I want to decrypt in VB.net strings encrypted in PHP via openssl_encrypt function:
$encrypted_string = openssl_encrypt(
$string,
'AES256',
'secret_password',
0,
'initialization_vector'
);
I tried with this class:
Public Class Aes256Encrypter
Public Function Encrypt(ByVal plainText As String, ByVal secretKey As String) As Byte()
Dim encryptedPassword As Byte()
Using outputStream As MemoryStream = New MemoryStream()
Dim algorithm As RijndaelManaged = getAlgorithm(secretKey)
Using cryptoStream As CryptoStream = New CryptoStream(outputStream, algorithm.CreateEncryptor(), CryptoStreamMode.Write)
Dim inputBuffer() As Byte = Encoding.Unicode.GetBytes(plainText)
cryptoStream.Write(inputBuffer, 0, inputBuffer.Length)
cryptoStream.FlushFinalBlock()
encryptedPassword = outputStream.ToArray()
End Using
End Using
Return encryptedPassword
End Function
Public Function Decrypt(ByVal encryptedBytes As Byte(), ByVal secretKey As String) As String
Dim plainText As String = Nothing
Using inputStream As MemoryStream = New MemoryStream(encryptedBytes)
Dim algorithm As RijndaelManaged = getAlgorithm(secretKey)
Using cryptoStream As CryptoStream = New CryptoStream(inputStream, algorithm.CreateDecryptor(), CryptoStreamMode.Read)
Dim outputBuffer(0 To CType(inputStream.Length - 1, Integer)) As Byte
Dim readBytes As Integer = cryptoStream.Read(outputBuffer, 0, CType(inputStream.Length, Integer))
plainText = Encoding.Unicode.GetString(outputBuffer, 0, readBytes)
End Using
End Using
Return plainText
End Function
Private Function getAlgorithm(ByVal secretKey As String) As RijndaelManaged
Const salt As String = "put your salt here"
Const keySize As Integer = 256
Dim keyBuilder As Rfc2898DeriveBytes = New Rfc2898DeriveBytes(secretKey, Encoding.Unicode.GetBytes(salt))
Dim algorithm As RijndaelManaged = New RijndaelManaged()
algorithm.KeySize = keySize
algorithm.IV = keyBuilder.GetBytes(CType(algorithm.BlockSize / 8, Integer))
algorithm.Key = keyBuilder.GetBytes(CType(algorithm.KeySize / 8, Integer))
algorithm.Padding = PaddingMode.PKCS7
Return algorithm
End Function
End Class
I use IV "initialization_vector" as salt string, but at runtime an error is thrown: 'System.Security.Cryptography.CryptographicException' in mscorlib.dll. An error occurred: Padding is invalid and cannot be removed.
Where am I doing wrong?
