losLab PDF Library は、Delphi/C++Builder チーム向けにソース提供の PDF エンジンを提供します。デスクトップ、サーバー、DLL、ActiveX、Dylib ワークフローで使え、PDF/A・PDF/UA チェック、PAdES 署名、複数レンダラーを外部 PDF サービスなしで利用できます。
この記事は developers building document intake, governance, or support tools that need to explain PDF security state 向けです。encryption and permissions audit を単なるコンポーネント呼び出しではなく、本番向けのドキュメントエンジニアリングとして扱います。
実務上のリスクは operators may see a locked document icon but still not know which actions are permitted, which objects are encrypted, or whether policy allows processing です。そのため、明確な契約、観測可能な診断、実際の顧客ファイルに近い回帰サンプルが必要です。
アーキテクチャ上の判断
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
実装フロー
Convert encryption details into policy findings. The order below keeps the workflow reviewable for Delphi and C++Builder teams.
- open the document through a controlled security-inspection path
- read encryption details and normalize permissions into application policy names
- inspect metadata and attachments according to the same security profile
- present operator decisions as allow, warn, block, or request credentials
- store a redacted security report with the intake or support record
検証エビデンス
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.
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
Engineering review notes for encryption and permissions audit
Use these review notes to make sure the feature has moved beyond a demo and can be defended during release, support, and customer escalation.
- Decision: which encrypted documents can be previewed, exported, printed, or routed. Implementation pressure point: read encryption details and normalize permissions into application policy names. Acceptance evidence: attachment and embedded-file security state. Regression trigger: support logs must never include passwords or derived secret material
- Decision: how password prompts, credential storage, and retry limits are handled. Implementation pressure point: inspect metadata and attachments according to the same security profile. Acceptance evidence: credential prompt result without storing password values. Regression trigger: viewer permissions can be advisory and should not replace application policy
- Decision: whether metadata, attachments, and embedded files must be inspected separately. Implementation pressure point: present operator decisions as allow, warn, block, or request credentials. Acceptance evidence: algorithm, key length, owner password requirement, user password state, and metadata policy. Regression trigger: encrypted metadata may prevent routing rules that depend on title or author
- Decision: which permission combinations block automation or require manual approval. Implementation pressure point: store a redacted security report with the intake or support record. Acceptance evidence: permission flags mapped to print, copy, edit, annotate, extract, and form-fill outcomes. Regression trigger: attachments can carry sensitive data not visible on document pages
- Decision: which encrypted documents can be previewed, exported, printed, or routed. Implementation pressure point: open the document through a controlled security-inspection path. Acceptance evidence: attachment and embedded-file security state. Regression trigger: support logs must never include passwords or derived secret material
- Decision: how password prompts, credential storage, and retry limits are handled. Implementation pressure point: read encryption details and normalize permissions into application policy names. Acceptance evidence: credential prompt result without storing password values. Regression trigger: viewer permissions can be advisory and should not replace application policy
境界ケース
- 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 コード例
次の Delphi スケッチは、このテーマに対する実用的なサービス境界を示します。ポリシー確認、ログ記録、検証を製品呼び出しの狭い部分の外側に置くと、ワークフローをテストしやすくなります。
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;本番チェックリスト
- Run the workflow on an empty file, a normal customer file, and a worst-case file
- Open the generated PDF with the target viewer, validator, printer, or downstream application
- Log product version, profile version, input hash, output path, elapsed time, and warning count
- Keep passwords, certificates, temporary files, and customer data under explicit retention rules
- Add regression documents when a customer file exposes a new edge case