ios - Obj-C 和 VB.Net 之间的加密兼容性

Question

加密字符串的方法大约有 100,000 种。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)，我正在使用 FBEncryptor project这是一种加密字符串的简单且有据可查的方法。但是，我需要能够解密 FBEncryptor 在 Windows 平台上生成的 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。

有人知道任何与 FBEncryptor 一起工作的 VB.NET 加密项目吗？如果不是，那么我需要做什么才能使 Rijndael 托管库(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

您会注意到 IV 是静态的并且密码迭代次数很少。这是因为我不确定如何使用与 FBEncryptor 相同的方法生成 IV。您可能还会注意到，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

一张纸条。我查看了 FBEncryptor。它使用了一些不好的做法。因此，如果安全性对您很重要，我建议您阅读更多相关内容并选择另一个进行加密的代码(或自行编写)。

FBEncryptor 做以下加密a) 字符串转字节数组(基于UTF8编码)b) 将 key 转换为字节数组(基于 UTF 编码)。c) 仅复制 key 的前 16 个字节d) 创建 IV，它是 0x00 的 16 个字节e) 使用 AES/CBC/PKCS7Padding 和在 d) 中创建的 IV 加密项目 a) 中的字节数组f) 将得到的加密数据转为Base64

它会进行以下解密a) 将加密字符串从 Base64 转换为字节数组b) 将 key 转换为字节数组(基于 UTF 编码)。c) 仅复制 key 的前 16 个字节d) 创建 IV，它是 0x00 的 16 个字节e) 使用 AES/CBC/PKCS7Padding 和在 d) 中创建的 IV 解密项目 a) 中的字节数组f) 使用 UTF8 编码将 e) 中的加密数据转换为字符串

您应该在 VB.NET 中做完全相同的事情。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步骤 b) 的等价物。你需要研究 PKCS7Padding for VB.NET