v12.sh/blog/the-case-of-the-9bit-aes-key The case of the 9 bit AES key
Researchers found that several PDF tools generate AES-256 file keys from tiny, enumerable state spaces. MuPDF's key depends on only 9 timestamp bits, while Foxit hashes the current time, so protected files can be decrypted without a password in milliseconds or seconds.
— via Hacker News (top 30), ledoge
