/
ExampleFileEncryption.cs
94 lines (82 loc) · 3.3 KB
/
ExampleFileEncryption.cs
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using System;
using System.Security.Cryptography;
using System.IO;
using Serilog;
namespace com.cryptoexamples.csharp
{
public static class ExampleFileEncryption
{
public static void Main()
{
Log.Logger = new LoggerConfiguration().WriteTo.Console().CreateLogger();
Log.Information(DemonstrateFileEncryption("Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua.", "ThePasswordToDecryptAndEncryptTheFile"));
}
public static String DemonstrateFileEncryption(String plainText, string password)
{
String inputFile = @"encryptedFile.enc";
//Generating random salt
byte[] salt = new byte[32];
using (RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider())
{
for (int i = 0; i < 10; i++)
{
// Fille the buffer with the generated data
rng.GetBytes(salt);
}
}
//Encryption
//convert password string to byte arrray
byte[] passwordBytes = System.Text.Encoding.UTF8.GetBytes(password);
//Set Rijndael symmetric encryption algorithm
RijndaelManaged AES = new RijndaelManaged
{
KeySize = 256,
BlockSize = 128,
Padding = PaddingMode.PKCS7
};
var key = new Rfc2898DeriveBytes(passwordBytes, salt, 50000);
AES.Key = key.GetBytes(AES.KeySize / 8);
AES.IV = key.GetBytes(AES.BlockSize / 8);
AES.Mode = CipherMode.CBC;
//create output file name
using (FileStream fsCrypt = new FileStream(inputFile, FileMode.Create))
{
// write salt to the begining of the output file, so in this case can be random every time
fsCrypt.Write(salt, 0, salt.Length);
using (CryptoStream cs = new CryptoStream(fsCrypt, AES.CreateEncryptor(), CryptoStreamMode.Write))
{
byte[] plaintextBytes = System.Text.Encoding.UTF8.GetBytes(plainText);
try
{
cs.Write(plaintextBytes);
}
catch (Exception ex)
{
Log.Error(ex.Message);
}
}
}
//Decryption
String decryptString = "";
using (FileStream fsCrypt = new FileStream(inputFile, FileMode.Open))
{
fsCrypt.Read(salt, 0, salt.Length);
using (CryptoStream cs2 = new CryptoStream(fsCrypt, AES.CreateDecryptor(), CryptoStreamMode.Read))
{
using (StreamReader fsOut = new StreamReader(cs2))
{
try
{
decryptString = fsOut.ReadToEnd();
}
catch (CryptographicException e)
{
Log.Error(e.Message);
}
}
}
}
return decryptString;
}
}
}