Question

大约有100,000种不同的加密字符串的方法。使用AES，CBC和PKCS7等标准可以使事情变得更容易 - 但IV仍然存在问题。盐，编码等（如www.Crypto.Stackexchange.com所述）

对于我的iOS项目（Obj-C），我使用的是FBEncryptor project，这是一种简单且记录良好的加密字符串的方法。但是，我需要能够在Windows平台上解密由FBEncryptor生成的iOS AES字符串的代码 - 最好是VB.NET。

我还没有找到另一个与FBEncryptor兼容的VB.NET项目。

有谁知道任何与FBEncryptor一起使用的VB.NET加密项目？如果没有，那么我需要做些什么来使Rijndael Managed库（由Microsoft提供）与FBEncryptor一起使用？

我的VB.NET代码使用Rijndael Managed：

Imports System.Security
Imports System.Security.Cryptography
Imports System.IO
Imports System.Runtime.InteropServices
Imports System.Text.RegularExpressions
Imports System.Text


Module Encrypt2
Public saltBytes As Byte()
Dim hashAlgorithm As String = "SHA1"

Public Sub GenerateSalt()
    ' Define min and max salt sizes.
    Dim minSaltSize As Integer
    Dim maxSaltSize As Integer

    minSaltSize = 8
    maxSaltSize = 8

    ' Generate a random number for the size of the salt.
    Dim random As Random
    random = New Random()

    Dim saltSize As Integer
    saltSize = random.Next(minSaltSize, maxSaltSize)

    ' Allocate a byte array, which will hold the salt.
    saltBytes = New Byte(saltSize - 1) {}

    ' Initialize a random number generator.
    Dim rng As RNGCryptoServiceProvider
    rng = New RNGCryptoServiceProvider()

    ' Fill the salt with cryptographically strong byte values.
    rng.GetNonZeroBytes(saltBytes)
End Sub

Public Function Encrypt(ByVal plainText As String, ByVal keyword As String) As String
    Dim hashAlgorithm As String = "SHA1"
    Dim passwordIterations As Integer = 128
    Dim initVector As String = "@7781157e2629b09"
    Dim keySize As Integer = 256

    Dim initVectorBytes As Byte() = Encoding.ASCII.GetBytes(initVector)

    Dim plainTextBytes As Byte() = Encoding.ASCII.GetBytes(plainText)

    GenerateSalt()

    Dim password As New Rfc2898DeriveBytes(keyword, saltBytes, passwordIterations)

    Dim keyBytes As Byte() = password.GetBytes(keySize \ 8)
    Dim symmetricKey As New RijndaelManaged()

    symmetricKey.Mode = CipherMode.CBC

    Dim encryptor As ICryptoTransform = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes)

    Dim memoryStream As New MemoryStream()
    Dim cryptoStream As New CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write)

    cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length)
    cryptoStream.FlushFinalBlock()
    Dim cipherTextBytes As Byte() = memoryStream.ToArray()
    memoryStream.Close()
    cryptoStream.Clear()

    Dim cipherText As String = Convert.ToBase64String(cipherTextBytes)

    Return (cipherText)

End Function

Public Function Decrypt(ByVal cipherText As String, ByVal keyword As String) As String

    Dim hashAlgorithm As String = "SHA1"

    Dim passwordIterations As Integer = 128
    Dim initVector As String = "@7781157e2629b09"
    Dim keySize As Integer = 256

    ' Convert strings defining encryption key characteristics into Byte
    ' arrays. Let us assume that strings only contain ASCII codes.
    ' If strings include Unicode characters, use Unicode, UTF7, or UTF8
    ' encoding

    Dim initVectorBytes As Byte() = Encoding.ASCII.GetBytes(initVector)

    ' Convert the Ciphertext into a Byte array
    Dim cipherTextBytes As Byte() = Encoding.ASCII.GetBytes(cipherText)

    ' First we must create a password, from which the key will be 
    ' derived. This password will be generated from the specified
    ' passphrase and salt value. The password will be created using 
    ' the specified hash algorithm. Password creation can be done in 
    ' several iterations
    GenerateSalt()
    Dim password As New Rfc2898DeriveBytes(keyword, saltBytes, passwordIterations)

    ' Use the password to generate pseudo-random bytes for the encryption
    ' key. Specify the size of the key in bytes (instead of bits)

    Dim keyBytes As Byte() = password.GetBytes(keySize \ 8)

    ' Create uninitialized Rijndael encryption object

    Dim symmetricKey As New RijndaelManaged()

    ' It is reasonable to set encryption mode to Cipher Block Chaining
    ' (CBC). Use default options for other symmetric key parameters.
    symmetricKey.Mode = CipherMode.CBC

    ' Generate decryptor from the existing key bytes and initialization
    ' vector. Key size will be defined based on the number of the key
    'bytes

    Dim decryptor As ICryptoTransform = symmetricKey.CreateDecryptor(keyBytes, initVectorBytes)

    ' Define memory stream which will be used to hold encrypted data.

    Dim memoryStream As New MemoryStream(cipherTextBytes)

    ' Define cryptographic stream (always user Read mode for encryption).
    Dim cryptoStream As New CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read)


    ' Since at this point we don't know what the size of decrypted data
    ' will be, allocate the buffer long enough to hold ciphertext;
    ' plaintext is never longer than ciphertext
    Dim plainTextBytes As Byte() = New Byte(cipherTextBytes.Length - 1) {}

    ' Start decrypting.
    Dim decryptedByteCount As Integer = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length)

    ' Close both streams
    memoryStream.Close()
    cryptoStream.Close()

    ' Convert decrypted data into a string
    ' Let us assume that the original plaintext string was UTF8-Encoded.
    Dim plainText As String = Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount)

    ' Return the decrypted string
    Return (plainText)


End Function

End Module

你会注意到IV是静态的，密码迭代很少。这是因为我不确定如何以与FBEncryptor相同的方法生成IV。您可能还注意到，在尝试解密时，字节长度存在问题。

任何帮助将不胜感激！谢谢！

Answer 1

一个注意事项。我看着FBEncryptor。它使用了一些不好的做法。因此，如果安全性对您很重要，我建议您再多阅读一下，并选择另一个加密代码（或者自己编写）。

FBEncryptor确实关注加密 a）将字符串转换为字节数组（基于UTF8编码） b）将密钥转换为字节数组（基于UTF编码）。 c）仅复制前16个字节的密钥 d）创建IV，即16位0x00 e）使用AES / CBC / PKCS7Padding加密来自项目a）的字节数组，并在d）中创建IV f）生成的加密数据转换为Base64

它确实遵循解密 a）将加密字符串从Base64转换为字节数组 b）将密钥转换为字节数组（基于UTF编码）。 c）仅复制前16个字节的密钥 d）创建IV，即16位0x00 e）使用AES / CBC / PKCS7Padding在d）中创建IV，从项目a）解密字节数组 f）使用UTF8编码将加密数据从e）转换为字符串

你应该在VB.NET中做同样的事情。我想你几乎所有的部分 - 您将需要删除所有SHA1和盐相关的东西，并使用相同的步骤b）。你需要研究用于VB.NET的PKCS7Padding

Obj-C和VB.Net之间的加密兼容性

1 个答案: