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Metodo RC2.Create ()

 

Data di pubblicazione: novembre 2016

Crea un'istanza di un oggetto di crittografia per eseguire l'algoritmo RC2.

Spazio dei nomi:   System.Security.Cryptography
Assembly:  mscorlib (in mscorlib.dll)

public static RC2 Create()

Valore restituito

Type: System.Security.Cryptography.RC2

Istanza di un oggetto di crittografia.

Exception Condition
TargetInvocationException

L'algoritmo è stato usato con la modalità FIPS (Federal Information Processing Standards) abilitata, ma non è compatibile con FIPS.

Use this method to create an instance of the RC2 class that you can use to encrypt and decrypt data.

The following example shows how to create and use an RC2 object to encrypt and decrypt data in a file.

using System;
using System.Security.Cryptography;
using System.Text;
using System.IO;

class RC2Sample
{

    static void Main()
    {
        try
        {
            // Create a new RC2 object to generate a key
            // and initialization vector (IV).
            RC2 RC2alg = RC2.Create();

            // Create a string to encrypt.
            string sData = "Here is some data to encrypt.";
            string FileName = "CText.txt";

            // Encrypt text to a file using the file name, key, and IV.
            EncryptTextToFile(sData, FileName, RC2alg.Key, RC2alg.IV);

            // Decrypt the text from a file using the file name, key, and IV.
            string Final = DecryptTextFromFile(FileName, RC2alg.Key, RC2alg.IV);

            // Display the decrypted string to the console.
            Console.WriteLine(Final);
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }

    }

    public static void EncryptTextToFile(String Data, String FileName, byte[] Key, byte[] IV)
    {
        try
        {
            // Create or open the specified file.
            FileStream fStream = File.Open(FileName,FileMode.OpenOrCreate);

            // Create a new RC2 object.
            RC2 RC2alg = RC2.Create();

            // Create a CryptoStream using the FileStream 
            // and the passed key and initialization vector (IV).
            CryptoStream cStream = new CryptoStream(fStream, 
                RC2alg.CreateEncryptor(Key,IV), 
                CryptoStreamMode.Write); 

            // Create a StreamWriter using the CryptoStream.
            StreamWriter sWriter = new StreamWriter(cStream);

            // Write the data to the stream 
            // to encrypt it.
            sWriter.WriteLine(Data);

            // Close the streams and
            // close the file.
            sWriter.Close();
            cStream.Close();
            fStream.Close();
        }
        catch(CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
        }
        catch(UnauthorizedAccessException  e)
        {
            Console.WriteLine("A file error occurred: {0}", e.Message);
        }

    }

    public static string DecryptTextFromFile(String FileName, byte[] Key, byte[] IV)
    {
        try
        {
            // Create or open the specified file. 
            FileStream fStream = File.Open(FileName, FileMode.OpenOrCreate);

            // Create a new RC2 object.
            RC2 RC2alg = RC2.Create();

            // Create a CryptoStream using the FileStream 
            // and the passed key and initialization vector (IV).
            CryptoStream cStream = new CryptoStream(fStream, 
                RC2alg.CreateDecryptor(Key,IV), 
                CryptoStreamMode.Read); 

            // Create a StreamReader using the CryptoStream.
            StreamReader sReader = new StreamReader(cStream);

            // Read the data from the stream 
            // to decrypt it.
            string val = sReader.ReadLine();

            // Close the streams and
            // close the file.
            sReader.Close();
            cStream.Close();
            fStream.Close();

            // Return the string. 
            return val;
        }
        catch(CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
            return null;
        }
        catch(UnauthorizedAccessException  e)
        {
            Console.WriteLine("A file error occurred: {0}", e.Message);
            return null;
        }
    }
}

The following example shows how to create and use an RC2 object to encrypt and decrypt data in memory.

using System;
using System.Security.Cryptography;
using System.Text;
using System.IO;

class RC2Sample
{
    static void Main()
    {
        try
        {
            // Create a new RC2 object to generate a key
            // and initialization vector (IV).
            RC2 RC2alg = RC2.Create();

            // Create a string to encrypt.
            string sData = "Here is some data to encrypt.";

            // Encrypt the string to an in-memory buffer.
            byte[] Data = EncryptTextToMemory(sData, RC2alg.Key, RC2alg.IV);

            // Decrypt the buffer back to a string.
            string Final = DecryptTextFromMemory(Data, RC2alg.Key, RC2alg.IV);

            // Display the decrypted string to the console.
            Console.WriteLine(Final);
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }

    }

    public static byte[] EncryptTextToMemory(string Data,  byte[] Key, byte[] IV)
    {
        try
        {
            // Create a MemoryStream.
            MemoryStream mStream = new MemoryStream();

            // Create a new RC2 object.
            RC2 RC2alg = RC2.Create();

            // Create a CryptoStream using the MemoryStream 
            // and the passed key and initialization vector (IV).
            CryptoStream cStream = new CryptoStream(mStream, 
                RC2alg.CreateEncryptor(Key, IV), 
                CryptoStreamMode.Write);

            // Convert the passed string to a byte array.
            byte[] toEncrypt = new ASCIIEncoding().GetBytes(Data);

            // Write the byte array to the crypto stream and flush it.
            cStream.Write(toEncrypt, 0, toEncrypt.Length);
            cStream.FlushFinalBlock();

            // Get an array of bytes from the 
            // MemoryStream that holds the 
            // encrypted data.
            byte[] ret = mStream.ToArray();

            // Close the streams.
            cStream.Close();
            mStream.Close();

            // Return the encrypted buffer.
            return ret;
        }
        catch(CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
            return null;
        }

    }

    public static string DecryptTextFromMemory(byte[] Data,  byte[] Key, byte[] IV)
    {
        try
        {
            // Create a new MemoryStream using the passed 
            // array of encrypted data.
            MemoryStream msDecrypt = new MemoryStream(Data);

            // Create a new RC2 object.
            RC2 RC2alg = RC2.Create();

            // Create a CryptoStream using the MemoryStream 
            // and the passed key and initialization vector (IV).
            CryptoStream csDecrypt = new CryptoStream(msDecrypt, 
                RC2alg.CreateDecryptor(Key, IV), 
                CryptoStreamMode.Read);

            // Create buffer to hold the decrypted data.
            byte[] fromEncrypt = new byte[Data.Length];

            // Read the decrypted data out of the crypto stream
            // and place it into the temporary buffer.
            csDecrypt.Read(fromEncrypt, 0, fromEncrypt.Length);

            //Convert the buffer into a string and return it.
            return new ASCIIEncoding().GetString(fromEncrypt);
        }
        catch(CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
            return null;
        }
    }
}

.NET Framework
Disponibile da 1.1
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