SymmetricKeyAlgorithmProvider Kelas

Definisi

Ruang nama:

Windows.Security.Cryptography.Core

Mewakili penyedia algoritma kunci konten. Untuk informasi selengkapnya, lihat Kunci kriptografi.

public ref class SymmetricKeyAlgorithmProvider sealed

/// [Windows.Foundation.Metadata.ContractVersion(Windows.Foundation.UniversalApiContract, 65536)]
/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
/// [Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
class SymmetricKeyAlgorithmProvider final

[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.Foundation.UniversalApiContract), 65536)]
[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
[Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
public sealed class SymmetricKeyAlgorithmProvider

Public NotInheritable Class SymmetricKeyAlgorithmProvider

Warisan

Object Platform::Object IInspectable SymmetricKeyAlgorithmProvider

Atribut

ContractVersionAttribute MarshalingBehaviorAttribute ThreadingAttribute

Persyaratan Windows

Rangkaian perangkat	Windows 10 (diperkenalkan dalam 10.0.10240.0)
API contract	Windows.Foundation.UniversalApiContract (diperkenalkan dalam v1.0)

Contoh

using Windows.Security.Cryptography;
using Windows.Security.Cryptography.Core;
using Windows.Storage.Streams;

namespace SampleSymmetricKeyAlgorithmProvider
{
    sealed partial class SymmKeyAlgProviderApp : Application
    {
        public SymmKeyAlgProviderApp()
        {
            // Initialize the application.
            this.InitializeComponent();

            // Initialize the encryption process.
            String strMsg = "1234567812345678";     // Data to encrypt.
            String strAlgName = SymmetricAlgorithmNames.AesCbc;
            UInt32 keyLength = 32;                  // Length of the key, in bytes
            BinaryStringEncoding encoding;          // Binary encoding value
            IBuffer iv;                             // Initialization vector
            CryptographicKey key;                   // Symmetric key

            // Encrypt a message.
            IBuffer buffEncrypted = this.SampleCipherEncryption(
                strMsg,
                strAlgName,
                keyLength,
                out encoding,
                out iv,
                out key);

            // Decrypt a message.
            this.SampleCipherDecryption(
                strAlgName,
                buffEncrypted,
                iv,
                encoding,
                key);
        }

        public IBuffer SampleCipherEncryption(
            String strMsg,
            String strAlgName,
            UInt32 keyLength,
            out BinaryStringEncoding encoding,
            out IBuffer iv,
            out CryptographicKey key)
        {
            // Initialize the initialization vector.
            iv = null;

            // Initialize the binary encoding value.
            encoding = BinaryStringEncoding.Utf8;

            // Create a buffer that contains the encoded message to be encrypted. 
            IBuffer buffMsg = CryptographicBuffer.ConvertStringToBinary(strMsg, encoding);

            // Open a symmetric algorithm provider for the specified algorithm. 
            SymmetricKeyAlgorithmProvider objAlg = SymmetricKeyAlgorithmProvider.OpenAlgorithm(strAlgName);

            // Demonstrate how to retrieve the name of the algorithm used.
            String strAlgNameUsed = objAlg.AlgorithmName;

            // Determine whether the message length is a multiple of the block length.
            // This is not necessary for PKCS #7 algorithms which automatically pad the
            // message to an appropriate length.
            if (!strAlgName.Contains("PKCS7"))
            {
               if ((buffMsg.Length % objAlg.BlockLength) != 0)
                {
                    throw new Exception("Message buffer length must be multiple of block length.");
                }
            }

            // Create a symmetric key.
            IBuffer keyMaterial = CryptographicBuffer.GenerateRandom(keyLength);
            key = objAlg.CreateSymmetricKey(keyMaterial);

            // CBC algorithms require an initialization vector. Here, a random
            // number is used for the vector.
            if (strAlgName.Contains("CBC"))
            {
                iv = CryptographicBuffer.GenerateRandom(objAlg.BlockLength);
            }

            // Encrypt the data and return.
            IBuffer buffEncrypt = CryptographicEngine.Encrypt(key, buffMsg, iv);
            return buffEncrypt;
        }

        public void SampleCipherDecryption(
            String strAlgName,
            IBuffer buffEncrypt,
            IBuffer iv,
            BinaryStringEncoding encoding,
            CryptographicKey key)
        {
            // Declare a buffer to contain the decrypted data.
            IBuffer buffDecrypted;

            // Open an symmetric algorithm provider for the specified algorithm. 
            SymmetricKeyAlgorithmProvider objAlg = SymmetricKeyAlgorithmProvider.OpenAlgorithm(strAlgName);

            // The input key must be securely shared between the sender of the encrypted message
            // and the recipient. The initialization vector must also be shared but does not
            // need to be shared in a secure manner. If the sender encodes a message string 
            // to a buffer, the binary encoding method must also be shared with the recipient.
            buffDecrypted = CryptographicEngine.Decrypt(key, buffEncrypt, iv);

            // Convert the decrypted buffer to a string (for display). If the sender created the
            // original message buffer from a string, the sender must tell the recipient what 
            // BinaryStringEncoding value was used. Here, BinaryStringEncoding.Utf8 is used to
            // convert the message to a buffer before encryption and to convert the decrypted
            // buffer back to the original plaintext.
            String strDecrypted = CryptographicBuffer.ConvertBinaryToString(encoding, buffDecrypted);
        }
    }
}

Keterangan

Anda membuat objek SymmetricKeyAlgorithmProvider dengan memanggil metode OpenAlgorithm statis dan menentukan salah satu nama algoritma berikut.

• Tidak ada padding:+ DES_CBC

• DES_ECB

• 3DES_CBC

• 3DES_ECB

• RC2_CBC

• RC2_ECB

• AES_CBC

• AES_ECB

• Mode padding blok PKCS#7:+ AES_CBC_PKCS7

• AES_ECB_PKCS7

• DES_CBC_PKCS7

• DES_ECB_PKCS7

• 3DES_CBC_PKCS7

• 3DES_ECB_PKCS7

• RC2_CBC_PKCS7

• RC2_ECB_PKCS7

• Mode terautentikasi (lihat kelas EncryptedAndAuthenticatedData ):+ AES_GCM

• AES_CCM

• Stream Cipher:+ RC4

Properti

AlgorithmName	Mendapatkan nama algoritma simetris terbuka.
BlockLength	Mendapatkan ukuran, dalam byte, dari blok sandi untuk algoritma terbuka.

Metode

CreateSymmetricKey(IBuffer)	Membuat kunci simetris.
OpenAlgorithm(String)	Membuat instans kelas SymmetricKeyAlgorithmProvider dan membuka algoritma yang ditentukan untuk digunakan.

Lihat juga

• AsymmetricKeyAlgorithmProvider
• CryptographicEngine
• CryptographicKey