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Padding problem with AesManaged
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using System; | |
using System.IO; | |
using System.Security.Cryptography; | |
using System.Text; | |
namespace CryptoTest | |
{ | |
class Program | |
{ | |
static void Main(string[] args) | |
{ | |
string text = "Buy my book, available now from Wrox Press"; | |
byte[] data = Encoding.UTF8.GetBytes(text); | |
byte[] encrypted; | |
byte[] decrypted; | |
var encryptor = GetEncryptor(); | |
using (var ms = new MemoryStream()) | |
using (var encrypt = new CryptoStream(ms, encryptor.CreateEncryptor(), CryptoStreamMode.Write)) | |
{ | |
encrypt.Write(data, 0, data.Length); | |
encrypt.FlushFinalBlock(); | |
encrypted = ms.ToArray(); | |
} | |
// "Correct" approach. By initialising the MemoryStream with the encrypted data you're fixing the length | |
// So instead do the same as you did during encryption, except create a decryptor. | |
// Start with an empty MemoryStream, attach the CryptoStream to it, then write the encrypted data | |
// into the CryptoStream, flush, and tada. | |
using (var ms = new MemoryStream()) | |
using (var decrypt = new CryptoStream(ms, encryptor.CreateDecryptor(), CryptoStreamMode.Write)) | |
{ | |
decrypt.Write(encrypted, 0, encrypted.Length); | |
decrypt.FlushFinalBlock(); | |
decrypted = ms.ToArray(); | |
} | |
Console.WriteLine("Data length: {0}", data.Length); | |
Console.WriteLine("Encrypted length: {0}", encrypted.Length); | |
Console.WriteLine("Decrypted length: {0}", decrypted.Length); | |
Console.WriteLine(); | |
Console.WriteLine("Original content: -{0}-", text); | |
Console.WriteLine("Decrypted content: -{0}-", Encoding.UTF8.GetString(decrypted)); | |
Console.ReadLine(); | |
} | |
private static AesManaged GetEncryptor() | |
{ | |
string key = "this is my super secret key bojah!"; | |
byte[] keyBytes = Encoding.UTF8.GetBytes(key); | |
var rfc = new Rfc2898DeriveBytes(key, keyBytes, 1000); | |
var encryptor = new AesManaged(); | |
encryptor.Key = rfc.GetBytes(16); | |
encryptor.IV = rfc.GetBytes(16); | |
return encryptor; | |
} | |
} | |
} |
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