Bign: digital signature and key transport algorithms

What is Bign?

Bign is a digital signature system developed in 2010 and standardized a year later in Belarus. The official standard STB 34.101.45 informally inherits the name Bign while the core signature system tends to be called bign-sign.

BignV1

The bign-sign system follows the Schnorr signature scheme. By truncating the hash part of the signatures, bign-sign makes them quite short: 48, 72, or 96 octets depending on the security level.

Additionally to bign-sign, the first edition of STB 34.101.45 defines the following cryptographic mechanisms:

• bign-curves — elliptic curves as a cryptographic platform: selection strategy, validation, standard curves for 3 security levels;
• bign-keytransport — key transport: public key encryption of symmetric keys.

Bign-curves are conventional Weierstrass curves over large prime finite fields. These curves are used outside of Bign to build protocols of the Diffie-Hellman type.

Bign allows using the same pair of private and public keys both in bign-sign and bign-keytransport. Thus, a single public key certificate can serve both authenticity and confidentiality of the holder.

BignV2

The second version of STB 34.101.45, released in 2013, additionally defines:

• bign-genk — an algorithm for generating ephemeral keys during signature creation to make bign-sign fully deterministic;
• bign-ibs — a Galindo-Garcia-like identity-based signature system;
• PBKDF2 and PBES2 — password-based mechanisms to protect Bign private keys.

What is this repo?

In this repo, we process comments on the current version of Bign, discuss future versions, provide additional supporting material.

The latest releases of Bign can be found at Releases.

Comments and proposals are processed at Issues.