Visual Basic 6.0 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 Basic 6.0

Dim success As Long
success = 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

Dim json As New ChilkatJsonObject
Dim jsonOut As New ChilkatJsonObject
Dim info As New ChilkatJsonObject

'  AES-256, the default.  Saved as PDF 1.7 with Adobe extension level 8.
Dim pdf1 As New ChilkatPdf
success = pdf1.LoadFile("qa_data/pdf/two_page_memo.pdf")
If (success = 0) Then
    Debug.Print pdf1.LastErrorText
    Exit Sub
End If

pdf1.UserPassword = "user-secret"
pdf1.OwnerPassword = "owner-secret"
success = json.UpdateString("algorithmChoice","aes-256")
success = pdf1.Protection("encrypt",json,jsonOut)
If (success = 0) Then
    Debug.Print pdf1.LastErrorText
    Exit Sub
End If

Debug.Print "aes-256 will be saved as PDF " & jsonOut.StringOf("pending.pdfVersion") & ", Adobe extension level " & jsonOut.IntOf("pending.adobeExtensionLevel")
success = pdf1.WriteFile("qa_output/memo_aes256.pdf")
If (success = 0) Then
    Debug.Print pdf1.LastErrorText
    Exit Sub
End If

success = pdf1.PreLoadCheck("qa_output/memo_aes256.pdf",info)
If (success = 0) Then
    Debug.Print pdf1.LastErrorText
    Exit Sub
End If

Debug.Print "  saved file: " & info.StringOf("algorithm") & ", PDF " & info.StringOf("pdfVersion")

'  AES-128, for readers that predate AES-256.  Saved as PDF 1.6.
Dim pdf2 As New ChilkatPdf
success = pdf2.LoadFile("qa_data/pdf/two_page_memo.pdf")
If (success = 0) Then
    Debug.Print pdf2.LastErrorText
    Exit Sub
End If

pdf2.UserPassword = "user-secret"
pdf2.OwnerPassword = "owner-secret"
success = json.UpdateString("algorithmChoice","aes-128")
success = pdf2.Protection("encrypt",json,jsonOut)
If (success = 0) Then
    Debug.Print pdf2.LastErrorText
    Exit Sub
End If

Debug.Print "aes-128 will be saved as PDF " & jsonOut.StringOf("pending.pdfVersion")
success = pdf2.WriteFile("qa_output/memo_aes128.pdf")
If (success = 0) Then
    Debug.Print pdf2.LastErrorText
    Exit Sub
End If

success = pdf2.PreLoadCheck("qa_output/memo_aes128.pdf",info)
If (success = 0) Then
    Debug.Print pdf2.LastErrorText
    Exit Sub
End If

Debug.Print "  saved file: " & info.StringOf("algorithm") & ", PDF " & info.StringOf("pdfVersion")

'  RC4-128, a broken cipher, only for readers too old for AES.  Saved as PDF 1.4.
Dim pdf3 As New ChilkatPdf
success = pdf3.LoadFile("qa_data/pdf/two_page_memo.pdf")
If (success = 0) Then
    Debug.Print pdf3.LastErrorText
    Exit Sub
End If

pdf3.UserPassword = "user-secret"
pdf3.OwnerPassword = "owner-secret"
success = json.UpdateString("algorithmChoice","rc4-128")
success = pdf3.Protection("encrypt",json,jsonOut)
If (success = 0) Then
    Debug.Print pdf3.LastErrorText
    Exit Sub
End If

Debug.Print "rc4-128 will be saved as PDF " & jsonOut.StringOf("pending.pdfVersion")
success = pdf3.WriteFile("qa_output/memo_rc4_128.pdf")
If (success = 0) Then
    Debug.Print pdf3.LastErrorText
    Exit Sub
End If

success = pdf3.PreLoadCheck("qa_output/memo_rc4_128.pdf",info)
If (success = 0) Then
    Debug.Print pdf3.LastErrorText
    Exit Sub
End If

Debug.Print "  saved file: " & info.StringOf("algorithm") & ", PDF " & info.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