Security
The following details how Sygma addresses security concerns relating to various signature schemes.
Threshold Signature Schemes (TSS) is an area of MPC that is particularly useful for the crypto domain as it facilitates the distribution of a private key to multiple parties, introducing redundancy for assets management security.
In other words, it enables a set of parties to perform certain cryptographic operations, like signing transactions, while none of them hold a full private key. Instead, the key is split across the parties, and it can only be used only when a subset of those parties — the size of which is larger than a certain threshold— combines their key shares.
When talking about security, MPC algorithms generally provide guarantees based on the threshold number of corrupted parties a system can tolerate. This places TSS in a unique position, as such schemes place control of their robustness directly in the hands of their developers. Furthermore, this allows the system to withstand even a dishonest majority — an extreme state where adversaries can corrupt up to all but one participant.
Instead of relying on Multisigs or other, older ways of key management that either expose relayer identities or introduce easily exploitable single points-of-failure, relayers for Sygma run a secure MPC ceremony each time a user wishes to bridge funds or transfer arbitrary data.
While designing Sygma, we were convinced that having MPC for relayer communication would not only strengthen the overall security of the system but would also significantly reduce fees for the users making the experience much more appealing.