C# 常见加密解密类

大部分的加密类的使用方式是差不多的，其中MD5和SHA类似，均为不可逆；RSA位可加可解；DES和AES类似，均需要加密向量；文中所有明文加密后都转为了净荷明文。没必要转Byte转16进制字符串（难为不懂的？）！！

加密方式	加密向量	是否可逆
MD5、SHA	不需要	不可逆
RSA	不需要	可逆
AES、DES	需要	可逆

不可逆的不代表真的不可逆！

MD5

MD5为不可逆的加密方式一般用作密码验证，当密码加密结果一致时则认为登陆成功；

public class MD5
{
public string MD5Encrypt(string normalTxt)
{
var bytes= Encoding.Default.GetBytes(normalTxt);//求Byte[]数组
var Md5 = new MD5CryptoServiceProvider().ComputeHash(bytes);//求哈希值
return Convert.ToBase64String(Md5);//将Byte[]数组转为净荷明文(其实就是字符串)
}
}

RSA

加密：

public string RSAEncrypt(string normaltxt)
{
var bytes = Encoding.Default.GetBytes(normaltxt);
var encryptBytes= new RSACryptoServiceProvider(new CspParameters()).Encrypt(bytes,false);
return Convert.ToBase64String(encryptBytes);
}

解密：

public string RSADecrypt(string securityTxt)
{
try//必须使用Try catch,不然输入的字符串不是净荷明文程序就Gameover了
{
var bytes= Convert.FromBase64String(securityTxt);
var DecryptBytes =new RSACryptoServiceProvider(new CspParameters()).Decrypt(bytes,false);
return Encoding.Default.GetString(DecryptBytes);
}
catch (Exception)
{
return string.Empty;
}
}

DES

public class DES
{
public DES(byte[] keyvi)//密钥向量,8位就好了例如new byte[]{0x01,0x02,0x03,0x04,0x05,0x05,0x07}
{
this.keyvi = keyvi;
}
private byte[] keyvi;
public string DesEncrypt(string normalTxt,string EncryptKey)
{
var bytes= Encoding.Default.GetBytes(normalTxt);
var key = Encoding.UTF8.GetBytes(EncryptKey.PadLeft(8, '0').Substring(0, 8));
using (MemoryStream ms=new MemoryStream())
{
var encry = new DESCryptoServiceProvider();
CryptoStream cs = new CryptoStream(ms,encry.CreateEncryptor(key, keyvi),CryptoStreamMode.Write);
cs.Write(bytes,0,bytes.Length);
cs.FlushFinalBlock();
return Convert.ToBase64String(ms.ToArray());
}
}
public string DesDecrypt(string securityTxt, string EncryptKey)//解密
{
try
{
var bytes= Convert.FromBase64String(securityTxt);
var key = Encoding.UTF8.GetBytes(EncryptKey.PadLeft(8, '0').Substring(0, 8));
using (MemoryStream ms = new MemoryStream())
{
var descrypt = new DESCryptoServiceProvider();
CryptoStream cs = new CryptoStream(ms, descrypt.CreateDecryptor (key, keyvi), CryptoStreamMode.Write);
cs.Write(bytes,0,bytes.Length);
cs.FlushFinalBlock();
return Encoding.UTF8.GetString(ms.ToArray());
}

}
catch (Exception)
{
return string.Empty;
}
}
}

SHA

public class SHA//SHA为不可逆加密方式
{
public string SHA1Encrypt(string normalTxt)
{
var bytes = Encoding.Default.GetBytes(normalTxt);
var SHA = new SHA1CryptoServiceProvider();
var encryptbytes = SHA.ComputeHash(bytes);
return Convert.ToBase64String(encryptbytes);
}
public string SHA256Encrypt(string normalTxt)
{
var bytes = Encoding.Default.GetBytes(normalTxt);
var SHA256 = new SHA256CryptoServiceProvider();
var encryptbytes = SHA256.ComputeHash(bytes);
return Convert.ToBase64String(encryptbytes);
}
public string SHA384Encrypt(string normalTxt)
{
var bytes = Encoding.Default.GetBytes(normalTxt);
var SHA384 = new SHA384CryptoServiceProvider();
var encryptbytes = SHA384.ComputeHash(bytes);
return Convert.ToBase64String(encryptbytes);
}
public string SHA512Encrypt(string normalTxt)
{
var bytes = Encoding.Default.GetBytes(normalTxt);
var SHA512 = new SHA512CryptoServiceProvider();
var encryptbytes = SHA512.ComputeHash(bytes);
return Convert.ToBase64String(encryptbytes);
}
}

AES

public class AES
{
public AES(byte[] iv)
{
this.iv = iv;
}
byte[] iv;
public string AESEncrypt(string normalTxt,string key)
{
var bytes = Encoding.Default.GetBytes(normalTxt);
SymmetricAlgorithm des =Rijndael.Create();
des.Key = Encoding.Default.GetBytes(key);
des.IV = iv;
using (MemoryStream ms=new MemoryStream())
{
CryptoStream cs = new CryptoStream(ms,des.CreateEncryptor(),CryptoStreamMode.Write);
cs.Write(bytes, 0, bytes.Length);
cs.FlushFinalBlock();
return Convert.ToBase64String(ms.ToArray());
}
}
public string AESDecrypt(string securityTxt, string key)
{
try
{
var bytes = Convert.FromBase64String(securityTxt);
SymmetricAlgorithm des = Rijndael.Create();
des.Key = Encoding.Default.GetBytes(key);
des.IV = iv;
using (MemoryStream ms = new MemoryStream())
{
CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
cs.Write(bytes, 0, bytes.Length);
cs.FlushFinalBlock();
return Convert.ToBase64String(ms.ToArray());
}
}
catch (Exception)
{
return string.Empty;
}

}
}