软件注册码随笔

用到的是：BouncyCastle.Crypto.dll类库

官网：http://www.bouncycastle.org/csharp/

生成密钥对

 RsaKeyPairGenerator keyGenerator = new RsaKeyPairGenerator();
            //密钥构造器
            RsaKeyGenerationParameters p = new RsaKeyGenerationParameters(BigInteger.ValueOf(3), new SecureRandom(), 1024, 25);
            //初始化密钥构造器
            keyGenerator.Init(p);
            //密钥对
            AsymmetricCipherKeyPair keyPair = keyGenerator.GenerateKeyPair();
            //公钥和私钥
            AsymmetricKeyParameter publicKey = keyPair.Public;
            AsymmetricKeyParameter privateKey = keyPair.Private;

保存密钥对到文件（我这里用*.key形式保存的，当然也可以用其它的）

 private static void SavePublicKey(AsymmetricKeyParameter publicKey)
        {
            SubjectPublicKeyInfo publicKeyInfo = SubjectPublicKeyInfoFactory.CreateSubjectPublicKeyInfo(publicKey);
            Asn1Object ao = publicKeyInfo.ToAsn1Object();
            byte[] publicKeyByte = ao.GetEncoded();
            FileStream fs = new FileStream(@"D:\public.key", FileMode.Create, FileAccess.Write);
            fs.Write(publicKeyByte, 0, publicKeyByte.Length);
            fs.Close();
        }

 private static void SavePrivateKey(AsymmetricKeyParameter privateKey)
        {
            PrivateKeyInfo privateKeyInfo = PrivateKeyInfoFactory.CreatePrivateKeyInfo(privateKey);
            Asn1Object ao = privateKeyInfo.ToAsn1Object();
            byte[] privateKeyByte = ao.GetEncoded();
            FileStream fs = new FileStream(@"D:\private.key", FileMode.Create, FileAccess.Write);
            fs.Write(privateKeyByte, 0, privateKeyByte.Length);
            fs.Close();
        }

软件注册基本结构：

自己拥有私密：privatekey

客户拥有公密：publicKey

1：客户端生成序列号

2：客户把序列号告诉私密拥有者

3：私密拥有者用私钥加密信息（时间，版本，或者什么的）

4：加密后的信息给客户，客户在软件操作，验证

1，2步骤不用说了，很简单

直接3，4步骤

私密加密

IAsymmetricBlockCipher enginePrivate = new RsaEngine();
            Asn1Object aobj = Asn1Object.FromStream(new FileStream(@"D:\private.key", FileMode.Open, FileAccess.Read));
            PrivateKeyInfo priKey = PrivateKeyInfo.GetInstance(aobj);
            AsymmetricKeyParameter privateKey = PrivateKeyFactory.CreateKey(priKey);
            enginePrivate.Init(true, privateKey);
            byte[] enData = enginePrivate.ProcessBlock(data1, 0, data1.Length);
            string tempEnString = ConvertBytesToHexString(enData);

公密解密

 byte[] data = ConvertHexStringToBytes(tempEnString);
            IAsymmetricBlockCipher engine = new RsaEngine();
            Asn1Object aobject = Asn1Object.FromStream(new FileStream(@"D:\public.key", FileMode.Open, FileAccess.Read));  //a.puk??
            SubjectPublicKeyInfo pubInfo = SubjectPublicKeyInfo.GetInstance(aobject);
            AsymmetricKeyParameter publicKey = (RsaKeyParameters)PublicKeyFactory.CreateKey(pubInfo);
            engine.Init(false, publicKey);
            engine.GetInputBlockSize();
            byte[] deData = engine.ProcessBlock(data, 0, data.Length);
            string tempString = byteToHexStr(deData);

帮助类

 private string byteToHexStr(byte[] bytes)
        {
            string returnStr = "";

            if (bytes != null)
            {

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

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

                }
            }
            return returnStr;
        }
        public byte[] ConvertHexStringToBytes(string hexString)
        {
            int len = hexString.Length / 2;
            byte[] bytes = new byte[len];
            for (int i = 0; i < len; i++)
            {
                bytes[i] = Convert.ToByte(hexString.Substring(i * 2, 2), 16);
            }
            return bytes;
        }
        public string ConvertBytesToHexString(byte[] bytes)
        {
            StringBuilder sb = new StringBuilder();
            foreach (byte b in bytes)
            {
                sb.Append(string.Format("{0:X2}", b).PadLeft(2, '0'));
            }
            return sb.ToString();
        }

直接看代码，有些东西是自己要研究的，