PDFlibPas: encryption and permissions audit in Delphi

losLab PDF Library ger Delphi- och C++Builder-team en PDF-motor med tillgänglig källkod för skrivbord, server, DLL, ActiveX och Dylib, med inbyggda PDF/A- och PDF/UA-kontroller, PAdES-signering och valbara renderare utan extern PDF-tjänst.

Den här artikeln är skriven för developers building document intake, governance, or support tools that need to explain PDF security state. Den behandlar encryption and permissions audit som produktionsnära dokumentteknik, inte som ett isolerat komponentanrop.

Den praktiska risken är att operators may see a locked document icon but still not know which actions are permitted, which objects are encrypted, or whether policy allows processing. Därför behöver flödet ett skrivet kontrakt, observerbar diagnostik och realistiska regressionsfiler.

Arkitekturbeslut

Report security state before acting on the file. which encrypted documents can be previewed, exported, printed, or routed / how password prompts, credential storage, and retry limits are handled

• which encrypted documents can be previewed, exported, printed, or routed
• how password prompts, credential storage, and retry limits are handled
• whether metadata, attachments, and embedded files must be inspected separately
• which permission combinations block automation or require manual approval

Implementeringsflöde

Convert encryption details into policy findings. Ordningen nedan gör arbetsflödet granskbart för Delphi- och C++Builder-team.

1. open the document through a controlled security-inspection path
2. read encryption details and normalize permissions into application policy names
3. inspect metadata and attachments according to the same security profile
4. present operator decisions as allow, warn, block, or request credentials
5. store a redacted security report with the intake or support record

Valideringsbevis

Security audit fields that matter. Behåll dessa fält tillsammans med utdata eller supportunderlaget.

• algorithm, key length, owner password requirement, user password state, and metadata policy
• permission flags mapped to print, copy, edit, annotate, extract, and form-fill outcomes
• attachment and embedded-file security state
• credential prompt result without storing password values

Permissions are not user-interface hints

A security audit should distinguish encryption algorithm, owner and user password requirements, permission flags, metadata handling, attachment state, and viewer behavior. The result should drive application policy rather than simply display raw bits.

Support package design

Once PDFlibPas is deployed, the most valuable support package is the one that explains the input, profile, output, and exact stage that failed.

• algorithm, key length, owner password requirement, user password state, and metadata policy
• permission flags mapped to print, copy, edit, annotate, extract, and form-fill outcomes
• attachment and embedded-file security state
• credential prompt result without storing password values
• terminology snapshot: encryption, permission flags, metadata, attachments

Tekniska granskningsnoteringar för encryption and permissions audit

Använd dessa granskningsnoteringar för att säkerställa att funktionen har passerat demo-nivån och kan försvaras under leverans, support och kundeskalering.

• Beslut: which encrypted documents can be previewed, exported, printed, or routed. Implementeringspresspunkt: read encryption details and normalize permissions into application policy names. Acceptansbevis: attachment and embedded-file security state. Regressionsutlösare: support logs must never include passwords or derived secret material
• Beslut: how password prompts, credential storage, and retry limits are handled. Implementeringspresspunkt: inspect metadata and attachments according to the same security profile. Acceptansbevis: credential prompt result without storing password values. Regressionsutlösare: viewer permissions can be advisory and should not replace application policy
• Beslut: whether metadata, attachments, and embedded files must be inspected separately. Implementeringspresspunkt: present operator decisions as allow, warn, block, or request credentials. Acceptansbevis: algorithm, key length, owner password requirement, user password state, and metadata policy. Regressionsutlösare: encrypted metadata may prevent routing rules that depend on title or author
• Beslut: which permission combinations block automation or require manual approval. Implementeringspresspunkt: store a redacted security report with the intake or support record. Acceptansbevis: permission flags mapped to print, copy, edit, annotate, extract, and form-fill outcomes. Regressionsutlösare: attachments can carry sensitive data not visible on document pages
• Beslut: which encrypted documents can be previewed, exported, printed, or routed. Implementeringspresspunkt: open the document through a controlled security-inspection path. Acceptansbevis: attachment and embedded-file security state. Regressionsutlösare: support logs must never include passwords or derived secret material
• Beslut: how password prompts, credential storage, and retry limits are handled. Implementeringspresspunkt: read encryption details and normalize permissions into application policy names. Acceptansbevis: credential prompt result without storing password values. Regressionsutlösare: viewer permissions can be advisory and should not replace application policy

Gränsfall

• viewer permissions can be advisory and should not replace application policy
• encrypted metadata may prevent routing rules that depend on title or author
• attachments can carry sensitive data not visible on document pages
• support logs must never include passwords or derived secret material

Delphi / C++Builder notes

PDFlibPas should sit behind a small service boundary that receives files, streams, profiles, and credentials, then returns output paths, warnings, metrics, and validation status. Important terms include encryption, permission flags, metadata, attachments, owner password, audit report.

Delphi-kodexempel

Följande Delphi-skiss visar en praktisk servicegräns för detta ämne. Håll policykontroller, loggning och validering utanför det smala produktanropet så att arbetsflödet går att testa.

procedure AuditEncryptionPolicy(const InputFile, OutputFile: string; const Policy: TEncryptionPolicy);
var
  Pdf: TPDFlib;
begin
  Pdf := TPDFlib.Create;
  try
    Pdf.EncryptFile(InputFile, OutputFile, Policy.OwnerPassword, Policy.UserPassword,
      Policy.Strength, Policy.Permissions);
    WriteEncryptionAudit(OutputFile, Pdf.EncryptionAlgorithm, Policy.Permissions);
  finally
    Pdf.Free;
  end;
end;

Produktionschecklista

• Kör arbetsflödet på en tom fil, en normal kundfil och en värstafallfil
• Öppna den genererade PDF-filen med rätt visare, validator, skrivare eller nedströmsapplikation
• Logga produktversion, profilversion, inmatningshash, utdatasökväg, förfluten tid och antal varningar
• Håll lösenord, certifikat, tillfälliga filer och kunddata under tydliga lagringsregler
• Lägg till regressionsdokument när en kundfil avslöjar ett nytt gränsfall

Produktdokumentation

PDFlibPas

Fler kodexempel

var
  PDF: TPDFlib;
  R: Integer;
begin
  PDF := TPDFlib.Create;
  try
    R := PDF.EncryptFile('in.pdf', 'out.pdf', 'owner-secret', 'user-secret', 4,
      PDF.EncodePermissions(1, 0, 0, 0,    // print allowed; copy/change/notes denied
                            0, 0, 0, 1));  // extended set: full-quality print only
    if (R = 1) and (PDF.LoadFromFile('out.pdf', 'user-secret') = 1) then
    begin
      Writeln('algorithm = ', PDF.EncryptionAlgorithm);
      Writeln('strength  = ', PDF.EncryptionStrength);
      Writeln('owner pw accepted: ', PDF.CheckPassword('owner-secret'));
    end;
  finally
    PDF.Free;
  end;
end;

if not Doc.Encrypt('owner-secret', 'user-secret', esAES256BitAcroX,
  [ppCanPrint], [ppCanPrintFull]) then
  raise Exception.Create('Encryption failed');