PDF를 보호하면 무단 접근을 막고 수신자의 동작을 제어할 수 있습니다.
문제 개요
계약서나 재무 보고서를 이메일로 보낼 때 잘못된 사람이 열지 않도록 해야 합니다.
왜 발생하는가
PDF는 내장 암호화와 권한 플래그를 지원하며 최신 리더가 이를 적용합니다.
단계별 해결 방법
- 1Open a Protect PDF tool and upload the file.
- 2Set a strong user password (to open the file).
- 3Optionally set an owner password to control printing, copying and editing.
- 4Choose the encryption strength — 256-bit AES is recommended.
- 5Save and share the protected file securely; send the password through a separate channel.
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추가 팁
- Use a passphrase of at least 12 characters, mixing words, numbers and symbols.
- Never send the password in the same email as the PDF.
- Store passwords in a password manager so they are not lost.
- Combine with a watermark for extra deterrent against sharing.
자주 묻는 질문
Q.Which encryption should I pick?
256-bit AES. It is the current industry standard.
Q.Can I change the password later?
Yes, unlock the file first then re-protect it with a new password.
Q.Will it still open on phones?
Yes. All mainstream PDF readers support password prompts.
Q.Is protection foolproof?
It stops casual access. Sensitive documents should also use secure delivery.
결론
암호로 보호된 PDF는 잘못된 메일함에 도착해도 안전합니다.
