Comments by gaurav_mittal (Top 1 by date)

I am using DotNetZip library for compressing the pdf and encrypting the zip file. You may try it with the following code:

using(var zip = new Ionic.Zip.ZipFile())
{
zip.CompressionLevel = Ionic.Zlib.CompressionLevel.BestCompression;
zip.Encryption = EncryptionAlgorithm.WinZipAes128;
zip.Password = passKeyZIP;
zip.AddFile(finalPDFFullPath, "");
zip.Save(zipFilePath);
}

DotNetZip Library can be found at

http://dotnetzip.codeplex.com/