Hi,
I am just a started of beginner with writing in C#, so sorry if sounds stupid,
I want to write a Encrypt and Decrypt, program, (simple it will encrypt a string of text and write in a file, and if i want to decrypt the file later on)
with the encryption, i have no problem, i can write it in a file.
but when i try to read it and decrypt it, it will gave me an error (just in time error debugging)
Here is the code for the class that i used, (I wrote at first my own Rijendeal encryption but that doesn't work ether)
Code :
Code:
using System;
using System.Text;
using System.Security.Cryptography;
using System****;
using System.Linq;
namespace EncryptStringSample
{
public static class StringCipher
{
// This constant is used to determine the keysize of the encryption algorithm in bits.
// We divide this by 8 within the code below to get the equivalent number of bytes.
private const int Keysize = 256;
// This constant determines the number of iterations for the password bytes generation function.
private const int DerivationIterations = 1000;
public static string Encrypt(string plainText, string passPhrase)
{
// Salt and IV is randomly generated each time, but is preprended to encrypted cipher text
// so that the same Salt and IV values can be used when decrypting.
var saltStringBytes = Generate256BitsOfRandomEntropy();
var ivStringBytes = Generate256BitsOfRandomEntropy();
var plainTextBytes = Encoding.UTF8.GetBytes(plainText);
using (var password = new Rfc2898DeriveBytes(passPhrase, saltStringBytes, DerivationIterations))
{
var keyBytes = password.GetBytes(Keysize / 8);
using (var symmetricKey = new RijndaelManaged())
{
symmetricKey.BlockSize = 256;
symmetricKey.Mode = CipherMode.CBC;
symmetricKey.Padding = PaddingMode.PKCS7;
using (var encryptor = symmetricKey.CreateEncryptor(keyBytes, ivStringBytes))
{
using (var memoryStream = new MemoryStream())
{
using (var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
{
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
cryptoStream.FlushFinalBlock();
// Create the final bytes as a concatenation of the random salt bytes, the random iv bytes and the cipher bytes.
var cipherTextBytes = saltStringBytes;
cipherTextBytes = cipherTextBytes.Concat(ivStringBytes).ToArray();
cipherTextBytes = cipherTextBytes.Concat(memoryStream.ToArray()).ToArray();
memoryStream.Close();
cryptoStream.Close();
return Convert.ToBase64String(cipherTextBytes);
}
}
}
}
}
}
public static string Decrypt(string cipherText, string passPhrase)
{
// Get the complete stream of bytes that represent:
// [32 bytes of Salt] + [32 bytes of IV] + [n bytes of CipherText]
var cipherTextBytesWithSaltAndIv = Convert.FromBase64String(cipherText);
// Get the saltbytes by extracting the first 32 bytes from the supplied cipherText bytes.
var saltStringBytes = cipherTextBytesWithSaltAndIv.Take(Keysize / 8).ToArray();
// Get the IV bytes by extracting the next 32 bytes from the supplied cipherText bytes.
var ivStringBytes = cipherTextBytesWithSaltAndIv.Skip(Keysize / 8).Take(Keysize / 8).ToArray();
// Get the actual cipher text bytes by removing the first 64 bytes from the cipherText string.
var cipherTextBytes = cipherTextBytesWithSaltAndIv.Skip((Keysize / 8) * 2).Take(cipherTextBytesWithSaltAndIv.Length - ((Keysize / 8) * 2)).ToArray();
using (var password = new Rfc2898DeriveBytes(passPhrase, saltStringBytes, DerivationIterations))
{
var keyBytes = password.GetBytes(Keysize / 8);
using (var symmetricKey = new RijndaelManaged())
{
symmetricKey.BlockSize = 256;
symmetricKey.Mode = CipherMode.CBC;
symmetricKey.Padding = PaddingMode.PKCS7;
using (var decryptor = symmetricKey.CreateDecryptor(keyBytes, ivStringBytes))
{
using (var memoryStream = new MemoryStream(cipherTextBytes))
{
using (var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))
{
var plainTextBytes = new byte[cipherTextBytes.Length];
var decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
memoryStream.Close();
cryptoStream.Close();
return Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
}
}
}
}
}
}
private static byte[] Generate256BitsOfRandomEntropy()
{
var randomBytes = new byte[32]; // 32 Bytes will give us 256 bits.
using (var rngCsp = new RNGCryptoServiceProvider())
{
// Fill the array with cryptographically secure random bytes.
rngCsp.GetBytes(randomBytes);
}
return randomBytes;
}
}
}
Here the Encryption Code,
Code:
Code:
StreamWriter writer = new StreamWriter("C:/Users/Ryan/Documents/Password/data.txt", true);
string Code = "2000";
string App = textBox4.Text;
string Username = textBox3.Text;
string Password = textBox5.Text;
string AppEncrypted = StringCipher.Encrypt(App, Code);
string UsernameEncrypted = StringCipher.Encrypt(Username, Code);
string PasswordEncrypted = StringCipher.Encrypt(Password, Code);
writer.WriteLine(AppEncrypted);
writer.WriteLine(UsernameEncrypted);
writer.WriteLine(UsernameEncrypted);
writer.WriteLine(" ");
writer.Flush();
writer.Close();
MessageBox.Show("Saved succesfull");
Code for Decryption
Code:
Code:
// Read the file and display it line by line.
StreamReader file = new System****.StreamReader(@"C:\Users\Ryan\Documents\Password\Data.txt");
while (true)
{
string Line = file.ReadLine();
if (Line == "" && Line == " ")
{
break;
}
else
{
string LineDecrypted = StringCipher.Decrypt(Line, "2000");
richTextBox1.AppendText(LineDecrypted);
}
}
file.Close();
if i used this code, i get an error,
But if i only Decode 1 string there isn't an error,
I hope one of you could help me out,
attached, Visual Studio Full file,
https://virustotal.com/en/file/0745a...is/1481229877/
https://virusscan.jotti.org/en-US/fi...job/x8fa4p3sy5