C# PDF加密

引用 Nuget itext7

using iText.Kernel.Pdf;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime;
using System.Text;
using System.Threading.Tasks;

namespace Common
{
    public class PDFHepler
    {
        public enum EncryptionType
        {
            AES_256 = EncryptionConstants.ENCRYPTION_AES_256,
            AES_128 = EncryptionConstants.ENCRYPTION_AES_128,
            RC4_128 = EncryptionConstants.STANDARD_ENCRYPTION_128,
            RC4_40 = EncryptionConstants.STANDARD_ENCRYPTION_40
        }
        /// <summary>
        /// PDF加密
        /// </summary>
        /// <param name="inputPath">载入完整路径</param>
        /// <param name="outputPath">保存完整路径</param>
        /// <param name="password">密码</param>
        public static void PDFEncrypt(string inputPath, string outputPath, string password)
        {
            // Set document options
            int document_options = 0;
            PdfReader reader = new PdfReader(inputPath);    // Create a PdfReader with the input file.
            WriterProperties prop = new WriterProperties(); // Set properties of output
            prop.SetStandardEncryption(Encoding.ASCII.GetBytes(password), null, document_options, (int)EncryptionType.AES_256);  // Enable encryption

            PdfWriter writer = new PdfWriter(outputPath, prop); // Set up the output file
            using (PdfDocument pdf = new PdfDocument(reader, writer))// Create the new document
            {

            } 
            //PdfDocument pdf = new PdfDocument(reader, writer);  // Create the new document
            //pdf.Close();	// Close the output document.
        }
    }
}