Security class implements encryption and decryption under the. NET Framework.

 

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-->UsingSystem;
UsingSystem. Security. cryptography;
UsingSystem. IO;
UsingSystem. text;

/// 
///Security summary.
///Security class implements encryption and decryption under the. NET Framework.
///Copyright --
/// 

/*
Different keys are used for URL and account encryption. The URL encryption process is as follows:
EIP. Framework. Security objsecurity = new EIP. Framework. Security ();
Objsecurity. encryptquerystring (''string to be encrypted '');

Decryption: objsecurity. decryptquerystring (''passed parameter );
**/

Public   Class Security
{
String _ Querystringkey =   " Abcdefgh " ; // URL transmission parameter encryption key
String _ Passwordkey =   " Hgfedcba " ; // Password encryption key

Public Security ()
{
//
// Todo: add the constructor logic here
//
}

///  
/// Encrypted URL transmission string
///  
///  
///  
Public   String Encryptquerystring ( String Querystring)
{
Return Encrypt (querystring, _ querystringkey );
}

///  
/// Decrypts the string transmitted by the URL
///  
///  
///  
Public   String Decryptquerystring ( String Querystring)
{
Return Decrypt (querystring, _ querystringkey );
}

///  
/// Encrypted account password
///  
///  
///  
Public   String Encryptpassword ( String Password)
{
Return Encrypt (password, _ passwordkey );
}

///  
/// Decrypt account password
///  
///  
///  
Public   String Decryptpassword ( String Password)
{
Return Decrypt (password, _ passwordkey );
}

///  
/// Dec encryption process
///  
///  
///  
///  
Public   String Encrypt ( String Ptoencrypt, String Skey)
{
Descryptoserviceprovider des =   New Descryptoserviceprovider (); // Put the string in the byte array

Byte [] Inputbytearray = Encoding. Default. getbytes (ptoencrypt );
// Byte [] inputbytearray = encoding. Unicode. getbytes (ptoencrypt );

Des. Key = Asciiencoding. ASCII. getbytes (skey ); // Create the key and offset of the encryption object
Des. iv = Asciiencoding. ASCII. getbytes (skey ); // The getbytes method of the original article using the asciiencoding. ASCII Method
Memorystream MS =   New Memorystream (); // So that the password must be entered in English text
Cryptostream CS =   New Cryptostream (MS, Des. createencryptor (), cryptostreammode. Write );

CS. Write (inputbytearray,0, Inputbytearray. Length );
CS. flushfinalblock ();

Stringbuilder RET =   New Stringbuilder ();
Foreach ( Byte B In Ms. toarray ())
{
Ret. appendformat ( " {0: X2} " , B );
}
Ret. tostring ();
Return Ret. tostring ();
}

///  
/// Dec decryption process
///  
///  
///  
///  
Public   String Decrypt ( String Ptodecrypt, String Skey)
{
Descryptoserviceprovider des =   New Descryptoserviceprovider ();

Byte [] Inputbytearray =   New   Byte [Ptodecrypt. Length /   2 ];
For ( Int X =   0 ; X < Ptodecrypt. Length /   2 ; X ++ )
{
Int I = (Convert. toint32 (ptodecrypt. substring (x *   2 , 2 ), 16 ));
Inputbytearray [x] = ( Byte ) I;
}

Des. Key= Asciiencoding. ASCII. getbytes (skey ); // Establishes the key and offset of the encryption object. This value is important and cannot be modified.
Des. iv = Asciiencoding. ASCII. getbytes (skey );
Memorystream MS =   New Memorystream ();
Cryptostream CS =   New Cryptostream (MS, Des. createdecryptor (), cryptostreammode. Write );

CS. Write (inputbytearray,0, Inputbytearray. Length );
CS. flushfinalblock ();

Stringbuilder RET= NewStringbuilder ();//Create a stringbuild object. createdecrypt uses a stream object. The decrypted text must be converted to a stream object.

ReturnSystem. Text. encoding. Default. getstring (Ms. toarray ());
}

///  
/// Check whether the encrypted string is the same as the original one.
///  
///  
///  
///  
///  
Public   Bool Validatestring ( String Enstring, String Fostring, Int Mode)
{
Switch (Mode)
{
Default :
Case   1 :
If (Decrypt (enstring, _ querystringkey) = Fostring. tostring ())
{
Return   True ;
}
Else
{
Return   False ;
}
Case   2 :
If (Decrypt (enstring, _ passwordkey) = Fostring. tostring ())
{
Return   True ;
}
Else
{
Return   False ;
}
}
}
}