.NET Core RSA 签名和验签（密钥为 16 进制编码）

使用 OpenSSL 生成公私钥对，命令：

$ openssl genrsa -out rsa_1024_priv.pem

$ openssl pkcs8 -topk8 -inform PEM -in rsa_1024_priv.pem -outform PEM -nocrypt -out rsa_1024_priv_pkcs8.pem

$ openssl rsa -in rsa_1024_priv_pkcs8.pem -pubout -out rsa_1024_pub.peml

rsa_1024_priv_pkcs8.pem和rsa_1024_pub.peml分别为公私钥对，复制出来里面的内容。

安装程序包：

install-package BouncyCastle.NetCore

创建帮助类：

public static class RSAHelper

{

    /// <summary>

    /// RSA签名

    /// </summary>

    /// <param name="content">数据</param>

    /// <param name="privateKey">RSA密钥</param>

    /// <returns></returns>

    public static string RsaSign(string content, string privateKey)

    {

        var signer = SignerUtilities.GetSigner("SHA1withRSA");

        //将java格式的rsa密钥转换成.net格式

        var privateKeyParam = (RsaPrivateCrtKeyParameters)PrivateKeyFactory.CreateKey(StrToToHexByte(privateKey));

        signer.Init(true, privateKeyParam);

        var plainBytes = Encoding.UTF8.GetBytes(content);

        signer.BlockUpdate(plainBytes, 0, plainBytes.Length);

        var signBytes = signer.GenerateSignature();

        return ByteToHexStr(signBytes);

    }

    /// <summary>

    /// RSA验签

    /// </summary>

    /// <param name="content">内容</param>

    /// <param name="publicKey">RSA公钥</param>

    /// <param name="signData">签名字段</param>

    /// <returns></returns>

    public static bool VerifySign(string content, string publicKey, string signData)

    {

        try

        {

            var signer = SignerUtilities.GetSigner("SHA1withRSA");

            var publicKeyParam = (RsaKeyParameters)PublicKeyFactory.CreateKey(StrToToHexByte(publicKey));

            signer.Init(false, publicKeyParam);

            var signBytes = StrToToHexByte(signData);

            var plainBytes = Encoding.UTF8.GetBytes(content);

            signer.BlockUpdate(plainBytes, 0, plainBytes.Length);

            var ret = signer.VerifySignature(signBytes);

            return ret;

        }

        catch (Exception ex)

        {

            return false;

        }

    }

    /// <summary>

    /// 字符串转16进制字节数组

    /// </summary>

    /// <param name="hexString"></param>

    /// <returns></returns>

    private static byte[] StrToToHexByte(string hexString)

    {

        hexString = hexString.Replace(" ", "");

        if ((hexString.Length % 2) != 0)

            hexString += " ";

        byte[] returnBytes = new byte[hexString.Length / 2];

        for (int i = 0; i < returnBytes.Length; i++)

            returnBytes[i] = Convert.ToByte(hexString.Substring(i * 2, 2), 16);

        return returnBytes;

    }

    /// <summary>

    /// 字节数组转16进制字符串

    /// </summary>

    /// <param name="bytes"></param>

    /// <returns></returns>

    public static string ByteToHexStr(byte[] bytes)

    {

        string returnStr = "";

        if (bytes != null)

        {

            for (int i = 0; i < bytes.Length; i++)

            {

                returnStr += bytes[i].ToString("X2");

            }

        }

        return returnStr;

    }

}

示例代码：

var content = "123";

var privateKey = RSAHelper.ByteToHexStr(Convert.FromBase64String("MIIBVQIBADANBgkqhkiG9w0BAQEFAASCAT8wggE7AgEAAkEA051JxQSrpN2cgI/fbCFjsALy7G055ichin5FF9qZ6VcdOa4/+V80FMLhR6ifRD2Sb/4qR0pMLnfkJadKBFM/QwIDAQABAkBMV3MUk6HEoXpjWwQUQ1tuVTIEH0eDA1zzVKhieaeK6Q1q4CiqJJ3fMkSTxgQZc6Wy11USJa6cRkYul4hsssddccBAiEA9Iiu7kxwbUE3DNnPzYi7st++fyo2ch9Wh2jF9BQB0YMCIQDdiXK/Y7673ucqBZdVpECJgp3DKCKlJPtfpuRmbSIvQQIhAM0IBdSclu+kbKoDvu7QpMCYRbuOA1Sw3fZvbPr4A4ZNAiBxcakpCNLrMcH+as6MNIg34oMXJL5ZAw8WdEgRi2EuAQIhALx6SB/hoTg91dGPd/Ql6pvRQaEG+HWda2yrW8fd41ot"));

var publicKey = RSAHelper.ByteToHexStr(Convert.FromBase64String("MFwwDQYJKoZIhvcNAQEBBQADSwAweniiO2ndANOdScUEq6TdnICP32whY7AC8uxtOeYnIYp+RRfamelXHTmuP/lfNBTC4Ueon0Q9km/+KkdKTC535CWnSgRTP0MCAwEAAQ=="));

var signData = RSAHelper.RsaSign(content, privateKey);

var result= RSAHelper.VerifySign(content, publicKey, signData);

注：publicKey和privateKey为 16 进制编码的公私钥对。