-Invented by Dan Boneh, Ben Lynn & Hovav Shacham.
-Makes use of Elliptic Curve Pairings.
Benefits:
- The scheme is simple (despite the inherent complexity in elliptic curve pairings themselves) .
- Deterministic, meaning there is only one possible signature per validator .
- Compatible with threshold signatures, aggregrate sigs and various cryptographic schemes .
- Both signatures or keys can be 32 bytes long.
Boneh-Lynn-Schacham signatures in Ethereum
The BLS scheme is used specifically for validator signatures.
BLS shines in the context of blockchain architectures due to its ability to aggregate signatures.
Let’s imagine a scenario where many validators (computers verifying transactions) need to vote on a new block .
Traditionally, each validator would need to send their individual signature for the vote.
The problem with this approach is that , with a large number of validators , that can become cumbersome, each signature adding to the data being transmitted , slowing down the network.
BLS to the rescue
BLS allows for those validator signatures to be aggregated.
Each validator signs the block with their private key . Iinstead of sending the full signature, they contribute a portion to an aggregate signature; this aggregate signature been much smaller than the sum of individual signatures.