PDF Password Security — Do's and Don'ts
Strong passphrases, channel separation, and limits of visual watermarks.
Published June 4, 2025 · 1 min read
Password-protecting PDFs is easy; doing it safely is harder. Weak passwords fall to offline cracking within hours.
Do
- 12+ random characters or long passphrases
- Share password on a different channel than email
- Rotate passwords when staff leave
Do not
- Put the password in the email subject line
- Use client name + 123
- Assume watermark alone equals security
Sources & references
Primary references used when researching and fact-checking this guide. See our editorial methodology.
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Adobe PDF Reference — encryption
— Adobe
PDF password protection and encryption standards (ISO 32000).