. Net (C #) cryptographic decryption of AES and Des

　　

<summary>
/// . NET Cryptographic decryption helper class
</summary>
public class Netcryptohelper
{
#region des implementations

<summary>
Des default key vector
</summary>
public static byte[] Desiv = {0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF};
<summary>
Des plus decryption key must be 8 bits
</summary>
Public Const string Deskey = "deskey8w";
<summary>
Get DES8 bit key
</summary>
<param name= "key" >des key string </param>
&LT;RETURNS&GT;DES8-bit key </returns>
Static byte[] Getdeskey (string key)
{
if (string. IsNullOrEmpty (Key))
{
throw new ArgumentNullException ("Key", "des key cannot be null");
}
if (key. Length > 8)
{
Key = key. Substring (0, 8);
}
if (key. Length < 8)
{
Less than 8 full complement
Key = key. PadRight (8, ' 0 ');
}
return Encoding.UTF8.GetBytes (key);
}
<summary>
DES encryption
</summary>
<param name= "Source" > Sources string </param>
<param name= "key" >des key, length must be 8 bits </param>
<param name= "IV" > Key vector </param>
<returns> string after encryption </returns>
public static string Encryptdes (string source, String key, byte[] IV)
{
using (DESCryptoServiceProvider Desprovider = new DESCryptoServiceProvider ())
{
byte[] Rgbkeys = Getdeskey (key),
Rgbivs = IV,
Inputbytearray = Encoding.UTF8.GetBytes (source);
using (MemoryStream MemoryStream = new MemoryStream ())
{
using (CryptoStream cryptostream = new CryptoStream (MemoryStream, Desprovider.createencryptor (RgbKeys, RgbIvs), CryptoStreamMode.Write))
{
Cryptostream.write (Inputbytearray, 0, inputbytearray.length);
Cryptostream.flushfinalblock ();
1. The first type of
Return convert.tobase64string (Memorystream.toarray ());

2. The second type of
StringBuilder result = new StringBuilder ();
foreach (Byte b in Memorystream.toarray ())
//{
Result. AppendFormat ("{0:x2}", b);
//}
return result. ToString ();
}
}
}
}
<summary>
Des decryption
</summary>
<param name= "Source" > Sources string </param>
<param name= "key" >des key, length must be 8 bits </param>
<param name= "IV" > Key vector </param>
<returns> decrypted String </returns>
public static string Decryptdes (string source, String key, byte[] IV)
{
using (DESCryptoServiceProvider Desprovider = new DESCryptoServiceProvider ())
{
byte[] Rgbkeys = Getdeskey (key),
Rgbivs = IV,
Inputbytearray = convert.frombase64string (source);
using (MemoryStream MemoryStream = new MemoryStream ())
{
using (CryptoStream cryptostream = new CryptoStream (MemoryStream, Desprovider.createdecryptor (RgbKeys, RgbIvs), CryptoStreamMode.Write))
{
Cryptostream.write (Inputbytearray, 0, inputbytearray.length);
Cryptostream.flushfinalblock ();
Return Encoding.UTF8.GetString (Memorystream.toarray ());
}
}
}
}

#endregion

#region AES Implementation

<summary>
AES decryption key must be 32 bits
</summary>
public static string Aeskey = "asekey32w";
<summary>
Get AES32 bit key
</summary>
<param name= "key" >aes key string </param>
&LT;RETURNS&GT;AES32-bit key </returns>
Static byte[] Getaeskey (string key)
{
if (string. IsNullOrEmpty (Key))
{
throw new ArgumentNullException ("Key", "AES key cannot be null");
}
if (key. Length < 32)
{
Less than 32 full complement
Key = key. PadRight (32, ' 0 ');
}
if (key. Length > 32)
{
Key = key. Substring (0, 32);
}
return Encoding.UTF8.GetBytes (key);
}
<summary>
AES Encryption
</summary>
<param name= "Source" > Sources string </param>
<param name= "key" >aes key, length must be 32 bits </param>
<returns> string after encryption </returns>
public static string Encryptaes (string source, string key)
{
using (Aescryptoserviceprovider Aesprovider = new Aescryptoserviceprovider ())
{
Aesprovider.key = Getaeskey (Key);
Aesprovider.mode = CIPHERMODE.ECB;
aesprovider.padding = PADDINGMODE.PKCS7;
using (ICryptoTransform cryptotransform = Aesprovider.createencryptor ())
{
byte[] Inputbuffers = Encoding.UTF8.GetBytes (source);
Byte[] results = cryptotransform.transformfinalblock (inputbuffers, 0, inputbuffers.length);
Aesprovider.clear ();
Aesprovider.dispose ();
Return convert.tobase64string (results, 0, results. Length);
}
}
}
<summary>
AES Decryption
</summary>
<param name= "Source" > Sources string </param>
<param name= "key" >aes key, length must be 32 bits </param>
<returns> decrypted String </returns>
public static string Decryptaes (string source, string key)
{
using (Aescryptoserviceprovider Aesprovider = new Aescryptoserviceprovider ())
{
Aesprovider.key = Getaeskey (Key);
Aesprovider.mode = CIPHERMODE.ECB;
aesprovider.padding = PADDINGMODE.PKCS7;
using (ICryptoTransform cryptotransform = Aesprovider.createdecryptor ())
{
byte[] Inputbuffers = convert.frombase64string (source);
Byte[] results = cryptotransform.transformfinalblock (inputbuffers, 0, inputbuffers.length);
Aesprovider.clear ();
return Encoding.UTF8.GetString (results);
}
}
}

#endregion
}

Class Program{ Static void Main(String[]Args) { StringPlainText= "Blog Park",EncryptString= Netcryptohelper.Encryptdes(PlainText, Netcryptohelper.Deskey, Netcryptohelper.Desiv); Console.WriteLine("String before des encryption: {0}",PlainText); Console.WriteLine("Des encrypted string: {0}",EncryptString); Console.WriteLine("Des decrypted string: {0}", Netcryptohelper.Decryptdes(EncryptString, Netcryptohelper.Deskey, Netcryptohelper.Desiv)); Console.WriteLine("-----------Split Line-----------"); Console.WriteLine("String before AES encryption: {0}",PlainText);EncryptString= Netcryptohelper.Encryptaes(PlainText, Netcryptohelper.Aeskey); Console.WriteLine ( "AES-encrypted string: {0}" , Encryptstring console. Writeline ( "AES Decrypted string: {0}" , netcryptohelper. Decryptaes (encryptstring, netcryptohelper. Aeskey console. Readkey}}          /span>                

. Net (C #) cryptographic decryption of AES and Des