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기술 문서

PDFlibPas: Delphi에서 encryption and permissions audit

Delphi PDF Library

losLab PDF Library는 Delphi 및 C++Builder 팀에 소스 제공 PDF 엔진을 제공합니다. 데스크톱, 서버, DLL, ActiveX, Dylib 워크플로에서 PDF/A 및 PDF/UA 검사, PAdES 서명 지원, 렌더러 선택을 외부 PDF 서비스 없이 사용할 수 있습니다.

이 글은 developers building document intake, governance, or support tools that need to explain PDF security state을 위한 글입니다. encryption and permissions audit을 단순한 컴포넌트 호출이 아니라 운영 환경의 문서 엔지니어링으로 다룹니다.

실제 위험은 operators may see a locked document icon but still not know which actions are permitted, which objects are encrypted, or whether policy allows processing입니다. 따라서 명확한 계약, 관찰 가능한 진단, 실제 고객 파일을 반영한 회귀 샘플이 필요합니다.

아키텍처 결정

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

구현 흐름

Convert encryption details into policy findings. The order below keeps the workflow reviewable for Delphi and C++Builder teams.

  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

검증 증거

Security audit fields that matter. Keep these fields with the output or support record.

  • 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.

지원 패키지 설계

PDFlibPas가 배포된 후 가장 유용한 지원 패키지는 입력, 프로필, 출력, 그리고 실패한 정확한 단계를 설명하는 것입니다

  • 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

encryption and permissions audit에 대한 엔지니어링 검토 노트

이 검토 노트를 사용해 기능이 데모 단계를 넘어섰고 출시, 지원, 고객 에스컬레이션 상황에서 설명할 수 있는지 확인합니다

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

경계 사례

  • 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 참고 사항

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

Delphi 코드 예제

다음 Delphi 스케치는 이 주제에 맞는 실무형 서비스 경계를 보여 줍니다. 정책 검사, 로깅, 검증을 좁은 제품 호출 구간 밖에 두면 워크플로를 테스트하기 쉽습니다.

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;

운영 체크리스트

  • 워크플로는 빈 파일, 일반 고객 파일, 최악의 파일에서 실행합니다
  • 생성된 PDF는 대상 뷰어, 검증기, 프린터 또는 downstream 애플리케이션에서 엽니다
  • 제품 버전, 프로필 버전, 입력 해시, 출력 경로, 경과 시간, 경고 수를 기록합니다
  • 암호, 인증서, 임시 파일, 고객 데이터는 명확한 보존 규칙에 따라 관리합니다
  • 고객 파일이 새로운 경계 사례를 드러내면 회귀 문서를 추가합니다

제품 문서

PDFlibPas

추가 코드 예제

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');