Metro 风格应用中的 RSA 加密

我有公钥模数和公钥指数，我需要生成公钥并在 Metro 风格应用程序中加密数据。在 C# 中，我们有 RSAParameters 类，但我找不到任何适用于 Metro 风格应用程序的此类内容。

当我使用直接从证书接收的 base64 编码的公钥并尝试使用以下代码导入密钥时，我收到抛出异常 ASN1 bad tag value met 。 我认为这是由于数据格式无效造成的。

     //sample dummy key from certificate in base64encoded
     string key =   @"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";
       symmetricKeyAlgorithmProvider asymmAlg = AsymmetricKeyAlgorithmProvider.OpenAlgorithm("RSA_OAEP_SHA1");
       CryptographicKey publicKey = asymmAlg.ImportPublicKey(CryptographicBuffer.DecodeFromBase64String(key));
        string input64string ="encrypt this";
        IBuffer dataToEncrypt = CryptographicBuffer.DecodeFromBase64String(input64string);
        IBuffer encryptedData = CryptographicEngine.Encrypt(publicKey, dataToEncrypt, null);

Your key是公钥的模数部分，其长度为128。考虑从metro中的C#代码导出的标准密钥：

using System.Runtime.InteropServices.WindowsRuntime;
CryptographicKey standardKeyPair = provider.CreateKeyPair(1024);
byte[] standardKey = standardKeyPair.ExportPublicKey(CryptographicPublicKeyBlobType.Pkcs1RsaPublicKey).ToArray();

可以看到byte[] standardKey的长度是140，有7位前缀和5位尾部。我不知道原因，但我将额外的 12 位复制到已知密钥中，它有效。希望这对您有帮助：

public static IBuffer RsaEncrypt(this IBuffer dataToEncrypt, string publicKeyN)
{
    AsymmetricKeyAlgorithmProvider provider = AsymmetricKeyAlgorithmProvider.OpenAlgorithm(AsymmetricAlgorithmNames.RsaPkcs1);

    CryptographicKey standardKeyPair = provider.CreateKeyPair(1024);
    byte[] standardKey = standardKeyPair.ExportPublicKey(CryptographicPublicKeyBlobType.Pkcs1RsaPublicKey).ToArray();
    var data_n = CryptographicBuffer.DecodeFromBase64String(publicKeyN).ToArray();
    Array.Copy(data_n, 0, standardKey, 7, data_n.Length);
    var key = provider.ImportPublicKey(standardKey.AsBuffer(), CryptographicPublicKeyBlobType.Pkcs1RsaPublicKey);

    var result = CryptographicEngine.Encrypt(key, dataToEncrypt, null);
    return result;          
}