C＃導出私鑰/ RSA公鑰到PEM串

我有System.Security.Cryptography.RSACryptoServiceProvider的實例，我需要出口這是關鍵，PEM的字符串 - 這樣的：C＃導出私鑰/ RSA公鑰到PEM串

但根據MSDN文檔沒有這樣的選項，只有某種類型的XML導出。我無法使用任何第三方庫，如BouncyCastle。有沒有什麼辦法可以產生這個字符串？

來源

2014-05-19 nidzo732

如何以及在哪裏做了那個類的實例有一個鍵？ – rene

這個痛點來源於.Net及其[RFC 3275]（https://www.ietf.org/rfc/rfc3275.txt）中XML編碼的使用。 .Net不使用ASN.1/DER或PEM編碼密鑰。我認爲它是唯一能以這種方式執行任務的加密庫。 – jww

請注意：下面的代碼是用於導出私鑰密鑰。如果您想要輸出公鑰密鑰，請參閱我給出的回答here。

該PEM格式僅僅是ASN.1 DER編碼的密鑰（每PKCS#1）轉換爲Base64。鑑於代表密鑰所需的字段數量有限，創建快速和簡潔的DER編碼器以輸出適當的格式，然後Base64對其進行編碼是相當直接的。因此，下面的代碼是不是特別優雅，但這項工作：

private static void ExportPrivateKey(RSACryptoServiceProvider csp, TextWriter outputStream) 
{ 
    if (csp.PublicOnly) throw new ArgumentException("CSP does not contain a private key", "csp"); 
    var parameters = csp.ExportParameters(true); 
    using (var stream = new MemoryStream()) 
    { 
     var writer = new BinaryWriter(stream); 
     writer.Write((byte)0x30); // SEQUENCE 
     using (var innerStream = new MemoryStream()) 
     { 
      var innerWriter = new BinaryWriter(innerStream); 
      EncodeIntegerBigEndian(innerWriter, new byte[] { 0x00 }); // Version 
      EncodeIntegerBigEndian(innerWriter, parameters.Modulus); 
      EncodeIntegerBigEndian(innerWriter, parameters.Exponent); 
      EncodeIntegerBigEndian(innerWriter, parameters.D); 
      EncodeIntegerBigEndian(innerWriter, parameters.P); 
      EncodeIntegerBigEndian(innerWriter, parameters.Q); 
      EncodeIntegerBigEndian(innerWriter, parameters.DP); 
      EncodeIntegerBigEndian(innerWriter, parameters.DQ); 
      EncodeIntegerBigEndian(innerWriter, parameters.InverseQ); 
      var length = (int)innerStream.Length; 
      EncodeLength(writer, length); 
      writer.Write(innerStream.GetBuffer(), 0, length); 
     } 

     var base64 = Convert.ToBase64String(stream.GetBuffer(), 0, (int)stream.Length).ToCharArray(); 
     outputStream.WriteLine("-----BEGIN RSA PRIVATE KEY-----"); 
     // Output as Base64 with lines chopped at 64 characters 
     for (var i = 0; i < base64.Length; i += 64) 
     { 
      outputStream.WriteLine(base64, i, Math.Min(64, base64.Length - i)); 
     } 
     outputStream.WriteLine("-----END RSA PRIVATE KEY-----"); 
    } 
} 

private static void EncodeLength(BinaryWriter stream, int length) 
{ 
    if (length < 0) throw new ArgumentOutOfRangeException("length", "Length must be non-negative"); 
    if (length < 0x80) 
    { 
     // Short form 
     stream.Write((byte)length); 
    } 
    else 
    { 
     // Long form 
     var temp = length; 
     var bytesRequired = 0; 
     while (temp > 0) 
     { 
      temp >>= 8; 
      bytesRequired++; 
     } 
     stream.Write((byte)(bytesRequired | 0x80)); 
     for (var i = bytesRequired - 1; i >= 0; i--) 
     { 
      stream.Write((byte)(length >> (8 * i) & 0xff)); 
     } 
    } 
} 

private static void EncodeIntegerBigEndian(BinaryWriter stream, byte[] value, bool forceUnsigned = true) 
{ 
    stream.Write((byte)0x02); // INTEGER 
    var prefixZeros = 0; 
    for (var i = 0; i < value.Length; i++) 
    { 
     if (value[i] != 0) break; 
     prefixZeros++; 
    } 
    if (value.Length - prefixZeros == 0) 
    { 
     EncodeLength(stream, 1); 
     stream.Write((byte)0); 
    } 
    else 
    { 
     if (forceUnsigned && value[prefixZeros] > 0x7f) 
     { 
      // Add a prefix zero to force unsigned if the MSB is 1 
      EncodeLength(stream, value.Length - prefixZeros + 1); 
      stream.Write((byte)0); 
     } 
     else 
     { 
      EncodeLength(stream, value.Length - prefixZeros); 
     } 
     for (var i = prefixZeros; i < value.Length; i++) 
     { 
      stream.Write(value[i]); 
     } 
    } 
}

