Question

我有公钥模数和公钥指数，我需要在metro风格的应用程序中生成公钥并加密数据。在c＃中我们有RSAParameters类，但我找不到类似地铁样式的应用程序。

当我使用从证书直接接收的base64encoded公钥并尝试使用以下代码导入密钥时，我得到异常抛出的ASN1错误标记值。我认为这是由于数据格式无效。

     //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);

Answer 1

您的key是公钥的模数部分，其长度为128.考虑从地铁中的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();

你可以看到byte [] standardKey的长度是140，它有7位前缀和5位尾。我不知道原因，但我将额外的12位复制到已知密钥，它可以工作。希望这可以帮到你：

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;          
}

Answer 2

这应该按照你的要求行事：

public static IBuffer RsaEncrypt(byte[] modulus, byte[] exponent, IBuffer data)
{
  var rsa = AsymmetricKeyAlgorithmProvider.OpenAlgorithm(AsymmetricAlgorithmNames.RsaOaepSha1);
  var keyBlob = modulus.Concat(exponent).ToArray().AsBuffer();
  var publicKey = rsa.ImportPublicKey(keyBlob, CryptographicPublicKeyBlobType.Pkcs1RsaPublicKey);
  return CryptographicEngine.Encrypt(publicKey, data, null);
}

当然，如果需要，你仍然可以使用base64字符串作为输入/输出，但是你已经知道如何做到这一点。：）

如果你深入到RFC3447的第61页，你会发现公钥格式结构只是模数后跟指数，这就是我连接它们的原因。

地铁式应用中的RSA加密

2 个答案: