Node.JS encrypt using MD5 / ECB and padding w/PKCS7

Question

I inherited a database that has the passwords utilizing the following functions to encrypt/decrypt in VB.NET

Public Shared Function EncryptString(ByVal Message As String, ByVal Passphrase As String) As String
        Dim Results As Byte()
        Dim UTF8 As System.Text.UTF8Encoding = New System.Text.UTF8Encoding()
        Dim HashProvider As MD5CryptoServiceProvider = New MD5CryptoServiceProvider()
        Dim TDESKey As Byte() = HashProvider.ComputeHash(UTF8.GetBytes(Passphrase))
        Dim TDESAlgorithm As TripleDESCryptoServiceProvider = New TripleDESCryptoServiceProvider()
        TDESAlgorithm.Key = TDESKey
        TDESAlgorithm.Mode = CipherMode.ECB
        TDESAlgorithm.Padding = PaddingMode.PKCS7
        Dim DataToEncrypt As Byte() = UTF8.GetBytes(Message)
        Dim Encryptor As ICryptoTransform = TDESAlgorithm.CreateEncryptor()
        Results = Encryptor.TransformFinalBlock(DataToEncrypt, 0, DataToEncrypt.Length)
        Return Convert.ToBase64String(Results)
    End Function


    Public Shared Function DecryptString(ByVal Message As String, ByVal Passphrase As String) As String
        Dim Results As Byte()
        Dim UTF8 As System.Text.UTF8Encoding = New System.Text.UTF8Encoding()
        Dim HashProvider As MD5CryptoServiceProvider = New MD5CryptoServiceProvider()
        Dim TDESKey As Byte() = HashProvider.ComputeHash(UTF8.GetBytes(Passphrase))
        Dim TDESAlgorithm As TripleDESCryptoServiceProvider = New TripleDESCryptoServiceProvider()
        TDESAlgorithm.Key = TDESKey
        TDESAlgorithm.Mode = CipherMode.ECB
        TDESAlgorithm.Padding = PaddingMode.PKCS7
        Dim DataToDecrypt As Byte() = Convert.FromBase64String(Message)
        Dim Decryptor As ICryptoTransform = TDESAlgorithm.CreateDecryptor()
        Results = Decryptor.TransformFinalBlock(DataToDecrypt, 0, DataToDecrypt.Length)
        Return UTF8.GetString(Results)
    End Function

I am having a hard time encrypting the data to query the SQL server.

When using EncryptString with the following parameters:

Message = stack-overflow

Passphrase = Danielle

I get:

1c2wL+guV34oyVS0vkxwVA==

I need to do this encryption and decryption with node.js

I tried this but it did not work:

var crypto = require('crypto');



encrypt(text, paraphrase) {
        const key =text;
        const secret =paraphrase;

        // Encryption
        const cipher = crypto.createCipheriv("aes-192-ecb", Buffer.from(key, "base64"), null);
        const encryptedSecret = cipher.update(secret, "utf8", "base64") + cipher.final("base64");
        return(encryptedSecret);

    
    };

I also tried installing MD5 by npm but I had no luck either.

Any help to encrypt and decrypt will be appreciated. Thank you all.

user_9014097 · Answer

For the NodeJS code to be compatible with the VB code, TripleDES must be used instead of AES. The key must be derived with MD5. Since MD5 provides a 16 bytes key, TripleDES is applied in the double-length key variant (2TDEA), which combines two DES keys K1 and K2 to a TripleDES key K1|K2|K1. One possible implementation is:

var key16 = crypto.createHash('md5').update(passphrase).digest();
var cipher = crypto.createCipheriv("des-ede-ecb", key16, null);
var ciphertext = cipher.update(data, "utf8", "base64") + cipher.final("base64");

If des-ede-ecb is not supported, des-ede3-ecb can be used as an alternative. This implements TripleDES in the triple-length key variant (3TDEA), which combines three DES keys K1, K2 and K3 to a TripleDES key K1|K2|K3. For K3 = K1 this is equivalent to 2TDEA:

var key16 = crypto.createHash('md5').update(passphrase).digest();
var key24 = Buffer.concat([key16, key16.slice(0, 8)]);
var cipher = crypto.createCipheriv("des-ede3-ecb", key24, null);

Note that ECB is insecure (better a mode with an IV like GCM), as is key derivation via a cryptographic hash function (better a reliable key derivation function like PBKDF2) and the broken MD5 as such (better SHA256). TripleDES is deprecated and slow (better AES).

Edit:

The decryption is completely analog, e.g. for 2TDEA:

var key16 = crypto.createHash('md5').update(passphrase).digest();
var decipher = crypto.createDecipheriv("des-ede-ecb", key16, null);
var decrypted = decipher.update(ciphertext, "base64", "utf8") + decipher.final("utf8");

Node.JS encrypt using MD5 / ECB and padding w/PKCS7

1 Answers

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