DataFlex Requires Chilkat v11.7.0+

Change the Permissions of an Encrypted PDF

See more PDF Protection Examples

Demonstrates the changePermissions operation, which changes what an encrypted PDF permits and keeps its passwords, algorithm and scope. The JSON takes the same permissions member as the encrypt operation, and a permission that is not mentioned is granted. The operation needs owner rights. For an AES-256 PDF, load with both passwords, because the user password cannot be recovered from the owner password alone. DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoPdf
    Variant vJson
    Handle hoJson
    Variant vJsonOut
    Handle hoJsonOut
    Handle hoReader
    Variant vEmpty
    Handle hoEmpty
    Variant vInfo
    Handle hoInfo
    String sTemp1
    Boolean bTemp1

    Move False To iSuccess

    //  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 encrypted_user_password.pdf

    Get Create (RefClass(cComChilkatPdf)) To hoPdf
    If (Not(IsComObjectCreated(hoPdf))) Begin
        Send CreateComObject of hoPdf
    End

    //  Changing the permissions needs owner rights.  Both passwords are given here, which is what
    //  an AES-256 PDF requires for this operation.
    Set ComUserPassword Of hoPdf To "secret"
    Set ComOwnerPassword Of hoPdf To "owner-secret"
    Get ComLoadFile Of hoPdf "qa_data/pdf/encrypted_user_password.pdf" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoPdf To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  No printing and no copying.  Everything not mentioned is granted.
    Get Create (RefClass(cComChilkatJsonObject)) To hoJson
    If (Not(IsComObjectCreated(hoJson))) Begin
        Send CreateComObject of hoJson
    End
    Get ComUpdateString Of hoJson "permissions.print" "none" To iSuccess
    Get ComUpdateBool Of hoJson "permissions.copy" False To iSuccess

    Get Create (RefClass(cComChilkatJsonObject)) To hoJsonOut
    If (Not(IsComObjectCreated(hoJsonOut))) Begin
        Send CreateComObject of hoJsonOut
    End
    Get pvComObject of hoJson to vJson
    Get pvComObject of hoJsonOut to vJsonOut
    Get ComProtection Of hoPdf "changePermissions" vJson vJsonOut To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoPdf To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComStringOf Of hoJsonOut "pending.permissions.print" To sTemp1
    Showln "print: " sTemp1
    Get ComBoolOf Of hoJsonOut "pending.permissions.copy" To bTemp1
    Showln "copy: " bTemp1
    Get ComBoolOf Of hoJsonOut "pending.permissions.modify" To bTemp1
    Showln "modify: " bTemp1
    Get ComBoolOf Of hoJsonOut "pending.userPasswordRequired" To bTemp1
    Showln "password still needed to open: " bTemp1

    Get ComWriteFile Of hoPdf "qa_output/minutes_no_print.pdf" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoPdf To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  The same user password opens the result, now with the new permissions.
    Get Create (RefClass(cComChilkatPdf)) To hoReader
    If (Not(IsComObjectCreated(hoReader))) Begin
        Send CreateComObject of hoReader
    End
    Set ComUserPassword Of hoReader To "secret"
    Get ComLoadFile Of hoReader "qa_output/minutes_no_print.pdf" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoReader To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get Create (RefClass(cComChilkatJsonObject)) To hoEmpty
    If (Not(IsComObjectCreated(hoEmpty))) Begin
        Send CreateComObject of hoEmpty
    End
    Get Create (RefClass(cComChilkatJsonObject)) To hoInfo
    If (Not(IsComObjectCreated(hoInfo))) Begin
        Send CreateComObject of hoInfo
    End
    Get pvComObject of hoEmpty to vEmpty
    Get pvComObject of hoInfo to vInfo
    Get ComProtection Of hoReader "getInfo" vEmpty vInfo To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoReader To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComStringOf Of hoInfo "loaded.permissions.print" To sTemp1
    Showln "saved file, print: " sTemp1
    Get ComBoolOf Of hoInfo "loaded.permissions.copy" To bTemp1
    Showln "saved file, copy: " bTemp1

    //  Sample output:

    //  print: none
    //  copy: False
    //  modify: True
    //  password still needed to open: True
    //  saved file, print: none
    //  saved file, copy: False


End_Procedure