Raptor: a lattice based (linkable) ring signature

Raptor signature and Reference Code

Contacts:

• Zhenfei Zhang

Contacts may be reached by sending mail to support@onboardsecurity.com

Project Overview

Raptor (F-22) gets its name from its main building block: Falcon signature.
It is the next generation of Falcon (F-16) featured with a stealth mode.

The Raptor cryptography system consists of two component:

• lattice-based ring signature;
• lattice-based one time linkable ring signature.

Todo list

• signature size compression
• more efficient discrete Gaussian sampler
• replace Karatsuba with NTT
• supporting Falcon-1024
• removing redundancy
• strip out NIST wrapper
• unify the PRNG, XOF, hash, etc
• merge into CryptoNote

FAQ

What is Raptor?

Raptor is an efficient instantiation of lattice based linkable ring signature.
The paper describing this signature scheme is under peer review.

How efficient is Raptor?

Raptor is the only implementable lattice based ring signature to date.
The current characteristics are

Users	5	10	50
KeyGen	57 ms	57 ms	57 ms
Sign	10.7 ms	17.4 ms	61 ms
verification	5.2 ms	11 ms	50 ms

It will be more efficient once I finish the todo list.
The estimated signing time will be of the same level as ECC based solutions, i.e., ~ 1 ms per signature.
The size will be

Users	5	10	50
PK	0.9 KB	0.9 KB	0.9 KB
SK	9.1 KB	9.1 KB	9.1 KB
Signature	8.8 KB	16 KB	73.8 KB

Is Raptor Patented?

The source code is released under GPL.
The Raptor algorithms are covered by the following patents:

• NTRUSIGN
• NTRU/Falcon based chameleon hash plus scheme; TBA
• A new generic framework for ring signature; TBA
• Raptor - instantiation of the framework with NTRU/Falcon

The patents will still be enforced but may be used under the GPL,
i.e. under the condition that any work that uses them is also made available under the GPL.
The patents and the code implementations are also available under standard commercial terms.