SHA512withRSA Unterschrift Verifikation in .Net

Question

Ich habe eine "SHA512withRSA" Signatur, die Daten, die signiert wurden, und einen öffentlichen Schlüssel (in base64 Form), der mir von einer dritten Partei gesendet wurde. Ich muss überprüfen, ob die Signatur für die angegebenen Daten korrekt ist und den öffentlichen Schlüssel verwendet.

Grundlegende Frage ist, wie überprüfe ich dies in. Net (vorzugsweise C# -Code)?

Ist dies nur mit dem .Net-Framework möglich (es scheint nicht, es scheint, RSACryptoServiceProvider ist die relevante Klasse, aber es unterstützt nur SHA1 als Signieralgorithmus)?

Wenn nicht, mit welchen Bibliotheken kann ich das erreichen? Ich habe versucht, BouncyCastle, aber ich kann keine Dokumentation finden, die erklärt, wie man das deutlich macht. In fast allen Dokumenten geht es um den Umgang mit Zertifikaten, und ich habe keine Zertifikate.

Edit: Neues Codebeispiel (immer noch nicht)

using System; 
using System.Collections.Generic; 
using System.Diagnostics; 
using System.IO; 
using System.Linq; 
using System.Security.Cryptography; 
using System.Text; 
using System.Threading.Tasks; 

namespace SignatureVerificationTest 
{ 
    class Program 
    { 
     static void Main(string[] args) 
     { 
      var t = DoWorkAsync(); 
      Console.ReadLine(); 
     } 

     public static async Task DoWorkAsync() 
     { 
      var rawNotificationData = "merchantOrderId=e7ea4e4c-7ffa-4b19-8af9-ad875c493620&status=AUTHORISED&signature=hgvtCb6RjmhtumXTNuARW8fotZVoIJ%2FAaqXEow1pxA0Ic5afe0j2lGHO%2F6Q7rnPXqd728mMsmkjQSyxGDho7imxYGHEyEudt%2B%2FThOboAj%2FhePNLNfCeJR7DS7LIzO7SCTDkkTHZ%2F5sD5JhBATY3EFADrLnzzlF445mNRP%2Bv2vi3ogVC5k3oYfPCSmvOzd8DFUp6E6cwZelBGQjRHwVJf07%2B8x4esYxW%2FJii3z6quXzaKpImLFt3jaDTe109uwTwsv8bRBh%2F%2FSjFlHPaEr5QTAjTDA0IrMP6OggGTDkukW8sr7PUmQoq%2B4%2FLEIlHqXbuwZgJ2zr7fN75CcwWaj6FHfdiVvmeKGshO11DnHX7rN%2FTU36z7D7jRp%2Fykd4q409MorZUfZspHuXp2XRXo1732OZKRdYkX73eDphFKQUbmhGCf9wQq3xxxlw6Qr3ClTAi8SbOeY8IQIul%2Bp3x0X5G%2FiJmtiMcHMErxxCx2Y84OozrbvMEQP8qzY4FLUuV%2BKv9oragcXfDvpkJ4EAAqZPufXGZ3zCyk5yBJEXy6kqZ7ht16bpuD0aQMBlq2eTyQCOgtRvOPCFJYwCVJ8z43xQShffKa9Tj7gSgPE9LfvD3%2Ba4NdEh0Hg5yV7A7wABLySC%2F3thXvxVfVthNJEfdHZPhpAN2i3C5sql09R27k5SEV96c%3D"; 

      //Find the signature in the data, and url decode the value 
      var x = rawNotificationData.Split(new char[] { '&' }); 

      string notificationSignature = null; 
      foreach (var kvp in x) 
      { 
       var parts = kvp.Split(new char[] { '=' }); 
       if (parts[0] == "signature") 
       { 
        notificationSignature = Uri.UnescapeDataString(parts[1]); 
        break; 
       } 
      } 

      // Get the portion of the string that was signed 
      // Should be; 
      // merchantOrderId=e7ea4e4c-7ffa-4b19-8af9-ad875c493620&status=AUTHORISED 
      var signedData = rawNotificationData.Substring(0, rawNotificationData.IndexOf("&signature=", StringComparison.OrdinalIgnoreCase)); 


