> For the complete documentation index, see [llms.txt](https://docs.lightlink.io/lightlink-protocol/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.lightlink.io/lightlink-protocol/building-on-lightlink/boneh-lynn-shacham-signatures-bls.md).

# Boneh-Lynn-Shacham Signatures (BLS)

BLS (Boneh-Lynn-Shacham) is a cryptographic signature scheme that allows a user to verify the authenticity of the signer. This process utilizes bilinear pairings and elliptic curves to generate and aggregate signatures for blocks and transactions. BLS enables the protocol to combine multiple signatures into one while maintaining the traceability of the original signatures.

BLS is used for signing the Replicator nodes' proofs for transactions and blocks. The aggregation of signatures helps save block space, reduces time, and decreases the computational power required to validate the necessary number of proofs. This efficiency allows LightLink to operate with a 500 ms block time and approximately $0.01 per transaction fee.

LightLink supports the most popular curves for BLS, including:

* ecrecover
* sha256hash
* ripemd160hash
* dataCopy
* bigModExp
* bn256AddIstanbul
* bn256ScalarMulIstanbul
* bn256PairingIstanbul
* blake2F

Learn more about [BLS usage in L2s](https://mirror.xyz/0x6afeB3d9E380787e7D0a17Fc3CA764Bb885014FA/D3g-4UPRLkAnug-p6AZYfjgXWo-psaTulyu3SaL35vg).


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