微信小微商户敏感信息加密

官网上的代码

/*****************c#代码*********************/ 
/// <summary>
/// 加密敏感信息，传入明文和从微信支付获取到的敏感信息加密公钥，事先使用OpenSSL转换cert.pem文件输出为der文件
/// </summary>
/// <param name="text"></param>
/// <param name="publicKeyBase64"></param>
/// <returns></returns>
public static string Encrypt(string text, byte[] publicKeyDER)
{
var x509 = new X509Certificate2(publicKeyDER);
RSACryptoServiceProvider rsa = (RSACryptoServiceProvider)x509.PublicKey.Key;

var buff = rsa.Encrypt(Encoding.UTF8.GetBytes(text), false);

return Convert.ToBase64String(buff);
}

需要用到OpenSSL,可能本人比较笨,使用OpenSSL老是报错,cmd各种找不到,直接不用这个方式,使用github上的方式

1. 通过获取证书接口获取证书相关值
2. ciphertext associated_data nonce_dc
key这个key是api秘钥,商户自己设置的;

 string ciphertext = "获取到的值";
      string associated_data = "certificate";
      string nonce_dc = "获取证书的随机数";
      string key = "商户api秘钥";

      byte[] nsec = Convert.FromBase64String(ciphertext);

      //crypto_aead_aes256gcm_decrypt


      byte[] text = SecretAeadAes.Decrypt(
                  nsec,
                  System.Text.Encoding.Default.GetBytes(nonce_dc),
                  System.Text.Encoding.Default.GetBytes(key),
                  System.Text.Encoding.UTF8.GetBytes(associated_data));
      System.IO.FileStream fs = new System.IO.FileStream(@"3914A32659462BB090D406D3230842EEF3ED8130.txt", System.IO.FileMode.OpenOrCreate,System.IO.FileAccess.Write);
      fs.Write(text,0,text.Length);
      var res= Encrypt("sss", text);
    
    
    
    
    //加密  
    public static string Encrypt(string text, byte[] publicKeyDER)
    {
      var x509 = new X509Certificate2(publicKeyDER);
      RSACryptoServiceProvider rsa = (RSACryptoServiceProvider)x509.PublicKey.Key;

      var buff = rsa.Encrypt(Encoding.UTF8.GetBytes(text), false);

      return Convert.ToBase64String(buff);
    }

SecretAeadAes是使用github上的libsodium-net项目编译的方法,其中ciphertext associated_data nonce_dc
key这几个值加密就是生成der文件流,可以将它保存为文件,下次直接读取文件,不用每次都去生成