      //Define the public key (base 64 encoded string) 
      var publicKey = @"MIICIjANBgkqhkiG9w0BAQEFAAOCAg8AMIICCgKCAgEAv3kDhkB2yHn/4N1KtNsm 
8IuWuqfnOIDxOnR2txELEtKL1YqSTiAtoBHWfvGg2OMN1gu0/owecT7d9+TnXx7M 
NE4CGp3UOLkdTzRifDMrMh5T9WVvyKfV4Chnv/tkmK7BMSe+yS4T+3IQVBv0zFKu 
Hm9Y8Zicc5sIkTRdpgeg1wbYZkbKA5qZcYkKUKpWHKmWVMyIqqhwAcKFA9dc0j8f 
h6EM3JWQhFOFkXngUHX4O+L2mJ7rnYsMZzujoK3fNk/HIHYtJiZbkbEOzlDGhzp0 
ZackirqZ2iqPRSgZsVcyqTthNiYxjkOvB5AYb/Ww+3T/UQ2zaB0ac7dgLKrq8BL5 
HpVke93F4kQQ6M1BmIWfLiQt3FLRX+LxkcNC5q1SaPW8D/7lnYACM0JErrpA8/Dc 
7U7Th6R8Wk99V8O0FN6+t9gr3lwG99Hw7AykstlPWMdFDch+ljM4JGf/hvxcZDlp 
ACSRPf1BXNON1E6WMofyAXNSsuQ3kG/go0f5pzix+K/484y4PPKizbWTGWElK9sJ 
d2jDFEGG5iCoFzJNLvEvuvzHHhP+cM5y7LTX7D0B8LPdj1kIEboTAIfdhQ1IVVYa 
mSo7WTB/sHgxGk9+8K3EboGAzSmgIqlLrMZob1h8/32LsVSxKhgxs01tGotB7rJO 
MmwP7rPHQjvq0NoPMTFPd+ECAwEAAQ=="; 

      // Decode the base64 key into raw bytes 
      // (Decodes to 550 bytes) 
      var rawKey = Convert.FromBase64String(publicKey); 

      //Create an RSA crypto provider instance initialised with the key 
      //Decodes to a 512 byte modulus and 3 (1, 0, 1) byte exponent 
      using (var rsa = CreateRsa(rawKey)) 
      { 
       bool signatureVerified = rsa.VerifyData 
       (
        System.Text.UTF8Encoding.UTF8.GetBytes(signedData), 
        CryptoConfig.MapNameToOID("SHA512"), 
        Convert.FromBase64String(notificationSignature) 
       ); 

       //Fail if the signature didn't verify 
       Debug.Assert(signatureVerified, "Signature did not verify."); 
      } 
     } 

     private static readonly byte[] SeqOID = { 0x30, 0x0D, 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01, 0x05, 0x00 }; 

     private static RSACryptoServiceProvider CreateRsa(byte[] publicKey) 
     { 
      /* 

      This code parses the publickey bytes to extract the relevant bits of the public key, the initialises 
      the rsa crypto provider with the key. 
      Taken from "CreateRsa" below is modified from http://www.jensign.com/JavaScience/dotnet/pempublic/ 

      Original license below applies. 

      Copyright(c) 2006 - 2014 JavaScience Consulting, Michel Gallant 

      Permission is hereby granted, free of charge, to any person obtaining a copy 
      of this software and associated documentation files(the "Software"), to deal 
      in the Software without restriction, including without limitation the rights 
      to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
      copies of the Software, and to permit persons to whom the Software is 
      furnished to do so, subject to the following conditions: 

      The above copyright notice and this permission notice shall be included in 
      all copies or substantial portions of the Software. 

      THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
      IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
      FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE 
      AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
      LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
      OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 
      THE SOFTWARE. 
      */ 

      var mem = new System.IO.MemoryStream(publicKey); 
      BinaryReader binr = new BinaryReader(mem); //wrap Memory Stream with BinaryReader for easy reading 
      byte bt = 0; 
      ushort twobytes = 0; 

      twobytes = binr.ReadUInt16(); 
      if (twobytes == 0x8130) //data read as little endian order (actual data order for Sequence is 30 81) 
       binr.ReadByte(); //advance 1 byte 
      else if (twobytes == 0x8230) 
       binr.ReadInt16(); //advance 2 bytes 
      else 
       return null; 

      var seq = binr.ReadBytes(15); //read the Sequence OID 
      if (!CompareBytearrays(seq, SeqOID)) //make sure Sequence for OID is correct 
       return null; 

      twobytes = binr.ReadUInt16(); 
      if (twobytes == 0x8103) //data read as little endian order (actual data order for Bit String is 03 81) 
       binr.ReadByte(); //advance 1 byte 
      else if (twobytes == 0x8203) 
       binr.ReadInt16(); //advance 2 bytes 
      else 
       return null; 

