Claude Fable 5.1 Cracks 373-Year-Old Unsolved Cipher

Vals AI reported that Anthropic's Fable 5.1 autonomously chose to solve a 373-year-old cipher ranked among the world's top 50 unsolved encrypted messages, taking 44 minutes and 176k tokens.

2026-09-02 ~ 2026-09-02 · 3 related posts

• Claude Fable 5.1 reportedly cracks a 373-year-old unsolved cipher — RusselTheBrickLayer · 2026-09-02
• Fable 5.1 spontaneously solves 373-year-old cipher in 44 minutes — rickasaurus · 2026-09-02
• Fable 5.1 Helps Crack 373-Year-Old Cipher; Solution Deemed Simple — ethanniser · 2026-09-02