Go Requires Chilkat v11.7.0+

Password-Protect a PDF with AES-256 Encryption

See more PDF Protection Examples

Demonstrates the simplest way to encrypt a PDF so that it needs a password to open. The passwords come from the UserPassword and OwnerPassword properties, and Protection with the encrypt operation and an empty JSON uses the defaults: AES-256, everything encrypted, every permission granted. Protection only records the security the PDF will be saved with. Nothing is encrypted until WriteFile is called. Go

    success := false

    //  This example requires the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    //  The PDF used in this example is available at two_page_memo.pdf

    pdf := chilkat.NewPdf()
    success = pdf.LoadFile("qa_data/pdf/two_page_memo.pdf")
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        return
    }

    //  The passwords are taken from these two properties at the time Protection is called.
    //  The user password opens the PDF.  The owner password opens it too, and is the one needed
    //  later to change or remove the protection.
    pdf.SetUserPassword("user-secret")
    pdf.SetOwnerPassword("owner-secret")

    //  An empty JSON asks for the defaults: AES-256, everything encrypted, every permission granted.
    json := chilkat.NewJsonObject()
    jsonOut := chilkat.NewJsonObject()
    success = pdf.Protection("encrypt",json,jsonOut)
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        return
    }

    //  Nothing has been encrypted yet.  "pending" describes the security the PDF will be saved with.
    fmt.Println("algorithm: ", *jsonOut.StringOf("pending.algorithm"))
    fmt.Println("PDF version: ", *jsonOut.StringOf("pending.pdfVersion"))
    fmt.Println("password needed to open: ", *jsonOut.BoolOf("pending.userPasswordRequired"))

    //  Writing the file applies it.
    success = pdf.WriteFile("qa_output/memo_encrypted.pdf")
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        return
    }

    //  PreLoadCheck reports a file's encryption without loading it, and needs no password.
    checker := chilkat.NewPdf()
    info := chilkat.NewJsonObject()
    success = checker.PreLoadCheck("qa_output/memo_encrypted.pdf",info)
    if success == false {
        fmt.Println(checker.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        checker.DisposePdf()
        info.DisposeJsonObject()
        return
    }

    fmt.Println("encrypted: ", *info.BoolOf("encrypted"))
    fmt.Println("openPasswordRequired: ", *info.BoolOf("openPasswordRequired"))

    //  With the password, the PDF opens normally.
    reader := chilkat.NewPdf()
    reader.SetUserPassword("user-secret")
    success = reader.LoadFile("qa_output/memo_encrypted.pdf")
    if success == false {
        fmt.Println(reader.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        checker.DisposePdf()
        info.DisposeJsonObject()
        reader.DisposePdf()
        return
    }

    fmt.Println("pages: ", reader.NumPages())

    //  Sample output:

    //  algorithm: aes-256
    //  PDF version: 1.7
    //  password needed to open: True
    //  encrypted: True
    //  openPasswordRequired: True
    //  pages: 2

    pdf.DisposePdf()
    json.DisposeJsonObject()
    jsonOut.DisposeJsonObject()
    checker.DisposePdf()
    info.DisposeJsonObject()
    reader.DisposePdf()