✓ AI summary
Summary of reporting by Hacker News — Front Page • • 1 min read
4 Wire-neutral provisional

✓ No loaded language, vague sourcing, or framing detected.

Insecure Randomness in PDF Implementations Compromises AES-256 Encryption

Research has revealed that several PDF implementations claiming AES-256 encryption generate keys from insecure random sources. MuPDF and Foxit are among those found to have vulnerabilities that could allow for passwordless decryption of protected PDFs. These weaknesses stem from limited randomness in key generation processes, undermining the security of the AES-256 standard.

Companies
MuPDF Foxit

Recent findings indicate that multiple PDF software implementations, including MuPDF and Foxit, generate AES-256 encryption keys from insecure random sources, compromising their security. MuPDF's method uses only 9 bits of randomness, while Foxit's relies on uninitialized bytes, making keys easy to recover. Although some vulnerabilities have been addressed, previously published documents may still be at risk of passwordless decryption.

Key facts

  • MuPDF generates AES-256 keys from only 9 bits of random state.
  • Foxit PDF Reader derives its file key from time-based randomness.
  • AES-256 encryption protects PDF content but does not encrypt documents directly.
  • Vulnerabilities in random number generation can lead to passwordless decryption.
  • Issues have been reported to vendors, with some fixes implemented.
Read the full story at Hacker News — Front Page

A short AI summary in our own words. The reporting belongs to Hacker News — Front Page; we don't reproduce it.

Annotating as

No note attached

on this article.

Original vs. Neutral

Original Headline

The case of the 9 bit AES key

Neutral Headline

Insecure Randomness in PDF Implementations Compromises AES-256 Encryption