Below are the algorithm which I find as simple and best.
First
Note: Keys defined in "rgbIV" and "key" should be 16 and 32 characters respectively.
First
/////////////////////////////////////////////////////////////////////////////// // SAMPLE: Symmetric key encryption and decryption using Rijndael algorithm. // // To run this sample, create a new Visual C# project using the Console // Application template and replace the contents of the Class1.cs file with // the code below. // // 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. // // Copyright (C) 2002 Obviex(TM). All rights reserved. // using System; using System.IO; using System.Text; using System.Security.Cryptography; ///Second/// This class uses a symmetric key algorithm (Rijndael/AES) to encrypt and /// decrypt data. As long as encryption and decryption routines use the same /// parameters to generate the keys, the keys are guaranteed to be the same. /// The class uses static functions with duplicate code to make it easier to /// demonstrate encryption and decryption logic. In a real-life application, /// this may not be the most efficient way of handling encryption, so - as /// soon as you feel comfortable with it - you may want to redesign this class. /// public class RijndaelSimple { ////// Encrypts specified plaintext using Rijndael symmetric key algorithm /// and returns a base64-encoded result. /// /// /// Plaintext value to be encrypted. /// /// /// Passphrase from which a pseudo-random password will be derived. The /// derived password will be used to generate the encryption key. /// Passphrase can be any string. In this example we assume that this /// passphrase is an ASCII string. /// /// /// Salt value used along with passphrase to generate password. Salt can /// be any string. In this example we assume that salt is an ASCII string. /// /// /// Hash algorithm used to generate password. Allowed values are: "MD5" and /// "SHA1". SHA1 hashes are a bit slower, but more secure than MD5 hashes. /// /// /// Number of iterations used to generate password. One or two iterations /// should be enough. /// /// /// Initialization vector (or IV). This value is required to encrypt the /// first block of plaintext data. For RijndaelManaged class IV must be /// exactly 16 ASCII characters long. /// /// /// Size of encryption key in bits. Allowed values are: 128, 192, and 256. /// Longer keys are more secure than shorter keys. /// ////// Encrypted value formatted as a base64-encoded string. /// public static string Encrypt(string plainText, string passPhrase, string saltValue, string hashAlgorithm, int passwordIterations, string initVector, int keySize) { // Convert strings into byte arrays. // Let us assume that strings only contain ASCII codes. // If strings include Unicode characters, use Unicode, UTF7, or UTF8 // encoding. byte[] initVectorBytes = Encoding.ASCII.GetBytes(initVector); byte[] saltValueBytes = Encoding.ASCII.GetBytes(saltValue); // Convert our plaintext into a byte array. // Let us assume that plaintext contains UTF8-encoded characters. byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText); // First, we must create a password, from which the key will be derived. // This password will be generated from the specified passphrase and // salt value. The password will be created using the specified hash // algorithm. Password creation can be done in several iterations. PasswordDeriveBytes password = new PasswordDeriveBytes( passPhrase, saltValueBytes, hashAlgorithm, passwordIterations); // Use the password to generate pseudo-random bytes for the encryption // key. Specify the size of the key in bytes (instead of bits). byte[] keyBytes = password.GetBytes(keySize / 8); // Create uninitialized Rijndael encryption object. RijndaelManaged symmetricKey = new RijndaelManaged(); // It is reasonable to set encryption mode to Cipher Block Chaining // (CBC). Use default options for other symmetric key parameters. symmetricKey.Mode = CipherMode.CBC; // Generate encryptor from the existing key bytes and initialization // vector. Key size will be defined based on the number of the key // bytes. ICryptoTransform encryptor = symmetricKey.CreateEncryptor( keyBytes, initVectorBytes); // Define memory stream which will be used to hold encrypted data. MemoryStream memoryStream = new MemoryStream(); // Define cryptographic stream (always use Write mode for encryption). CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write); // Start encrypting. cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length); // Finish encrypting. cryptoStream.FlushFinalBlock(); // Convert our encrypted data from a memory stream into a byte array. byte[] cipherTextBytes = memoryStream.ToArray(); // Close both streams. memoryStream.Close(); cryptoStream.Close(); // Convert encrypted data into a base64-encoded string. string cipherText = Convert.ToBase64String(cipherTextBytes); // Return encrypted string. return cipherText; } ////// Decrypts specified ciphertext using Rijndael symmetric key algorithm. /// /// /// Base64-formatted ciphertext value. /// /// /// Passphrase from which a pseudo-random password will be derived. The /// derived password will be used to generate the encryption key. /// Passphrase can be any string. In this example we assume that this /// passphrase is an ASCII string. /// /// /// Salt value used along with passphrase to generate password. Salt can /// be any string. In this example we assume that salt is an ASCII string. /// /// /// Hash algorithm used to generate password. Allowed values are: "MD5" and /// "SHA1". SHA1 hashes are a bit slower, but more secure than MD5 hashes. /// /// /// Number of iterations used to generate password. One or two iterations /// should be enough. /// /// /// Initialization vector (or IV). This value is required to encrypt the /// first block of plaintext data. For RijndaelManaged class IV must be /// exactly 16 ASCII characters long. /// /// /// Size of encryption key in bits. Allowed values are: 128, 192, and 256. /// Longer keys are more secure than shorter keys. /// ////// Decrypted string value. /// ////// Most of the logic in this function is similar to the Encrypt /// logic. In order for decryption to work, all parameters of this function /// - except cipherText value - must match the corresponding parameters of /// the Encrypt function which was called to generate the /// ciphertext. /// public static string Decrypt(string cipherText, string passPhrase, string saltValue, string hashAlgorithm, int passwordIterations, string initVector, int keySize) { // Convert strings defining encryption key characteristics into byte // arrays. Let us assume that strings only contain ASCII codes. // If strings include Unicode characters, use Unicode, UTF7, or UTF8 // encoding. byte[] initVectorBytes = Encoding.ASCII.GetBytes(initVector); byte[] saltValueBytes = Encoding.ASCII.GetBytes(saltValue); // Convert our ciphertext into a byte array. byte[] cipherTextBytes = Convert.FromBase64String(cipherText); // First, we must create a password, from which the key will be // derived. This password will be generated from the specified // passphrase and salt value. The password will be created using // the specified hash algorithm. Password creation can be done in // several iterations. PasswordDeriveBytes password = new PasswordDeriveBytes( passPhrase, saltValueBytes, hashAlgorithm, passwordIterations); // Use the password to generate pseudo-random bytes for the encryption // key. Specify the size of the key in bytes (instead of bits). byte[] keyBytes = password.GetBytes(keySize / 8); // Create uninitialized Rijndael encryption object. RijndaelManaged symmetricKey = new RijndaelManaged(); // It is reasonable to set encryption mode to Cipher Block Chaining // (CBC). Use default options for other symmetric key parameters. symmetricKey.Mode = CipherMode.CBC; // Generate decryptor from the existing key bytes and initialization // vector. Key size will be defined based on the number of the key // bytes. ICryptoTransform decryptor = symmetricKey.CreateDecryptor( keyBytes, initVectorBytes); // Define memory stream which will be used to hold encrypted data. MemoryStream memoryStream = new MemoryStream(cipherTextBytes); // Define cryptographic stream (always use Read mode for encryption). CryptoStream cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read); // Since at this point we don't know what the size of decrypted data // will be, allocate the buffer long enough to hold ciphertext; // plaintext is never longer than ciphertext. byte[] plainTextBytes = new byte[cipherTextBytes.Length]; // Start decrypting. int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length); // Close both streams. memoryStream.Close(); cryptoStream.Close(); // Convert decrypted data into a string. // Let us assume that the original plaintext string was UTF8-encoded. string plainText = Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount); // Return decrypted string. return plainText; } } ////// Illustrates the use of RijndaelSimple class to encrypt and decrypt data. /// public class RijndaelSimpleTest { ////// The main entry point for the application. /// [STAThread] static void Main(string[] args) { string plainText = "Hello, World!"; // original plaintext string passPhrase = "Pas5pr@se"; // can be any string string saltValue = "s@1tValue"; // can be any string string hashAlgorithm = "SHA1"; // can be "MD5" int passwordIterations = 2; // can be any number string initVector = "@1B2c3D4e5F6g7H8"; // must be 16 bytes int keySize = 256; // can be 192 or 128 Console.WriteLine(String.Format("Plaintext : {0}", plainText)); string cipherText = RijndaelSimple.Encrypt(plainText, passPhrase, saltValue, hashAlgorithm, passwordIterations, initVector, keySize); Console.WriteLine(String.Format("Encrypted : {0}", cipherText)); plainText = RijndaelSimple.Decrypt(cipherText, passPhrase, saltValue, hashAlgorithm, passwordIterations, initVector, keySize); Console.WriteLine(String.Format("Decrypted : {0}", plainText)); } } // // END OF FILE ///////////////////////////////////////////////////////////////////////////////
Note: Keys defined in "rgbIV" and "key" should be 16 and 32 characters respectively.
public string EncryptString(string ClearText)
{
byte[] clearTextBytes = Encoding.UTF8.GetBytes(ClearText);
System.Security.Cryptography.SymmetricAlgorithm rijn = SymmetricAlgorithm.Create();
MemoryStream ms = new MemoryStream();
byte[] rgbIV = Encoding.ASCII.GetBytes("ryojvlzmdalyglrj");
byte[] key = Encoding.ASCII.GetBytes("hcxilkqbbhczfeultgbskdmaunivmfuo");
CryptoStream cs = new CryptoStream(ms, rijn.CreateEncryptor(key, rgbIV),
CryptoStreamMode.Write);
cs.Write(clearTextBytes, 0, clearTextBytes.Length);
cs.Close();
return Convert.ToBase64String(ms.ToArray());
}
private string DecryptString(string EncryptedText)
{
byte[] encryptedTextBytes = Convert.FromBase64String(EncryptedText);
MemoryStream ms = new MemoryStream();
System.Security.Cryptography.SymmetricAlgorithm rijn = SymmetricAlgorithm.Create();
byte[] rgbIV = Encoding.ASCII.GetBytes("ryojvlzmdalyglrj");
byte[] key = Encoding.ASCII.GetBytes("hcxilkqbbhczfeultgbskdmaunivmfuo");
CryptoStream cs = new CryptoStream(ms, rijn.CreateDecryptor(key, rgbIV),
CryptoStreamMode.Write);
cs.Write(encryptedTextBytes, 0, encryptedTextBytes.Length);
cs.Close();
return Encoding.UTF8.GetString(ms.ToArray());
}
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