Swift 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. Swift

func chilkatTest() {
    var success: Bool = 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

    let pdf = CkoPdf()!
    success = pdf.loadFile(filePath: "qa_data/pdf/two_page_memo.pdf")
    if success == false {
        print("\(pdf.lastErrorText!)")
        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.userPassword = "user-secret"
    pdf.ownerPassword = "owner-secret"

    //  An empty JSON asks for the defaults: AES-256, everything encrypted, every permission granted.
    let json = CkoJsonObject()!
    let jsonOut = CkoJsonObject()!
    success = pdf.protection(op: "encrypt", jsonIn: json, jsonOut: jsonOut)
    if success == false {
        print("\(pdf.lastErrorText!)")
        return
    }

    //  Nothing has been encrypted yet.  "pending" describes the security the PDF will be saved with.
    print("algorithm: \(jsonOut.string(of: "pending.algorithm")!)")
    print("PDF version: \(jsonOut.string(of: "pending.pdfVersion")!)")
    print("password needed to open: \(jsonOut.bool(of: "pending.userPasswordRequired"))")

    //  Writing the file applies it.
    success = pdf.writeFile(path: "qa_output/memo_encrypted.pdf")
    if success == false {
        print("\(pdf.lastErrorText!)")
        return
    }

    //  PreLoadCheck reports a file's encryption without loading it, and needs no password.
    let checker = CkoPdf()!
    let info = CkoJsonObject()!
    success = checker.preLoadCheck(path: "qa_output/memo_encrypted.pdf", jsonOut: info)
    if success == false {
        print("\(checker.lastErrorText!)")
        return
    }

    print("encrypted: \(info.bool(of: "encrypted"))")
    print("openPasswordRequired: \(info.bool(of: "openPasswordRequired"))")

    //  With the password, the PDF opens normally.
    let reader = CkoPdf()!
    reader.userPassword = "user-secret"
    success = reader.loadFile(filePath: "qa_output/memo_encrypted.pdf")
    if success == false {
        print("\(reader.lastErrorText!)")
        return
    }

    print("pages: \(reader.numPages.intValue)")

    //  Sample output:

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

}