Visual FoxPro 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. Visual FoxPro

LOCAL lnSuccess
LOCAL loJson
LOCAL loJsonOut
LOCAL loInfo
LOCAL loPdf1
LOCAL loPdf2
LOCAL loPdf3

lnSuccess = 0

*  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

loJson = CreateObject('Chilkat.JsonObject')
loJsonOut = CreateObject('Chilkat.JsonObject')
loInfo = CreateObject('Chilkat.JsonObject')

*  AES-256, the default.  Saved as PDF 1.7 with Adobe extension level 8.
loPdf1 = CreateObject('Chilkat.Pdf')
lnSuccess = loPdf1.LoadFile("qa_data/pdf/two_page_memo.pdf")
IF (lnSuccess = 0) THEN
    ? loPdf1.LastErrorText
    RELEASE loJson
    RELEASE loJsonOut
    RELEASE loInfo
    RELEASE loPdf1
    CANCEL
ENDIF

loPdf1.UserPassword = "user-secret"
loPdf1.OwnerPassword = "owner-secret"
loJson.UpdateString("algorithmChoice","aes-256")
lnSuccess = loPdf1.Protection("encrypt",loJson,loJsonOut)
IF (lnSuccess = 0) THEN
    ? loPdf1.LastErrorText
    RELEASE loJson
    RELEASE loJsonOut
    RELEASE loInfo
    RELEASE loPdf1
    CANCEL
ENDIF

? "aes-256 will be saved as PDF " + loJsonOut.StringOf("pending.pdfVersion") + ", Adobe extension level " + STR(loJsonOut.IntOf("pending.adobeExtensionLevel"))
lnSuccess = loPdf1.WriteFile("qa_output/memo_aes256.pdf")
IF (lnSuccess = 0) THEN
    ? loPdf1.LastErrorText
    RELEASE loJson
    RELEASE loJsonOut
    RELEASE loInfo
    RELEASE loPdf1
    CANCEL
ENDIF

lnSuccess = loPdf1.PreLoadCheck("qa_output/memo_aes256.pdf",loInfo)
IF (lnSuccess = 0) THEN
    ? loPdf1.LastErrorText
    RELEASE loJson
    RELEASE loJsonOut
    RELEASE loInfo
    RELEASE loPdf1
    CANCEL
ENDIF

? "  saved file: " + loInfo.StringOf("algorithm") + ", PDF " + loInfo.StringOf("pdfVersion")

*  AES-128, for readers that predate AES-256.  Saved as PDF 1.6.
loPdf2 = CreateObject('Chilkat.Pdf')
lnSuccess = loPdf2.LoadFile("qa_data/pdf/two_page_memo.pdf")
IF (lnSuccess = 0) THEN
    ? loPdf2.LastErrorText
    RELEASE loJson
    RELEASE loJsonOut
    RELEASE loInfo
    RELEASE loPdf1
    RELEASE loPdf2
    CANCEL
ENDIF

loPdf2.UserPassword = "user-secret"
loPdf2.OwnerPassword = "owner-secret"
loJson.UpdateString("algorithmChoice","aes-128")
lnSuccess = loPdf2.Protection("encrypt",loJson,loJsonOut)
IF (lnSuccess = 0) THEN
    ? loPdf2.LastErrorText
    RELEASE loJson
    RELEASE loJsonOut
    RELEASE loInfo
    RELEASE loPdf1
    RELEASE loPdf2
    CANCEL
ENDIF

? "aes-128 will be saved as PDF " + loJsonOut.StringOf("pending.pdfVersion")
lnSuccess = loPdf2.WriteFile("qa_output/memo_aes128.pdf")
IF (lnSuccess = 0) THEN
    ? loPdf2.LastErrorText
    RELEASE loJson
    RELEASE loJsonOut
    RELEASE loInfo
    RELEASE loPdf1
    RELEASE loPdf2
    CANCEL
ENDIF

lnSuccess = loPdf2.PreLoadCheck("qa_output/memo_aes128.pdf",loInfo)
IF (lnSuccess = 0) THEN
    ? loPdf2.LastErrorText
    RELEASE loJson
    RELEASE loJsonOut
    RELEASE loInfo
    RELEASE loPdf1
    RELEASE loPdf2
    CANCEL
ENDIF

? "  saved file: " + loInfo.StringOf("algorithm") + ", PDF " + loInfo.StringOf("pdfVersion")

*  RC4-128, a broken cipher, only for readers too old for AES.  Saved as PDF 1.4.
loPdf3 = CreateObject('Chilkat.Pdf')
lnSuccess = loPdf3.LoadFile("qa_data/pdf/two_page_memo.pdf")
IF (lnSuccess = 0) THEN
    ? loPdf3.LastErrorText
    RELEASE loJson
    RELEASE loJsonOut
    RELEASE loInfo
    RELEASE loPdf1
    RELEASE loPdf2
    RELEASE loPdf3
    CANCEL
ENDIF

loPdf3.UserPassword = "user-secret"
loPdf3.OwnerPassword = "owner-secret"
loJson.UpdateString("algorithmChoice","rc4-128")
lnSuccess = loPdf3.Protection("encrypt",loJson,loJsonOut)
IF (lnSuccess = 0) THEN
    ? loPdf3.LastErrorText
    RELEASE loJson
    RELEASE loJsonOut
    RELEASE loInfo
    RELEASE loPdf1
    RELEASE loPdf2
    RELEASE loPdf3
    CANCEL
ENDIF

? "rc4-128 will be saved as PDF " + loJsonOut.StringOf("pending.pdfVersion")
lnSuccess = loPdf3.WriteFile("qa_output/memo_rc4_128.pdf")
IF (lnSuccess = 0) THEN
    ? loPdf3.LastErrorText
    RELEASE loJson
    RELEASE loJsonOut
    RELEASE loInfo
    RELEASE loPdf1
    RELEASE loPdf2
    RELEASE loPdf3
    CANCEL
ENDIF

lnSuccess = loPdf3.PreLoadCheck("qa_output/memo_rc4_128.pdf",loInfo)
IF (lnSuccess = 0) THEN
    ? loPdf3.LastErrorText
    RELEASE loJson
    RELEASE loJsonOut
    RELEASE loInfo
    RELEASE loPdf1
    RELEASE loPdf2
    RELEASE loPdf3
    CANCEL
ENDIF

? "  saved file: " + loInfo.StringOf("algorithm") + ", PDF " + loInfo.StringOf("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

RELEASE loJson
RELEASE loJsonOut
RELEASE loInfo
RELEASE loPdf1
RELEASE loPdf2
RELEASE loPdf3