      bt = binr.ReadByte(); 
      if (bt != 0x00) //expect null byte next 
       return null; 

      twobytes = binr.ReadUInt16(); 
      if (twobytes == 0x8130) //data read as little endian order (actual data order for Sequence is 30 81) 
       binr.ReadByte(); //advance 1 byte 
      else if (twobytes == 0x8230) 
       binr.ReadInt16(); //advance 2 bytes 
      else 
       return null; 

      twobytes = binr.ReadUInt16(); 
      byte lowbyte = 0x00; 
      byte highbyte = 0x00; 

      if (twobytes == 0x8102) //data read as little endian order (actual data order for Integer is 02 81) 
       lowbyte = binr.ReadByte(); // read next bytes which is bytes in modulus 
      else if (twobytes == 0x8202) 
      { 
       highbyte = binr.ReadByte(); //advance 2 bytes 
       lowbyte = binr.ReadByte(); 
      } 
      else 
       return null; 
      byte[] modint = { lowbyte, highbyte, 0x00, 0x00 }; //reverse byte order since asn.1 key uses big endian order 
      int modsize = BitConverter.ToInt32(modint, 0); 

      int firstbyte = binr.PeekChar(); 
      if (firstbyte == 0x00) 
      { //if first byte (highest order) of modulus is zero, don't include it 
       binr.ReadByte(); //skip this null byte 
       modsize -= 1; //reduce modulus buffer size by 1 
      } 

      byte[] modulus = binr.ReadBytes(modsize); //read the modulus bytes 

      if (binr.ReadByte() != 0x02)  //expect an Integer for the exponent data 
       return null; 
      int expbytes = (int)binr.ReadByte(); // should only need one byte for actual exponent data (for all useful values) 
      byte[] exponent = binr.ReadBytes(expbytes); 

      // ------- create RSACryptoServiceProvider instance and initialize with public key ----- 
      RSACryptoServiceProvider RSA = new RSACryptoServiceProvider(); 
      RSAParameters RSAKeyInfo = new RSAParameters(); 
      RSAKeyInfo.Modulus = modulus; 
      RSAKeyInfo.Exponent = exponent; 
      RSA.ImportParameters(RSAKeyInfo); 
      RSA.PersistKeyInCsp = false; 
      return RSA; 
     } 

     private static bool CompareBytearrays(byte[] a, byte[] b) 
     { 
      if (a.Length != b.Length) 
       return false; 
      int i = 0; 
      foreach (byte c in a) 
      { 
       if (c != b[i]) 
        return false; 
       i++; 
      } 
      return true; 
     } 

    } 
} 

Answer 1

RSACryptoServiceProvider es tun kann, vorausgesetzt, dass Sie den Schlüssel in PROV_RSA_AES (24), statt PROV_RSA_FULL (1) gespeichert haben.

new RSACryptoServiceProvider() sollte bereits eine PROV_RSA_AES werden machen, so dass der einzige Weg, den ich erwarten würde es für den Import eines Schlüssels falsch sein, wenn Sie auch einen CspParameters Eingang angegeben (und verändert sich ausdrücklich dwProvType Wert).

Wenn Sie ein vorhandenes RSACryptoServiceProvider Objekt haben, können Sie ein neues öffnen mit

CspParameters keyParams = new CspParameters(); 
CspKeyContainerInfo keyInfo = currentKey.CspKeyContainerInfo; 
keyParams.KeyContainerName = keyInfo.KeyContainerName; 
keyParams.ProviderType = 24 /*PROV_RSA_AES*/; 
keyParams.KeyNumber = (int)keyInfo.KeyNumber; 
keyParams.Flags = CspProviderFlags.UseExistingKey; 

if (keyInfo.MachineKeyStore) 
    keyParams.Flags |= CspProviderFlags.UseMachineKeyStore; 

return new RSACryptoServiceProvider(keyParams); 

Oder, wenn Sie auf .NET 4.6+ sind, wechseln Sie zu RSACng, die für SHA- viel stabiler Träger 2 Unterschriften

Answer 2

Nach der Besprechung mit der dritten Partei, die die Informationen zur Verfügung stellt, erscheint mir der falsche öffentliche Schlüssel. Nach dem Umschalten auf den richtigen öffentlichen Schlüssel ist die Überprüfung nun erfolgreich.