如何將由openSSL生成的RSA公鑰加載到RSACryptoServiceProvider中？

Question

我寫一個.NET類讀取從我們的中央認證服務器的cookie。它包含UserId，一些時間戳和由openssl_sign（）使用2048位RSA密鑰和SHA1哈希創建的簽名。

當前的公鑰OpenSSL中的PEM格式提供的服務器和偶爾的變化上。我無法讀取使用的.Net獨（還）託管代碼，並制定了以下程序得到它的工作重點：從公鑰

檢查關鍵

• 提取指數和模量仍然是2048位
• 存儲密鑰長度，指數在資源的彈性模量，編譯和部署（從模量下降，導致零，使其工作）

的類，然後創建一個new RSACryptoServiceProvider(2048)並使用RSAParameters結構到CSP飼料公共組件。驗證簽名然後成功。

我希望得到這個工作沒有我創建，編譯和每次部署新議會的主要變化。爲了使事情變得有趣，我只想堅持託管代碼（排除我發現的大多數例子）。創造AsnEncodedData(oid, data)實例，但我發現，可以匹配的唯一OID，RSA又名1.2.840.113549.1.1.1時，沒有工作，只生產原始字節的東西，聽起來很完美，是內部ASN.1讀者。

補充：前公鑰

----- BEGIN PUBLIC KEY -----
MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBAMW90O6C17fapbS35auKolsy7kI0FOE1
C08y5HqgZ0rMXoocV4nHSHYBm2HVx2QSR5OLQtERgWDmxOu + vwU1GXUCAwEAAQ ==
----- END PUBLIC KEY-- ---

我發現pempublic.cs似乎解決這個使用（因爲它似乎）來自openSSL的源代碼。我將留下這個問題，看看是否有其他解決方案。

Answer 1

你的私鑰，所以它可能更容易產生從密鑰自簽名證書。您可以使用System.Security.Cryptography.X509Certificates.X509Certificate（我想你應該有DER/ASN.1格式，而吳丹PEM證書）來加載證書和X509Certificate.GetPublicKey()獲得公共密鑰。

Answer 2

要加載私鑰讓我們用這個代碼：

private RSACryptoServiceProvider GetPrivateKey(string privateKey) 
    { 
     byte[] privkey = Convert.FromBase64String(privateKey); 
     byte[] MODULUS, E, D, P, Q, DP, DQ, IQ; 

     // --------- Set up stream to decode the asn.1 encoded RSA private key ------ 
     MemoryStream mem = new MemoryStream(privkey); 
     BinaryReader binr = new BinaryReader(mem); //wrap Memory Stream with BinaryReader for easy reading 
     byte bt = 0; 
     ushort twobytes = 0; 
     int elems = 0; 
     try 
     { 
      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(); 
      if (twobytes != 0x0102) //version number 
       return null; 
      bt = binr.ReadByte(); 
      if (bt != 0x00) 
       return null; 


      //------ all private key components are Integer sequences ---- 
      elems = GetIntegerSize(binr); 
      MODULUS = binr.ReadBytes(elems); 

      elems = GetIntegerSize(binr); 
      E = binr.ReadBytes(elems); 

      elems = GetIntegerSize(binr); 
      D = binr.ReadBytes(elems); 

      elems = GetIntegerSize(binr); 
      P = binr.ReadBytes(elems); 

      elems = GetIntegerSize(binr); 
      Q = binr.ReadBytes(elems); 

      elems = GetIntegerSize(binr); 
      DP = binr.ReadBytes(elems); 

      elems = GetIntegerSize(binr); 
      DQ = binr.ReadBytes(elems); 

      elems = GetIntegerSize(binr); 
      IQ = binr.ReadBytes(elems); 

      // ------- create RSACryptoServiceProvider instance and initialize with public key ----- 
      CspParameters CspParameters = new CspParameters(); 
      CspParameters.Flags = CspProviderFlags.UseMachineKeyStore; 
      RSACryptoServiceProvider RSA = new RSACryptoServiceProvider(1024, CspParameters); 
      RSAParameters RSAparams = new RSAParameters(); 
      RSAparams.Modulus = MODULUS; 
      RSAparams.Exponent = E; 
      RSAparams.D = D; 
      RSAparams.P = P; 
      RSAparams.Q = Q; 
      RSAparams.DP = DP; 
      RSAparams.DQ = DQ; 
      RSAparams.InverseQ = IQ; 
      RSA.ImportParameters(RSAparams); 
      return RSA; 
     } 
     catch (Exception ex) 
     { 
      return null; 
     } 
     finally 
     { 
      binr.Close(); 
     } 
    } 

要加載公鑰讓我們用這個代碼：

private RSACryptoServiceProvider GetPublicKey(string publicKeyString) 
    { 
     // encoded OID sequence for PKCS #1 rsaEncryption szOID_RSA_RSA = "1.2.840.113549.1.1.1" 
     byte[] SeqOID = {0x30, 0x0D, 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01, 0x05, 0x00} ; 
     byte[] x509key; 
     byte[] seq = new byte[15]; 
     int x509size; 

     x509key = Convert.FromBase64String(publicKeyString); 
     x509size = x509key.Length; 

     // --------- Set up stream to read the asn.1 encoded SubjectPublicKeyInfo blob ------ 
     MemoryStream mem = new MemoryStream(x509key); 
     BinaryReader binr = new BinaryReader(mem); //wrap Memory Stream with BinaryReader for easy reading 
     byte bt = 0; 
     ushort twobytes = 0; 

     try 
     { 

      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; 

      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); 

      return RSA; 
     } 

     finally 
     { 
      binr.Close(); 
     } 
    } 

可以讀取original post here獲得更詳細