Encrypt decrypt

Question

hi  i want to encrypt and decrypt a string. to encrypt i have this: string toencode; byte[] text; text = Encoding.Unicode.GetBytes(toencode); SHA256Managed hash = new SHA256Managed(); texto = hash.ComputeHash(text); Convert.ToBase64String(text); to decrypt how can i do it? thanks in advance

trkpower · Answer

thanks. :) i tried doing with SHA1 but i'm getting a error saying Specified key is not a valid size for this algorithm. do you know what could it be? Thanks in advance.

Scott Lysle · Answer

Encryption and decryption with a passkey: using System; using System.Security.Cryptography; using System.Text; #pragma warning disable 159115921573157115701572 namespace Crypto { public static class Endecrypto { #region MD5 Hash /// /// MD5 - Encrypt a plain text string using a key /// /// /// /// A string containing the encrypted password public static string EncryptMd5( string sOriginal string sPassKey) { byte [] sPassKeyArray; byte [] sOriginalArray = UTF8Encoding .UTF8.GetBytes(sOriginal); MD5CryptoServiceProvider MD5Hash = new MD5CryptoServiceProvider (); sPassKeyArray = MD5Hash.ComputeHash( UTF8Encoding .UTF8.GetBytes(sPassKey)); MD5Hash.Clear(); TripleDESCryptoServiceProvider tripleDesCsp = new TripleDESCryptoServiceProvider (); tripleDesCsp.Key = sPassKeyArray; tripleDesCsp.Mode = CipherMode .ECB; tripleDesCsp.Padding = PaddingMode .PKCS7; ICryptoTransform cTransform = tripleDesCsp.CreateEncryptor(); byte [] resultArray = cTransform.TransformFinalBlock(sOriginalArray 0 sOriginalArray.Length); tripleDesCsp.Clear(); return Convert .ToBase64String(resultArray 0 resultArray.Length); } /// /// MD5 - Decrypt an encrypted string using a key /// /// /// /// A string containing the decrypted account number public static string DecryptMd5( string sToOriginal string sPassKey) { byte [] sPassKeyArray; byte [] sOriginalArray = Convert .FromBase64String(sToOriginal); MD5CryptoServiceProvider MD5Hash = new MD5CryptoServiceProvider (); sPassKeyArray = MD5Hash.ComputeHash( UTF8Encoding .UTF8.GetBytes(sPassKey)); MD5Hash.Clear(); TripleDESCryptoServiceProvider tripleDesCsp = new TripleDESCryptoServiceProvider (); tripleDesCsp.Key = sPassKeyArray; tripleDesCsp.Mode = CipherMode .ECB; tripleDesCsp.Padding = PaddingMode .PKCS7; ICryptoTransform cTransform = tripleDesCsp.CreateDecryptor(); byte [] resultArray = cTransform.TransformFinalBlock(sOriginalArray 0 sOriginalArray.Length); tripleDesCsp.Clear(); return UTF8Encoding .UTF8.GetString(resultArray); } #endregion } }