-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, aggregate 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 . Instead 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.
Another useful use case for BLS signatures
In the context of the Ethereum blockchain network and more specifically the ERC-4337 standard concerning the account abstraction architecture , BLS (Boneh-Lynn-Shacham) signatures can be utilized by signature aggregators to enhance the efficiency and scalability of transaction processing.
BLS signatures allow multiple individual signatures to be combined into a single, compact aggregate signature. This significantly reduces the data size and computational overhead required for verifying multiple signatures.
In the ERC-4337 architecture, signature aggregators are optional components . They play a crucial role in validating aggregated signatures, which approve multiple operations in a single step.
By leveraging BLS signatures, aggregators can ensure that the bundled UserOperations are valid, thereby improving the overall performance and security of the transaction processing system.