//A CONTINUACION funciones cifrarTextoAES y descifrarTextoAES para cifrar/descif rar (encriptar/desencriptar) una cadena de texto usando el mtodo //Advanced Encryption Standard (AES) Rijndael. Mostramos el cdigo completo de la cl ase "cifrarAES.cs". //Las funciones de cifrado y descifrado permitirn elegir el algoritmo hash de encr iptacin (MD5, SHA1) y el tamao de la clave: 128, 192 o 256. using System; using System.Security.Cryptography; using System.Text; using System.IO; namespace AjpdSoftIndexarTextoFicherosPDF { class cifrarAES { public string cifrarTextoAES (string textoCifrar, string palabraPaso, string valorRGBSalt, string algoritmoEncriptacionHASH, int iteraciones, string vectorInicial, int tamanoClave) { try { byte[] InitialVectorBytes = Encoding.ASCII.GetBytes(vectorInicia l); byte[] saltValueBytes = Encoding.ASCII.GetBytes(valorRGBSalt); byte[] plainTextBytes = Encoding.UTF8.GetBytes(textoCifrar); PasswordDeriveBytes password = new PasswordDeriveBytes(palabraPaso, saltValueBytes, algoritmoEncriptacionHASH, iteraciones); byte[] keyBytes = password.GetBytes(tamanoClave / 8); RijndaelManaged symmetricKey = new RijndaelManaged(); symmetricKey.Mode = CipherMode.CBC; ICryptoTransform encryptor = symmetricKey.CreateEncryptor(keyBytes, InitialVectorBytes); MemoryStream memoryStream = new MemoryStream(); CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.W rite); cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length); cryptoStream.FlushFinalBlock(); byte[] cipherTextBytes = memoryStream.ToArray(); memoryStream.Close(); cryptoStream.Close(); string textoCifradoFinal = Convert.ToBase64String(cipherTextByte s); return textoCifradoFinal; } catch

{ return null; } } public string descifrarTextoAES (string textoCifrado, string palabraPaso , string valorRGBSalt, string algoritmoEncriptacionHASH, int iteraciones, string vectorInicial, int tamanoClave) { try { byte[] InitialVectorBytes = Encoding.ASCII.GetBytes(vectorInicia l); byte[] saltValueBytes = Encoding.ASCII.GetBytes(valorRGBSalt); byte[] cipherTextBytes = Convert.FromBase64String(textoCifrado); PasswordDeriveBytes password = new PasswordDeriveBytes(palabraPaso, saltValueBytes, algoritmoEncriptacionHASH, iteraciones); byte[] keyBytes = password.GetBytes(tamanoClave / 8); RijndaelManaged symmetricKey = new RijndaelManaged(); symmetricKey.Mode = CipherMode.CBC; ICryptoTransform decryptor = symmetricKey.CreateDecryptor(keyByt es, InitialVectorBytes); MemoryStream memoryStream = new MemoryStream(cipherTextBytes); CryptoStream cryptoStream = new CryptoStream(memoryStream, decry ptor, CryptoStreamMode.Read); byte[] plainTextBytes = new byte[cipherTextBytes.Length]; int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, pl ainTextBytes.Length); memoryStream.Close(); cryptoStream.Close(); string textoDescifradoFinal = Encoding.UTF8.GetString(plainTextB ytes, 0, decryptedByteCount); return textoDescifradoFinal; } catch { return null; } } } }