KeyDerivationParameters.BuildForSP800108(IBuffer, IBuffer) 方法

定义

命名空间:

Windows.Security.Cryptography.Core

创建 KeyDerivationParameters 对象，用于计数器模式、基于哈希的消息身份验证代码 (HMAC) 密钥派生函数。

public:
 static KeyDerivationParameters ^ BuildForSP800108(IBuffer ^ label, IBuffer ^ context);

 static KeyDerivationParameters BuildForSP800108(IBuffer const& label, IBuffer const& context);

public static KeyDerivationParameters BuildForSP800108(IBuffer label, IBuffer context);

function buildForSP800108(label, context)

Public Shared Function BuildForSP800108 (label As IBuffer, context As IBuffer) As KeyDerivationParameters

参数

label

IBuffer

指定派生密钥材料的用途的缓冲区。

context

IBuffer

指定与派生的密钥材料相关的信息的缓冲区。 例如，上下文可以标识派生密钥材料的参与方，还可以识别派生双方已知的 nonce。

返回

KeyDerivationParameters

指在密钥派生期间使用的参数。

示例

public void SampleDeriveFromSP800108()
{
    // Create a string that contains the algorithm name.
    String strAlgName = KeyDerivationAlgorithmNames.Sp800108CtrHmacSha256;

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

    // Specify the requested size, in bytes, of the derived key. 
    UInt32 targetSize = 32;

    // Create a buffer that contains the label value.
    String strPurpose = "Purpose";
    IBuffer buffLabel = CryptographicBuffer.ConvertStringToBinary(strPurpose, BinaryStringEncoding.Utf8);

    // Create a buffer that contains the context value.
    byte[] Nonce = { 1, 1, 0, 0, 0, 0, 0, 0};
    IBuffer buffContext = CryptographicBuffer.CreateFromByteArray(Nonce);

    // Create the derivation parameters.
    KeyDerivationParameters kdf800108Params = KeyDerivationParameters.BuildForSP800108(buffLabel, buffContext);

    // Create a secret value.
    IBuffer buffSecret = CryptographicBuffer.GenerateRandom(32);

    // 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 keyDerived = CryptographicEngine.DeriveKeyMaterial(
        keyOriginal,
        kdf800108Params,
        targetSize);

    // Encode the key to a hexadecimal value (for display)
    String strKeyHex = CryptographicBuffer.EncodeToHexString(keyDerived);
}

注解

可以将以下算法名称与 OpenAlgorithm 函数一起使用，以打开 SP800108 KDF 算法提供程序：

• KeyDerivationAlgorithmNames.Sp800108CtrHmacMd5
• KeyDerivationAlgorithmNames.Sp800108CtrHmacSha1
• KeyDerivationAlgorithmNames.Sp800108CtrHmacSha256
• KeyDerivationAlgorithmNames.Sp800108CtrHmacSha384
• KeyDerivationAlgorithmNames.Sp800108CtrHmacSha512