C# 使用Bouncy Castle将RSA公钥转换为RFC 4716公钥

我希望将RSA公钥转换为可以用作SSH公钥的内容

目前，Bouncy Castle为我生成了一个公钥，如下所示：

-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAq1Y5300i8bN+cI2U3wJE
Kh3xG/.........jbuz+WB0vvG
P25UwCle2k5siVMwbImEYsr+Xt0dsMmGVB3/6MHAqrM3QQdQ8p2E5TyzL+JYa1FT
gwIDAQAB
-----END PUBLIC KEY-----

var r = new Org.BouncyCastle.Crypto.Generators.RsaKeyPairGenerator();
r.Init(new KeyGenerationParameters(new SecureRandom(), 2048));
var keys = r.GenerateKeyPair();

var stringWriter = new StringWriter();

var pemWriter = new PemWriter(stringWriter);
pemWriter.WriteObject(keys.Private);
pemWriter.Writer.Flush();
stringWriter.Close();
PrivateKey = stringWriter.ToString();

stringWriter = new StringWriter();
pemWriter = new PemWriter(stringWriter);
pemWriter.WriteObject(keys.Public);
pemWriter.Writer.Flush();
stringWriter.Close();
PublicKey = stringWriter.ToString();

我希望它的RFC 4716格式与此类似：

ssh rsa AAAAB3NzaC1yc2..G1p2Ag3mZLFsks7RNHVLgMsGIAikQ=

到目前为止，我使用Bouncy Castle的代码如下所示：

-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAq1Y5300i8bN+cI2U3wJE
Kh3xG/.........jbuz+WB0vvG
P25UwCle2k5siVMwbImEYsr+Xt0dsMmGVB3/6MHAqrM3QQdQ8p2E5TyzL+JYa1FT
gwIDAQAB
-----END PUBLIC KEY-----

var r = new Org.BouncyCastle.Crypto.Generators.RsaKeyPairGenerator();
r.Init(new KeyGenerationParameters(new SecureRandom(), 2048));
var keys = r.GenerateKeyPair();

var stringWriter = new StringWriter();

var pemWriter = new PemWriter(stringWriter);
pemWriter.WriteObject(keys.Private);
pemWriter.Writer.Flush();
stringWriter.Close();
PrivateKey = stringWriter.ToString();

stringWriter = new StringWriter();
pemWriter = new PemWriter(stringWriter);
pemWriter.WriteObject(keys.Public);
pemWriter.Writer.Flush();
stringWriter.Close();
PublicKey = stringWriter.ToString();

如何重新格式化和编码密钥，使其看起来像这样

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有人用Bouncy Castle或类似的工具创建了SSH公钥吗？

意识到你的帖子已经发布了几个月了，但是如果你仍然在寻找，请尝试下面的代码片段，灵感来自gotoalberto on

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我在BouncyCastle中找不到用于此的现成函数。因此，解决方法是使用

PemReader

，然后格式化结果。结果将作为

publicsh

属性提供：

using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Generators;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Math;
using Org.BouncyCastle.OpenSsl;
using Org.BouncyCastle.Security;
using System;
using System.IO;
using System.Text;

namespace Deploy4Me.Common.Utils
{
    public class RSAKey
    {
        public string PublicPEM { get; set; }
        public string PrivatePEM { get; set; }
        public string PublicSSH { get; set; }
    }

    public static class RSA
    {
        public static RSAKey Generate()
        {
            try
            {
                RSAKey result = new RSAKey();
                IAsymmetricCipherKeyPairGenerator gen;
                KeyGenerationParameters param;
                gen = new RsaKeyPairGenerator();
                param = new RsaKeyGenerationParameters(
                    BigInteger.ValueOf(3L),
                    new SecureRandom(),
                    2048,
                    80
                );
                gen.Init(param);
                AsymmetricCipherKeyPair pair = gen.GenerateKeyPair(); 
                using(TextWriter textWriter = new StringWriter())
                {
                    PemWriter wr = new PemWriter(textWriter);
                    wr.WriteObject(pair.Private);
                    wr.Writer.Flush();

