv = m.digest('hex');
    console.log(iv);

    var data = new Buffer(input, 'utf8').toString('binary');

    var cipher = crypto.createCipheriv('aes-256-cbc', key, iv.slice(0,16));
    var encrypted = cipher.update(data, 'binary') + cipher.final('binary');
    var encoded = new Buffer(encrypted, 'binary').toString('base64');
    callback(encoded);
};

var decrypt = function (input, password, callback) {
    // Convert urlsafe base64 to normal base64
    input = input.replace(/\-/g, '+').replace(/_/g, '/');
    // Convert from base64 to binary string
    var edata = new Buffer(input, 'base64').toString('binary');

    // Create key from password
    var m = crypto.createHash('md5');
    m.update(password);
    var key = m.digest('hex');

    // Create iv from password and key
    m = crypto.createHash('md5');
    m.update(password + key);
    var iv = m.digest('hex');

    // Decipher encrypted data
    var decipher = crypto.createDecipheriv('aes-256-cbc', key, iv.slice(0,16));
    var decrypted = decipher.update(edata, 'binary') + decipher.final('binary');
    var plaintext = new Buffer(decrypted, 'binary').toString('utf8');

    callback(plaintext);
};

要执行，我运行了此

encrypt("uWeShxRrCKyK4pcs", "secret", function (encoded) {
    console.log(encoded);
    decrypt(encoded, "secret", function (output) {
        console.log(output);
    });
});

加密似乎可以正常工作，但是当我尝试解密时，出现以下错误:

Encrypting seems to work fine, but when I try to decrypt, I receive the following error:

错误:错误:06065064:数字信封 例程:EVP_DecryptFinal_ex:错误解密 错误时(本机) 在Decipheriv.Cipher.final(crypto.js:202:26)

Error: error:06065064:digital envelope routines:EVP_DecryptFinal_ex:bad decrypt at Error (native) at Decipheriv.Cipher.final (crypto.js:202:26)

我对密码学还很陌生，所以真的不知道为什么会收到此错误.我现在只需要修复它.

I am pretty new to cryptography, so don't really know why I am receiving this error. I just need to get it fixed for now.

推荐答案

您混合了两种不同的编码.见

You mixed up two different encodings. See

cipher.update(data[, input_encoding][, output_encoding])

和

cipher.final([output_encoding])

现在看看

var encrypted = cipher.update(data, 'binary') + cipher.final('binary');

但应该是

var encrypted = cipher.update(data, 'binary', 'binary') + cipher.final('binary');

问题是cipher.update(data, 'binary')输出的缓冲区会自动字符串化为十六进制编码的字符串，而不是二进制"字符串.

The issue is that cipher.update(data, 'binary') outputs a buffer which automatically stringifies to a Hex-encoded string instead of a "binary"-string.

无论如何，此代码有太多错误，您应该重新开始并仅使用经过高度评价的现有库.

Anyway, there is so much wrong with this code that you should start over and simply use an existing library that is highly opinionated.

• 您必须必须有一个随机IV，该IV会放在密文之前，以达到语义安全性.

• You must have a random IV which is prepended to the ciphertext in order to reach semantic security.

密码的熵低，不能用作密钥.一次MD5调用不会改变这一事实.假定从密码派生密钥的速度很慢，所以请使用已知的方案，例如PBKDF2，bcrypt，scrypt或Argon2(提高安全性)，并具有较高的迭代计数/成本因子.不要忘记盐.

A password has low entropy and cannot be used as a key. A single MD5 invocation doesn't change that fact. Key derivation from a password is supposed to be slow, so use a known scheme such as PBKDF2, bcrypt, scrypt or Argon2 (increasing security) with a high iteration count/cost factor. Don't forget the salt.

使用加密-然后-MAC方案中的消息认证代码(例如HMAC-SHA256)对密文进行认证.否则，攻击者可能会操纵密文，您甚至将无法检测到更改.通过填充Oracle攻击来丢失数据的第一步.

Authenticate your ciphertext with a message authentication code such as HMAC-SHA256 in an encrypt-then-MAC scheme. Otherwise, an attacker may manipulate ciphertexts and you won't even be able to detect changes. First step to losing data with a padding oracle attack.

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