KeyDerivationAlgorithmProvider Classe

Définition

public ref class KeyDerivationAlgorithmProvider 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 KeyDerivationAlgorithmProvider 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 KeyDerivationAlgorithmProvider

Public NotInheritable Class KeyDerivationAlgorithmProvider

Héritage

Object Platform::Object IInspectable KeyDerivationAlgorithmProvider

Attributs

ContractVersionAttribute MarshalingBehaviorAttribute ThreadingAttribute

Configuration requise pour Windows

Exemples

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

namespace SampleKeyDerivationAlgorithm
{
    sealed partial class SampleKeyDerivationProviderApp : Application
    {
        public SampleKeyDerivationProviderApp()
        {
            // Initialize the Application.
            this.InitializeComponent();

            // Derive key material from a password-based key derivation function.
            String strKdfAlgName = KeyDerivationAlgorithmNames.Pbkdf2Sha256;
            UInt32 targetKeySize = 32;
            UInt32 iterationCount = 10000;
            IBuffer buffKeyMatl = this.SampleDeriveKeyMaterialPbkdf(
                strKdfAlgName,
                targetKeySize,
                iterationCount);

            // Create a key.
            CryptographicKey key = this.SampleCreateKDFKey(
                strKdfAlgName,
                buffKeyMatl);
        }

        public IBuffer SampleDeriveKeyMaterialPbkdf(
            String strAlgName,
            UInt32 targetKeySize,
            UInt32 iterationCount)
        {

            // Open the specified algorithm.
            KeyDerivationAlgorithmProvider objKdfProv = KeyDerivationAlgorithmProvider.OpenAlgorithm(strAlgName);

            // Demonstrate how to retrieve the algorithm name.
            String strAlgUsed = objKdfProv.AlgorithmName;

            // Create a buffer that contains the secret used during derivation.
            String strSecret = "MyPassword";
            IBuffer buffSecret = CryptographicBuffer.ConvertStringToBinary(strSecret, BinaryStringEncoding.Utf8);

            // Create a random salt value.
            IBuffer buffSalt = CryptographicBuffer.GenerateRandom(32);

            // Create the derivation parameters.
            KeyDerivationParameters pbkdf2Params = KeyDerivationParameters.BuildForPbkdf2(buffSalt, iterationCount);

            // Create a key from the secret value.
            CryptographicKey keyOriginal = objKdfProv.CreateKey(buffSecret);

            // Derive a key based on the original key and the derivation parameters.
            IBuffer keyMaterial = CryptographicEngine.DeriveKeyMaterial(
                keyOriginal,
                pbkdf2Params,
                targetKeySize);

            // Demonstrate checking the iteration count.
            UInt32 iterationCountOut = pbkdf2Params.IterationCount;

            // Demonstrate returning the derivation parameters to a buffer.
            IBuffer buffParams = pbkdf2Params.KdfGenericBinary;

            // return the KDF key material.
            return keyMaterial;
        }

        public CryptographicKey SampleCreateKDFKey(
            String strAlgName,
            IBuffer buffKeyMaterial)
        {
            // Create a KeyDerivationAlgorithmProvider object and open the specified algorithm.
            KeyDerivationAlgorithmProvider objKdfAlgProv = KeyDerivationAlgorithmProvider.OpenAlgorithm(strAlgName);

            // Create a key by using the KDF parameters.
            CryptographicKey key = objKdfAlgProv.CreateKey(buffKeyMaterial);

            return key;
        }
    }
}

Remarques

Lorsque plusieurs parties partagent une clé symétrique secrète, il est souvent nécessaire de dériver des clés supplémentaires pour les utiliser dans des opérations de chiffrement. Il est également souvent nécessaire pour un tiers de confiance de dériver des clés de chiffrement distinctes à partir d’une clé master unique. Les fonctions de dérivation de clé sont utilisées pour dériver ces clés supplémentaires.

Vous pouvez utiliser la méthode DeriveKeyMaterial statique dans la classe CryptographicEngine et les méthodes suivantes de la classe KeyDerivationParameters pour dériver une clé.

Vous créez un objet KeyDerivationAlgorithmProvider en appelant la méthode OpenAlgorithm statique.

Propriétés

Méthodes

S’applique à

Voir aussi

• CryptographicEngine
• KeyDerivationParameters