Rainbow

Multivariate signature scheme and NIST finalist, broken in 2022 by a key-recovery attack that ran over a weekend on a laptop.

Core Principles & Analysis

• Ward Beullens recovered a full Rainbow private key in about 53 hours on a standard laptop.
• The break landed while Rainbow was a final-round NIST candidate — weeks before selections were announced.
• Together with SIKE, it is why broken candidates belong in any honest post-quantum registry.

Specifications & Metrics

• FAMILY: Multivariate
• STATUS: Broken
• YEAR: 2022