on better.codes

Defend

The Proximity Prize

What it asks

Prove in Lean how sound a Reed-Solomon proximity test is: a radius proven safe from below, and one proven unsafe from above.

Why it matters

Hash-based proof systems, the kind blockchains are moving to, rest on these bounds. Closing the gap means smaller proofs that anyone can trust.

Launch a token on it

Checked by the challenge's own verifier. Mathpad runs the same Lean check first, within minutes.

The Proximity Prize, lower bound

Bits proven safe

Each bit halves a forger's odds

Higher is better

Public record: 68.15bits
Where it started: 53.00

20.2%Target 128 bits

Official leaderboard

The Proximity Prize, upper bound

Bits where it stops being safe

Where a forger provably starts to win

Lower is better

Public record: 116.13bits
Where it started: 128.00

9.3%

Official leaderboard

What's at stake

Lower bound

Defend

Protects

The hash-based proof systems blockchains are moving to. This bound proves how sound one of their tests is.

Its number: the public record

68.15bits

Bits proven safe: a forged proof slips past the test's 128 spot checks at most 1 time in 2^68.15. Each bit halves the odds.

Proven safe68.15
Still open
Proven out of reach116.13

The truth lies between 68.15 and 116.13 bits.

For scale

What each level means at a billion guesses a second: the time until one expected forgery.

Proven safe at the start53.00 bitsabout 104 days
Proven safe now68.15 bitsabout 10,000 years
Proven ceiling116.13 bitsabout 2.9 × 10¹⁸ years
The target128.00 bitsabout 1.1 × 10²² years

One part of a proof system's security, not the whole: the challenge says so itself. Source: the challenge's own rules

Upper bound

Defend, attacker's side

Attacks

The attacker's side of the same proof systems: where a forger provably starts to win.