HATCHA

HATCHA CAPTCHA proves you're human. HATCHA proves you're not. HATCHA H yperfast A gent T est for C omputational H euristic A ssessment is a reverse CAPTCHA that gates access behind challenges trivial for AI agents but painful for humans — large-number multiplication, string reversal, binary...

reverse-captcha-eval

Reverse CAPTCHA: Evaluating LLM Susceptibility to Invisible Unicode Instruction Injection An evaluation framework that tests whether large language models follow invisible Unicode-encoded instructions embedded in otherwise normal-looking text. Where traditional CAPTCHAs exploit tasks humans can...

Reverse CAPTCHA: Evaluating LLM Susceptibility to Invisible Unicode Instruction Injection

We introduce Reverse CAPTCHA, an evaluation framework that tests whether large language models follow invisible Unicode-encoded instructions embedded in otherwise normal-looking text. Unlike traditional CAPTCHAs that distinguish humans from machines, our benchmark exploits a capability gap: model...