/*
THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
This is sample code and is freely distributable.
*/
using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
using System.Web;
namespace Wmb.Web {
/// <summary>
/// The StringUtility class holds the extensions and/or helpermethods for the String class.
/// </summary>
public static class EcryptionUtility {
/// <summary>
/// Encrypts the value by password and salt.
/// </summary>
/// <param name="value">The value.</param>
/// <param name="password">The password.</param>
/// <param name="salt">The salt.</param>
/// <returns>The encrypted bytes</returns>
public static byte[] PasswordEncrypt(this byte[] value, string password, string salt) {
if (value == null) {
throw new ArgumentNullException("value");
}
if (string.IsNullOrEmpty(password)) {
throw new ArgumentNullException("password");
}
if (string.IsNullOrEmpty(salt)) {
throw new ArgumentNullException("salt");
}
byte[] retVal = null;
Rijndael rijndaelAlg = CreateRijndael(password, salt);
using (MemoryStream memoryStream = new MemoryStream())
using (CryptoStream cryptoStream = new CryptoStream(memoryStream,
rijndaelAlg.CreateEncryptor(),
CryptoStreamMode.Write)) {
cryptoStream.Write(value, 0, value.Length);
cryptoStream.Close();
retVal = memoryStream.ToArray();
}
return retVal;
}
/// <summary>
/// Decrypts the value by password and salt.
/// </summary>
/// <param name="value">The value.</param>
/// <param name="password">The password.</param>
/// <param name="salt">The salt.</param>
/// <returns>The decrypted bytes</returns>
public static byte[] PasswordDecrypt(this byte[] value, string password, string salt) {
if (value == null) {
throw new ArgumentNullException("value");
}
if (string.IsNullOrEmpty(password)) {
throw new ArgumentNullException("password");
}
if (string.IsNullOrEmpty(salt)) {
throw new ArgumentNullException("salt");
}
byte[] retVal = null;
Rijndael rijndaelAlg = CreateRijndael(password, salt);
using (MemoryStream memoryStream = new MemoryStream())
using (CryptoStream cryptoStream = new CryptoStream(memoryStream,
rijndaelAlg.CreateDecryptor(),
CryptoStreamMode.Write)) {
cryptoStream.Write(value, 0, value.Length);
cryptoStream.Close();
retVal = memoryStream.ToArray();
}
return retVal;
}
/// <summary>
/// Ecrypts the value to a url encoded string.
/// </summary>
/// <param name="value">The value.</param>
/// <param name="password">The password.</param>
/// <param name="salt">The salt.</param>
/// <returns>The encrypted and url encoded string</returns>
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1055:UriReturnValuesShouldNotBeStrings", Justification="This method does not return a Uri.")]
public static string UrlEncodedPasswordEncrypt(this string value, string password, string salt) {
if (value == null) {
throw new ArgumentNullException("value");
}
if (string.IsNullOrEmpty(password)) {
throw new ArgumentNullException("password");
}
if (string.IsNullOrEmpty(salt)) {
throw new ArgumentNullException("salt");
}
string retVal = null;
byte[] bytesToEncrypt = Encoding.Unicode.GetBytes(value);
byte[] encryptedValue = bytesToEncrypt.PasswordEncrypt(password, salt);
retVal = HttpServerUtility.UrlTokenEncode(encryptedValue);
return retVal;
}
/// <summary>
/// Decrypts the url encoded value.
/// </summary>
/// <param name="value">The value.</param>
/// <param name="password">The password.</param>
/// <param name="salt">The salt.</param>
/// <returns>The decrypted and url decoded string</returns>
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1055:UriReturnValuesShouldNotBeStrings", Justification="This method does not return a Uri.")]
public static string UrlEncodedPasswordDecrypt(this string value, string password, string salt) {
if (value == null) {
throw new ArgumentNullException("value");
}
if (string.IsNullOrEmpty(password)) {
throw new ArgumentNullException("password");
}
if (string.IsNullOrEmpty(salt)) {
throw new ArgumentNullException("salt");
}
string retVal = null;
byte[] bytesToDecrypt = HttpServerUtility.UrlTokenDecode(value);
byte[] decryptedValue = bytesToDecrypt.PasswordDecrypt(password, salt);
retVal = Encoding.Unicode.GetString(decryptedValue);
return retVal;
}
private static Rijndael CreateRijndael(string password, string salt) {
byte[] saltBytes = Encoding.Unicode.GetBytes(salt);
PasswordDeriveBytes passwordDeriveBytes = new PasswordDeriveBytes(password,
saltBytes);
Rijndael rijndael = Rijndael.Create();
rijndael.Key = passwordDeriveBytes.GetBytes(32);
rijndael.IV = passwordDeriveBytes.GetBytes(16);
return rijndael;
}
}
}
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