Swift Requires Chilkat v11.7.0+

Choose the PDF Encryption Algorithm: AES-256, AES-128 or RC4

See more PDF Protection Examples

Demonstrates the algorithmChoice option of the encrypt operation. aes-256 is the default and the one to use unless an older reader must open the file. aes-128 is for readers that predate AES-256. rc4-128 and rc4-40 are broken ciphers kept only for very old readers. Each algorithm needs a minimum PDF version, and the file header is raised to it when the PDF is saved, never lowered. A PDF saved with RC4 is written with a classic cross-reference table so that those old readers can parse it. 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 json = CkoJsonObject()!
    let jsonOut = CkoJsonObject()!
    let info = CkoJsonObject()!

    //  AES-256, the default.  Saved as PDF 1.7 with Adobe extension level 8.
    let pdf1 = CkoPdf()!
    success = pdf1.loadFile(filePath: "qa_data/pdf/two_page_memo.pdf")
    if success == false {
        print("\(pdf1.lastErrorText!)")
        return
    }

    pdf1.userPassword = "user-secret"
    pdf1.ownerPassword = "owner-secret"
    json.updateString(jsonPath: "algorithmChoice", value: "aes-256")
    success = pdf1.protection(op: "encrypt", jsonIn: json, jsonOut: jsonOut)
    if success == false {
        print("\(pdf1.lastErrorText!)")
        return
    }

    print("aes-256 will be saved as PDF \(jsonOut.string(of: "pending.pdfVersion")!), Adobe extension level \(jsonOut.int(of: "pending.adobeExtensionLevel").intValue)")
    success = pdf1.writeFile(path: "qa_output/memo_aes256.pdf")
    if success == false {
        print("\(pdf1.lastErrorText!)")
        return
    }

    success = pdf1.preLoadCheck(path: "qa_output/memo_aes256.pdf", jsonOut: info)
    if success == false {
        print("\(pdf1.lastErrorText!)")
        return
    }

    print("  saved file: \(info.string(of: "algorithm")!), PDF \(info.string(of: "pdfVersion")!)")

    //  AES-128, for readers that predate AES-256.  Saved as PDF 1.6.
    let pdf2 = CkoPdf()!
    success = pdf2.loadFile(filePath: "qa_data/pdf/two_page_memo.pdf")
    if success == false {
        print("\(pdf2.lastErrorText!)")
        return
    }

    pdf2.userPassword = "user-secret"
    pdf2.ownerPassword = "owner-secret"
    json.updateString(jsonPath: "algorithmChoice", value: "aes-128")
    success = pdf2.protection(op: "encrypt", jsonIn: json, jsonOut: jsonOut)
    if success == false {
        print("\(pdf2.lastErrorText!)")
        return
    }

    print("aes-128 will be saved as PDF \(jsonOut.string(of: "pending.pdfVersion")!)")
    success = pdf2.writeFile(path: "qa_output/memo_aes128.pdf")
    if success == false {
        print("\(pdf2.lastErrorText!)")
        return
    }

    success = pdf2.preLoadCheck(path: "qa_output/memo_aes128.pdf", jsonOut: info)
    if success == false {
        print("\(pdf2.lastErrorText!)")
        return
    }

    print("  saved file: \(info.string(of: "algorithm")!), PDF \(info.string(of: "pdfVersion")!)")

    //  RC4-128, a broken cipher, only for readers too old for AES.  Saved as PDF 1.4.
    let pdf3 = CkoPdf()!
    success = pdf3.loadFile(filePath: "qa_data/pdf/two_page_memo.pdf")
    if success == false {
        print("\(pdf3.lastErrorText!)")
        return
    }

    pdf3.userPassword = "user-secret"
    pdf3.ownerPassword = "owner-secret"
    json.updateString(jsonPath: "algorithmChoice", value: "rc4-128")
    success = pdf3.protection(op: "encrypt", jsonIn: json, jsonOut: jsonOut)
    if success == false {
        print("\(pdf3.lastErrorText!)")
        return
    }

    print("rc4-128 will be saved as PDF \(jsonOut.string(of: "pending.pdfVersion")!)")
    success = pdf3.writeFile(path: "qa_output/memo_rc4_128.pdf")
    if success == false {
        print("\(pdf3.lastErrorText!)")
        return
    }

    success = pdf3.preLoadCheck(path: "qa_output/memo_rc4_128.pdf", jsonOut: info)
    if success == false {
        print("\(pdf3.lastErrorText!)")
        return
    }

    print("  saved file: \(info.string(of: "algorithm")!), PDF \(info.string(of: "pdfVersion")!)")

    //  Sample output:

    //  aes-256 will be saved as PDF 1.7, Adobe extension level 8
    //    saved file: aes-256, PDF 1.7
    //  aes-128 will be saved as PDF 1.6
    //    saved file: aes-128, PDF 1.6
    //  rc4-128 will be saved as PDF 1.4
    //    saved file: rc4-128, PDF 1.4

}