TripleDES解密问题

Question

我使用Visual Basic中的以下函数用3des对字符串"Test“进行了解码：

Imports System.IO
Imports System.Text
Imports System.Security.Cryptography

Friend Class cTripleDES

    ' define the triple des provider
    Private m_des As New TripleDESCryptoServiceProvider

    ' define the string handler
    Private m_utf8 As New ASCIIEncoding

    ' define the local property arrays
    Private m_key() As Byte
    Private m_iv() As Byte

    Public Sub New(ByVal key() As Byte, ByVal iv() As Byte)
        Me.m_key = key
        Me.m_iv = iv
    End Sub

    Public Function Encrypt(ByVal input() As Byte) As Byte()
        Return Transform(input, m_des.CreateEncryptor(m_key, m_iv))
    End Function

    Public Function Decrypt(ByVal input() As Byte) As Byte()
        Return Transform(input, m_des.CreateDecryptor(m_key, m_iv))
    End Function

    Public Function Encrypt(ByVal text As String) As String
        Dim input() As Byte = m_utf8.GetBytes(text)
        Dim output() As Byte = Transform(input, _
                        m_des.CreateEncryptor(m_key, m_iv))
        Return Convert.ToBase64String(output)
    End Function

    Public Function Decrypt(ByVal text As String) As String
        Dim input() As Byte = Convert.FromBase64String(text)
        Dim output() As Byte = Transform(input, _
                         m_des.CreateDecryptor(m_key, m_iv))
        Return m_utf8.GetString(output)
    End Function

    Private Function Transform(ByVal input() As Byte, _
        ByVal CryptoTransform As ICryptoTransform) As Byte()
        ' create the necessary streams
        Dim memStream As MemoryStream = New MemoryStream
        Dim cryptStream As CryptoStream = New  _
            CryptoStream(memStream, CryptoTransform, _
            CryptoStreamMode.Write)
        ' transform the bytes as requested
        cryptStream.Write(input, 0, input.Length)
        cryptStream.FlushFinalBlock()
        ' Read the memory stream and convert it back into byte array
        memStream.Position = 0
        Dim result(CType(memStream.Length - 1, System.Int32)) As Byte
        memStream.Read(result, 0, CType(result.Length, System.Int32))
        ' close and release the streams
        memStream.Close()
        cryptStream.Close()
        ' hand back the encrypted buffer
        Return result
    End Function

我使用下面的函数调用它

Imports System.Security.Cryptography
Imports System.IO
Imports System.Text
Module tripledes

    Function Encrypt(ByVal text As String) As String
        ' define the local key and vector byte arrays
        Dim key() As Byte = Encoding.ASCII.GetBytes("MyKeygoeshere12345678901")
        Dim iv() As Byte = Encoding.ASCII.GetBytes("Heretheiv")

        ' instantiate the class with the arrays
        Dim des As New cTripleDES(key, iv)

        ' the value of decryptedData should be "test",
        ' but for our example purposes, let's re-encrypt it
        Return des.Encrypt(text)
    End Function
    Function Decrypt(ByVal text As String) As String
        ' define the local key and vector byte arrays
        Dim key() As Byte = Encoding.ASCII.GetBytes("MyKeygoeshere12345678901")
        Dim iv() As Byte = Encoding.ASCII.GetBytes("Heretheiv")

        ' instantiate the class with the arrays
        Dim des As New cTripleDES(key, iv)

        ' the value of decryptedData should be "test",
        ' but for our example purposes, let's re-encrypt it
        Return des.Decrypt(text)
    End Function
End Module

但是如果我尝试用下面的PHP函数解密它，输出是agkk，而不是Test作为我的输入，正如我所预期的那样。

function decrypt($content){
$key = "MyKeygoeshere12345678901";
$iv = "Heretheiv";
return  mcrypt_cbc(MCRYPT_3DES, $key,  base64_decode($content), MCRYPT_DECRYPT, $iv);
}

有人能告诉我我哪里做错了吗？

Answer 1

有几件事：

1. Use MCRYPT_TripleDES cypher instead.
2. Generate a valid IV.

您还应该包括如何生成加密值。

无论如何，这里有一个工作示例，您可以在您认为合适的时候使用。

<?php

$content = "your_secret_string";
$secret  = "your_secret_key";

$iv = mcrypt_create_iv(mcrypt_get_block_size(MCRYPT_TripleDES, MCRYPT_MODE_CBC), MCRYPT_DEV_RANDOM);

function encrypt($iv, $content, $secret)
{
    return base64_encode(mcrypt_cbc(MCRYPT_TripleDES, $secret, $content, MCRYPT_ENCRYPT, $iv));
}

function decrypt($iv, $content, $secret)
{
    return mcrypt_cbc(MCRYPT_TripleDES, $secret, base64_decode($content), MCRYPT_DECRYPT, $iv);
}

$encrypted = encrypt($iv, $content, $secret);

echo 'Encrypted: '. encrypt($iv, $content, $secret) . '<br>';;
echo 'Decrypted: '. decrypt($iv, $encrypted, $secret) . '<br>';