"William Stacey [MVP]" wrote:

> I put methods like these in my Utils class. Easy way to encrypt strings or
> byte[]:
>
> /// <summary>
> /// Use AES to encrypt data string. The output string is the
> encrypted bytes as a base64 string.
> /// The same password must be used to decrypt the string.
> /// </summary>
> /// <param name="data">Clear string to encrypt.</param>
> /// <param name="password">Password used to encrypt the
> string.</param>
> /// <returns>Encrypted result as Base64 string.</returns>
> public static string EncryptData(string data, string password)
> {
> if ( data == null )
> throw new ArgumentNullException("data");
> if ( password == null )
> throw new ArgumentNullException("password");
>
> byte[] encBytes = EncryptData(Encoding.UTF8.GetBytes(data),
> password, PaddingMode.ISO10126);
> return Convert.ToBase64String(encBytes);
> }
>
> /// <summary>
> /// Decrypt the data string to the original string. The data must
> be the base64 string
> /// returned from the EncryptData method.
> /// </summary>
> /// <param name="data">Encrypted data generated from EncryptData
> method.</param>
> /// <param name="password">Password used to decrypt the
> string.</param>
> /// <returns>Decrypted string.</returns>
> public static string DecryptData(string data, string password)
> {
> if ( data == null )
> throw new ArgumentNullException("data");
> if ( password == null )
> throw new ArgumentNullException("password");
>
> byte[] encBytes = Convert.FromBase64String(data);
> byte[] decBytes = DecryptData(encBytes, password,
> PaddingMode.ISO10126);
> return Encoding.UTF8.GetString(decBytes);
> }
>
> public static byte[] EncryptData(byte[] data, string password,
> PaddingMode paddingMode)
> {
> if ( data == null || data.Length == 0 )
> throw new ArgumentNullException("data");
> if ( password == null )
> throw new ArgumentNullException("password");
>
> PasswordDeriveBytes pdb = new PasswordDeriveBytes(password,
> Encoding.UTF8.GetBytes("Salt"));
> RijndaelManaged rm = new RijndaelManaged();
> rm.Padding = paddingMode;
> ICryptoTransform encryptor =
> rm.CreateEncryptor(pdb.GetBytes(16), pdb.GetBytes(16));
>
> using ( MemoryStream msEncrypt = new MemoryStream() )
> using ( CryptoStream encStream = new CryptoStream(msEncrypt,
> encryptor, CryptoStreamMode.Write) )
> {
> encStream.Write(data, 0, data.Length);
> encStream.FlushFinalBlock();
> return msEncrypt.ToArray();
> }
> }
>
> public static byte[] DecryptData(byte[] data, string password,
> PaddingMode paddingMode)
> {
> if ( data == null || data.Length == 0 )
> throw new ArgumentNullException("data");
> if ( password == null )
> throw new ArgumentNullException("password");
>
> PasswordDeriveBytes pdb = new PasswordDeriveBytes(password,
> Encoding.UTF8.GetBytes("Salt"));
> RijndaelManaged rm = new RijndaelManaged();
> rm.Padding = paddingMode;
> ICryptoTransform decryptor =
> rm.CreateDecryptor(pdb.GetBytes(16), pdb.GetBytes(16));
>
> using ( MemoryStream msDecrypt = new MemoryStream(data) )
> using ( CryptoStream csDecrypt = new CryptoStream(msDecrypt,
> decryptor, CryptoStreamMode.Read) )
> {
> // Decrypted bytes will always be less then encrypted bytes,
> so len of encrypted data will be big enouph for buffer.
> byte[] fromEncrypt = new byte[data.Length];
>
> // Read as many bytes as possible.
> int read = csDecrypt.Read(fromEncrypt, 0,
> fromEncrypt.Length);
> if ( read < fromEncrypt.Length )
> {
> // Return a byte array of proper size.
> byte[] clearBytes = new byte[read];
> Buffer.BlockCopy(fromEncrypt, 0, clearBytes, 0, read);
> return clearBytes;
> }
> return fromEncrypt;
> }
> }
>
> --
> William Stacey [MVP]
>
> "Patrick" <questions@newsgroup.nospam> wrote in message
> news:2863A9DC-B695-4F8A-83C8-131A2B8723AD@microsoft.com...
> >I tried using the "Crytography Application Block Quick Start" to encrypt
> > (getting it the App.Config to point to my own
> > securityCryptographyconfiguration.config) to encrypt the password into
> > something like
> > XVgnl8i//tBn4t3QGMl02TDtqCtMN/0ER/LKe1Burvy/oODQ7N1U9asm2jlOyqUx
> >
> > I tried to decrypt it in as follows:
> > String password = System.Text.Encoding.Unicode.GetString(
> > Cryptographer.DecryptSymmetric("symprovider",
> > System.Text.Encoding.Unicode.GetBytes
> > (ConfigurationSettings.AppSettings["ADQuerySysUserPassword"])));
> >
> > Unfortunately:
> > the code throws the following exception:
> > ystem.Security.Cryptography.CryptographicException: PKCS7 padding is
> > invalid
> > and cannot be removed.
> > at
> > System.Security.Cryptography.RijndaelManagedTransform.TransformFinalBlock(Byte[]
> > inputBuffer, Int32 inputOffset, Int32 inputCount)
> > at System.Security.Cryptography.CryptoStream.FlushFinalBlock()
> > at System.Security.Cryptography.CryptoStream.Close()
> > at
> > Microsoft.Practices.EnterpriseLibrary.Common.Cryptography.SymmetricCryptographer.Transform(ICryptoTransform
> > transform, Byte[] buffer)
> > at
> > Microsoft.Practices.EnterpriseLibrary.Common.Cryptography.SymmetricCryptographer.Decrypt(Byte[]
> > encryptedText)
> > at
> > Microsoft.Practices.EnterpriseLibrary.Security.Cryptography.SymmetricAlgorithmProvider.Decrypt(Byte[]
> > ciphertext)
> > at
> > Microsoft.Practices.EnterpriseLibrary.Security.Cryptography.Cryptographer.DecryptSymmetric(String
> > symmetricInstance, Byte[] ciphertext, ConfigurationContext context)
> >
> > Why? and how do I resolve?
> >
> > "Patrick" wrote:
> >
> >> The Data EDRA is execellent in allowing Connection String to be
> >> encrypted,