                    result.PrivatePEM = textWriter.ToString();
                }

                using (TextWriter textWriter = new StringWriter())
                {
                    PemWriter wr = new PemWriter(textWriter);
                    wr.WriteObject(pair.Public);
                    wr.Writer.Flush();

                    result.PublicPEM = textWriter.ToString();
                }

                using (StringReader sr = new StringReader(result.PublicPEM))
                {
                    PemReader reader = new PemReader(sr);
                    RsaKeyParameters r = (RsaKeyParameters)reader.ReadObject();
                    byte[] sshrsa_bytes = Encoding.Default.GetBytes("ssh-rsa");
                    byte[] n = r.Modulus.ToByteArray();
                    byte[] e = r.Exponent.ToByteArray();

                    string buffer64;
                    using(MemoryStream ms = new MemoryStream()){
                        ms.Write(ToBytes(sshrsa_bytes.Length), 0, 4);
                        ms.Write(sshrsa_bytes, 0, sshrsa_bytes.Length);
                        ms.Write(ToBytes(e.Length), 0, 4);
                        ms.Write(e, 0, e.Length);
                        ms.Write(ToBytes(n.Length), 0, 4);
                        ms.Write(n, 0, n.Length);
                        ms.Flush();
                        buffer64 = Convert.ToBase64String(ms.ToArray());
                    }

                    result.PublicSSH = string.Format("ssh-rsa {0} generated-key", buffer64);
                }

                return result;
            }
            catch (Org.BouncyCastle.Crypto.CryptoException ex)
            {
                throw ex;
            }
        }

        private static byte[] ToBytes(int i)
        {
            byte[] bts = BitConverter.GetBytes(i);
            if (BitConverter.IsLittleEndian)
            {
                Array.Reverse(bts);
            }
            return bts;
        }
    }
}

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注意：我在微软工作，但这不是微软的答案，只是个人问题

添加到Pavels答案中

我发现出于某种原因，在生成3072位RSA密钥时，PuttyGen会生成与我不同的RSA公钥

经过研究，我发现在Putty Gen程序的源代码中，它似乎可以做到。字节数组的长度+1，加上一个前导0

对于BouncyCastle，您可以更改此行

                    ms.Write(ToBytes(n.Length), 0, 4);
                    ms.Write(n, 0, n.Length);

到

对于Microsoft.netRSACryptServiceProvider来说，它看起来是这样的

            RSACryptoServiceProvider RSA = new RSACryptoServiceProvider(3072);
            byte[] sshrsa_bytes = Encoding.Default.GetBytes("ssh-rsa");
            byte[] n = RSA.ExportParameters(false).Modulus;
            byte[] e = RSA.ExportParameters(false).Exponent;
            string buffer64;
            using (MemoryStream ms = new MemoryStream())
            {
                ms.Write(ToBytes(sshrsa_bytes.Length), 0, 4);
                ms.Write(sshrsa_bytes, 0, sshrsa_bytes.Length);
                ms.Write(ToBytes(e.Length), 0, 4);
                ms.Write(e, 0, e.Length);
                ms.Write(ToBytes(n.Length+1), 0, 4); //Remove the +1 if not Emulating Putty Gen
                ms.Write(new byte[] { 0 }, 0, 1); //Add a 0 to Emulate PuttyGen
                ms.Write(n, 0, n.Length);
                ms.Flush();
                buffer64 = Convert.ToBase64String(ms.ToArray());
            }

            string pubssh = string.Format("ssh-rsa {0} generated-key", buffer64);

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你可以看到我用于测试的私钥&putty gen源代码链接

这在.net中根本不起作用，似乎只是使用了完全不同的对象名。它在.net中可能不起作用，因为它是Java。同意Doug的说法-非常好，允许我生成用于SFTP的密钥。