wcf – Windows 8 Metro RSA加密：AsymmetricKeyAlgorithmProvid

我试图在Win 8 Metro应用程序和RESTful WCF服务之间传递一些加密数据.最初Metro应用程序请求公钥,WCF服务将其作为原始流返回,以避免任何讨厌的格式问题. Base 64编码的公钥在metro应用程序中解码为字节数组.这是问题发生的地方.当我试图调用AsymmetricKeyAlgorithmProvider.ImportPublicKey时,我收到错误“ASN1错误标记值已满足”.

我使用RSA PKCS1进行加密.这是相关代码：

WCF服务

string keyName = "This is passed in via a parameter";
     var key = !CngKey.Exists(keyName) ? CngKey.Create(CngAlgorithm2.Rsa,keyName) : CngKey.Open(keyName);

     // Create the RSA container to get keys and then dispose
     using (var rsaCng = new RSACng(key) { EncryptionPaddingMode = AsymmetricPaddingMode.Pkcs1,KeySize = 2048 })
     {
        byte[] publicBlob = rsaCng.Key.Export(CngKeyBlobFormat.GenericPublicBlob);
        publicKey = Convert.ToBase64String(publicBlob);
     }

Metro App

public static string Encrypt(IBuffer dataBuffer,string publicKeyString)
  {
     var asymmAlg = AsymmetricKeyAlgorithmProvider.OpenAlgorithm(AsymmetricAlgorithmNames.RsaPkcs1);
     // The next line fails with ASN1 bad tag value met
     var publicKey = asymmAlg.ImportPublicKey(CryptographicBuffer.DecodeFromBase64String(publicKeyString),CryptographicPublicKeyBlobType.Pkcs1RsaPublicKey);

     var encryptedData = CryptographicEngine.Encrypt(publicKey,dataBuffer,null);
     return CryptographicBuffer.EncodeToBase64String(encryptedData);
  }

编辑1：以下更多信息

从WCF服务从2048位密钥对导出公钥会产生283位长的密钥blob,而从Metro应用程序导出相同类型的公钥只有270位.当我导入Metro生成的公钥时,它成功.知道为什么WCF服务在其公钥上有13个额外位吗？我认为那些额外的13位导致失败.

以下是产生较短公钥blob的Metro代码：

var provider = AsymmetricKeyAlgorithmProvider.OpenAlgorithm(AsymmetricAlgorithmNames.RsaPkcs1);
CryptographicKey standardKeyPair = provider.CreateKeyPair(2048);
byte[] standardKey = standardKeyPair.ExportPublicKey(CryptographicPublicKeyBlobType.Pkcs1RsaPublicKey).ToArray();

public static string Encrypt(IBuffer dataBuffer,string publicKeyString)
{
    var asymmAlg = AsymmetricKeyAlgorithmProvider.OpenAlgorithm(AsymmetricAlgorithmNames.RsaPkcs1);
    // The next line fails with ASN1 bad tag value met
    var publicKey = asymmAlg.ImportPublicKey(CryptographicBuffer.DecodeFromBase64String(publicKeyString),CryptographicPublicKeyBlobType.BCryptPublicKey);

    var encryptedData = CryptographicEngine.Encrypt(publicKey,null);
    return CryptographicBuffer.EncodeToBase64String(encryptedData);
}