來源

2014-05-19 14:06:36 Iridium

太好了，這個工作很完美，但我如何導出公鑰。它有相似的結構嗎？我已經試過用指數和模數（公鑰的內容）來做這件事，但它沒有返回有效的結果。如何獲取公鑰字符串？ – nidzo732

沒關係。我得到它的工作，我忘了刪除版本的一部分。現在它也輸出公鑰。 – nidzo732

對於那些感興趣的，正確的導出公鑰可以通過我的答案中的代碼來完成：http://stackoverflow.com/questions/28406888/c-sharp-rsa-public-key-output-not-correct/28407693 ＃28407693其中重新使用這個答案的一些方法。 – Iridium

對於出口PublicKey使用此代碼：

public static String ExportPublicKeyToPEMFormat(RSACryptoServiceProvider csp) 
{ 
    TextWriter outputStream = new StringWriter(); 

    var parameters = csp.ExportParameters(false); 
    using (var stream = new MemoryStream()) 
    { 
     var writer = new BinaryWriter(stream); 
     writer.Write((byte)0x30); // SEQUENCE 
     using (var innerStream = new MemoryStream()) 
     { 
      var innerWriter = new BinaryWriter(innerStream); 
      EncodeIntegerBigEndian(innerWriter, new byte[] { 0x00 }); // Version 
      EncodeIntegerBigEndian(innerWriter, parameters.Modulus); 
      EncodeIntegerBigEndian(innerWriter, parameters.Exponent); 

      //All Parameter Must Have Value so Set Other Parameter Value Whit Invalid Data (for keeping Key Structure use "parameters.Exponent" value for invalid data) 
      EncodeIntegerBigEndian(innerWriter, parameters.Exponent); // instead of parameters.D 
      EncodeIntegerBigEndian(innerWriter, parameters.Exponent); // instead of parameters.P 
      EncodeIntegerBigEndian(innerWriter, parameters.Exponent); // instead of parameters.Q 
      EncodeIntegerBigEndian(innerWriter, parameters.Exponent); // instead of parameters.DP 
      EncodeIntegerBigEndian(innerWriter, parameters.Exponent); // instead of parameters.DQ 
      EncodeIntegerBigEndian(innerWriter, parameters.Exponent); // instead of parameters.InverseQ 

      var length = (int)innerStream.Length; 
      EncodeLength(writer, length); 
      writer.Write(innerStream.GetBuffer(), 0, length); 
     } 

     var base64 = Convert.ToBase64String(stream.GetBuffer(), 0, (int)stream.Length).ToCharArray(); 
     outputStream.WriteLine("-----BEGIN PUBLIC KEY-----"); 
     // Output as Base64 with lines chopped at 64 characters 
     for (var i = 0; i < base64.Length; i += 64) 
     { 
      outputStream.WriteLine(base64, i, Math.Min(64, base64.Length - i)); 
     } 
     outputStream.WriteLine("-----END PUBLIC KEY-----"); 

     return outputStream.ToString(); 

    } 
} 

private static void EncodeIntegerBigEndian(BinaryWriter stream, byte[] value, bool forceUnsigned = true) 
{ 
    stream.Write((byte)0x02); // INTEGER 
    var prefixZeros = 0; 
    for (var i = 0; i < value.Length; i++) 
    { 
     if (value[i] != 0) break; 
     prefixZeros++; 
    } 
    if (value.Length - prefixZeros == 0) 
    { 
     EncodeLength(stream, 1); 
     stream.Write((byte)0); 
    } 
    else 
    { 
     if (forceUnsigned && value[prefixZeros] > 0x7f) 
     { 
      // Add a prefix zero to force unsigned if the MSB is 1 
      EncodeLength(stream, value.Length - prefixZeros + 1); 
      stream.Write((byte)0); 
     } 
     else 
     { 
      EncodeLength(stream, value.Length - prefixZeros); 
     } 
     for (var i = prefixZeros; i < value.Length; i++) 
     { 
      stream.Write(value[i]); 
     } 
    } 
} 

private static void EncodeLength(BinaryWriter stream, int length) 
{ 
    if (length < 0) throw new ArgumentOutOfRangeException("length", "Length must be non-negative"); 
    if (length < 0x80) 
    { 
     // Short form 
     stream.Write((byte)length); 
    } 
    else 
    { 
     // Long form 
     var temp = length; 
     var bytesRequired = 0; 
     while (temp > 0) 
     { 
      temp >>= 8; 
      bytesRequired++; 
     } 
     stream.Write((byte)(bytesRequired | 0x80)); 
     for (var i = bytesRequired - 1; i >= 0; i--) 
     { 
      stream.Write((byte)(length >> (8 * i) & 0xff)); 
     } 
    } 
}

