DataFlex Requires Chilkat v11.7.0+

Change the Passwords of an Encrypted PDF

See more PDF Protection Examples

Demonstrates the changePasswords operation, which gives an encrypted PDF new user and owner passwords and keeps its algorithm and permissions. The PDF is loaded with its current passwords, the two properties are then set to the new ones, and Protection reads them at the time of the call. Both passwords are replaced, so set both: a property left empty becomes an empty password. DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoPdf
    Variant vJson
    Handle hoJson
    Variant vJsonOut
    Handle hoJsonOut
    Handle hoReader
    Handle hoOwner
    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

    //  Load with the current passwords.
    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

    //  The new passwords.  Protection reads the properties as they are when it is called.
    Set ComUserPassword Of hoPdf To "new-user-secret"
    Set ComOwnerPassword Of hoPdf To "new-owner-secret"

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

    //  The algorithm and the permissions are kept.
    Get ComStringOf Of hoJsonOut "pending.algorithm" To sTemp1
    Showln "algorithm: " sTemp1
    Get ComBoolOf Of hoJsonOut "pending.userPasswordRequired" To bTemp1
    Showln "password needed to open: " bTemp1

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

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

    Get pvComObject of hoJson to vJson
    Get pvComObject of hoJsonOut to vJsonOut
    Get ComProtection Of hoReader "getInfo" vJson vJsonOut To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoReader To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComStringOf Of hoJsonOut "loaded.openedWith" To sTemp1
    Showln "with the new user password, opened with: " sTemp1

    //  And so does the new owner password.
    Get Create (RefClass(cComChilkatPdf)) To hoOwner
    If (Not(IsComObjectCreated(hoOwner))) Begin
        Send CreateComObject of hoOwner
    End
    Set ComOwnerPassword Of hoOwner To "new-owner-secret"
    Get ComLoadFile Of hoOwner "qa_output/minutes_new_passwords.pdf" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoOwner To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get pvComObject of hoJson to vJson
    Get pvComObject of hoJsonOut to vJsonOut
    Get ComProtection Of hoOwner "getInfo" vJson vJsonOut To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoOwner To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComStringOf Of hoJsonOut "loaded.openedWith" To sTemp1
    Showln "with the new owner password, opened with: " sTemp1

    //  Sample output:

    //  algorithm: rc4-128
    //  password needed to open: True
    //  with the new user password, opened with: user
    //  with the new owner password, opened with: owner


End_Procedure