C# 对PDF文档加密、解密（基于Spire.Cloud.SDK for .NET）

using System;
using Spire.Cloud.Pdf.Sdk.Client;
using Spire.Cloud.Pdf.Sdk.Api;
using System.IO;
using System.Collections.Generic;

namespace Encryt
{
  class Program
  {  
    //配置账号信息
    static String appId = "App ID";
    static String appKey = "App Key";
    static String baseUrl = "https://api.e-iceblue.cn";
    static Configuration PdfConfiguration = new Configuration(appId, appKey, baseUrl);
    static PdfSecurityApi PdfSecurityApi = new PdfSecurityApi(PdfConfiguration);
    static void Main(string[] args)
    {
      string name = "sample.pdf";//源文档
      string destFilePath = "pdfsecurity/Encrypt.pdf";//结果文档路径（将结果文档存放在pdfsecurity文件夹下）
      string userPassword = "123";//设置用户密码   
      string ownerPassword = "321";//设置所有者密码
      string keySize = "Key40Bit";//设置keySize(如果不需要设置，可设置为null)
      List<string> permissionsFlags = new List<string>();//设置permissionsFlags(如果不需要设置，可设置为null)
      permissionsFlags.Add("Print");
      string folder = "input";//源文档所在文件夹
      string password = null;//源文档密码
      string storage = null;

      //调用方法加密文档
      PdfSecurityApi.EncryptDocumentInStorage(name,destFilePath,userPassword,ownerPassword,keySize,permissionsFlags,folder,storage,password);
    }    
  }
}

using System;
using Spire.Cloud.Pdf.Sdk.Client;
using Spire.Cloud.Pdf.Sdk.Api;

namespace Decrypt
{
  class Program
  {
    //配置账号信息
    static String appId = "App ID";
    static String appKey = "App Key";
    static String baseUrl = "https://api.e-iceblue.cn";
    static Configuration PdfConfiguration = new Configuration(appId, appKey, baseUrl);

    static PdfSecurityApi PdfSecurityApi = new PdfSecurityApi(PdfConfiguration);
    static void Main(string[] args)
    {
      string name = "Encrypt.pdf";//源文档
      string destFilePath = "pdfsecurity/Decrypt.pdf";//结果文档路径（pdfsecurity为结果文档所在文件夹）
      string password = "321";//文档密码（这里需要使用的是ownerpassword)
      string folder = "pdfsecurity";//源文档所在文件夹
      string storage = null;

      //调用方法解密文档
      PdfSecurityApi.DecryptDocumentInStorage(name,destFilePath,password,folder,storage);
    }   
  }
}