來源

2014-08-31 11:44:47 abasan

我不得不刪除'EncodeIntegerBigEndian（innerWriter，new byte [] {0x00}）; // Version'行，以便能夠在Poco庫的[Crypto :: RSAKey]（http://pocoproject.org/docs/Poco.Crypto.RSAKey.html）中加載生成的PEM文件。 – Isaac

這不適合我。相反，我使用@銥星的其他帖子http://stackoverflow.com/questions/28406888/c-sharp-rsa-public-key-output-not-correct/28407693#28407693根據他的回答下他的評論。 –

這六個額外的寫入是什麼......一個RSA公鑰是'{n，e}'對。您應該檢查PKCS＃1的正確格式，而不是像上面那樣分享黑客。 – jww

對於別人誰在原來的答案是顯而易見的複雜性猶豫不決（這是非常有幫助的，不要誤會我的意思），我想我會後我的解決方案這是一個小更直接IMO（但仍然在原有基礎上的答案）：

public class RsaCsp2DerConverter { 
    private const int MaximumLineLength = 64; 

    // Based roughly on: http://stackoverflow.com/a/23739932/1254575 

    public RsaCsp2DerConverter() { 

    } 

    public byte[] ExportPrivateKey(String cspBase64Blob) { 
     if (String.IsNullOrEmpty(cspBase64Blob) == true) 
     throw new ArgumentNullException(nameof(cspBase64Blob)); 

     var csp = new RSACryptoServiceProvider(); 

     csp.ImportCspBlob(Convert.FromBase64String(cspBase64Blob)); 

     if (csp.PublicOnly) 
     throw new ArgumentException("CSP does not contain a private key!", nameof(csp)); 

     var parameters = csp.ExportParameters(true); 

     var list = new List<byte[]> { 
     new byte[] {0x00}, 
     parameters.Modulus, 
     parameters.Exponent, 
     parameters.D, 
     parameters.P, 
     parameters.Q, 
     parameters.DP, 
     parameters.DQ, 
     parameters.InverseQ 
     }; 

     return SerializeList(list); 
    } 

    private byte[] Encode(byte[] inBytes, bool useTypeOctet = true) { 
     int length = inBytes.Length; 
     var bytes = new List<byte>(); 

     if (useTypeOctet == true) 
     bytes.Add(0x02); // INTEGER 

     bytes.Add(0x84); // Long format, 4 bytes 
     bytes.AddRange(BitConverter.GetBytes(length).Reverse()); 
     bytes.AddRange(inBytes); 

     return bytes.ToArray(); 
    } 

    public String PemEncode(byte[] bytes) { 
     if (bytes == null) 
     throw new ArgumentNullException(nameof(bytes)); 

     var base64 = Convert.ToBase64String(bytes); 

     StringBuilder b = new StringBuilder(); 
     b.Append("-----BEGIN RSA PRIVATE KEY-----\n"); 

     for (int i = 0; i < base64.Length; i += MaximumLineLength) 
     b.Append($"{ base64.Substring(i, Math.Min(MaximumLineLength, base64.Length - i)) }\n"); 

     b.Append("-----END RSA PRIVATE KEY-----\n"); 

     return b.ToString(); 
    } 

    private byte[] SerializeList(List<byte[]> list) { 
     if (list == null) 
     throw new ArgumentNullException(nameof(list)); 

     var keyBytes = list.Select(e => Encode(e)).SelectMany(e => e).ToArray(); 

     var binaryWriter = new BinaryWriter(new MemoryStream()); 
     binaryWriter.Write((byte) 0x30); // SEQUENCE 
     binaryWriter.Write(Encode(keyBytes, false)); 
     binaryWriter.Flush(); 

     var result = ((MemoryStream) binaryWriter.BaseStream).ToArray(); 

     binaryWriter.BaseStream.Dispose(); 
     binaryWriter.Dispose(); 

     return result; 
    } 
}

來源

2016-10-28 13:54:38 Steve

C＃導出私鑰/ RSA公鑰到PEM串

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