C # Simple Encryption class Instance _c# tutorial

Copy Code code as follows:

public static Class Encryptanddecrypt
{
Encryption
public static string Encrypt (String input)
{
Salt value
String saltvalue = "Saltvalue";
Password value
String pwdvalue = "Pwdvalue";
byte[] data = System.Text.UTF8Encoding.UTF8.GetBytes (input);
byte[] Salt = System.Text.UTF8Encoding.UTF8.GetBytes (saltvalue);
Aesmanaged-Advanced Encryption Standard (AES) symmetric algorithm management class
System.Security.Cryptography.AesManaged AES = new System.Security.Cryptography.AesManaged ();
Rfc2898derivebytes-Cryptography based Key derivation (PBKDF2-a password-based key derivation function) by using a HMACSHA1 pseudo-random number generator
Derive keys by password and salt
System.Security.Cryptography.Rfc2898DeriveBytes RFC = new System.Security.Cryptography.Rfc2898DeriveBytes (pwdvalue , salt);
/**/
/*
* Aesmanaged.blocksize-Block size for cryptographic operations (units: bit)
* aesmanaged.legalblocksizes-Symmetric algorithm supported block size (unit: bit)
* Aesmanaged.keysize-Symmetric algorithm key size (unit: bit)
* aesmanaged.legalkeysizes-the key size supported by the symmetric algorithm (unit: bit)
* Aesmanaged.key-The key of the symmetric algorithm
* AESMANAGED.IV-the key size of the symmetric algorithm
* Rfc2898derivebytes.getbytes (the number of pseudo-random key bytes to be generated by int)-Generate key
*/
Aes. BlockSize = AES. Legalblocksizes[0]. MaxSize;
Aes. KeySize = AES. Legalkeysizes[0]. MaxSize;
Aes. Key = RfC. GetBytes (AES. KEYSIZE/8);
AES.IV = RfC. GetBytes (AES. BLOCKSIZE/8);
Creates a symmetric cryptographic object with the current Key property and initialization vector IV
System.Security.Cryptography.ICryptoTransform encrypttransform = AES. CreateEncryptor ();
The output stream after encryption
System.IO.MemoryStream EncryptStream = new System.IO.MemoryStream ();
Connect the encrypted target stream (EncryptStream) to the Cryptographic transformation (encrypttransform)
System.Security.Cryptography.CryptoStream encryptor = new System.Security.Cryptography.CryptoStream
(EncryptStream, Encrypttransform, System.Security.Cryptography.CryptoStreamMode.Write);
Writes a sequence of bytes to the current CryptoStream (the process of completing the encryption)
Encryptor. Write (data, 0, data. Length);
Encryptor. Close ();
Converts the resulting stream to an array of bytes, which is then converted to a string using BASE64 encoding
String encryptedstring = Convert.tobase64string (Encryptstream.toarray ());
return encryptedstring;
}


#region Silverlight Password Decryption
/**/
<summary>
Decrypting data
</summary>
<param name= "Input" > Encrypted string </param>
<returns> the string before encryption </returns>
public static string Decrypt (String input)
{
Salt value (consistent with the value set when encrypting)
String saltvalue = "Saltvalue";
Password value (consistent with the value set when encrypting)
String pwdvalue = "Pwdvalue";
byte[] encryptbytes = convert.frombase64string (input);
byte[] Salt = Encoding.UTF8.GetBytes (saltvalue);
System.Security.Cryptography.AesManaged AES = new System.Security.Cryptography.AesManaged ();
System.Security.Cryptography.Rfc2898DeriveBytes RFC = new System.Security.Cryptography.Rfc2898DeriveBytes (pwdvalue , salt);
Aes. BlockSize = AES. Legalblocksizes[0]. MaxSize;
Aes. KeySize = AES. Legalkeysizes[0]. MaxSize;
Aes. Key = RfC. GetBytes (AES. KEYSIZE/8);
AES.IV = RfC. GetBytes (AES. BLOCKSIZE/8);
Creates a symmetric decryption object with the current Key property and initialization vector IV
System.Security.Cryptography.ICryptoTransform decrypttransform = AES. CreateDecryptor ();
Post-decryption output stream
MemoryStream decryptstream = new MemoryStream ();
Connect the decrypted target stream (Decryptstream) to the decryption Transformation (decrypttransform)
System.Security.Cryptography.CryptoStream decryptor = new System.Security.Cryptography.CryptoStream (
Decryptstream, Decrypttransform, System.Security.Cryptography.CryptoStreamMode.Write);
Writes a sequence of bytes to the current CryptoStream (completing the decryption process)
Decryptor. Write (encryptbytes, 0, encryptbytes.length);
Decryptor. Close ();
Converts the resulting stream to a string
byte[] decryptbytes = Decryptstream.toarray ();
String decryptedstring = UTF8Encoding.UTF8.GetString (decryptbytes, 0, decryptbytes.length);
return decryptedstring;
}
#endregion
}