TSM Security Model

From a security point of view the core idea is that all cryptographic keys are split across a set of separate parties called MPC nodes. Each MPC node will only have a share of the key, which in itself reveals no information about the key, yet together multiple MPC nodes are able to perform cryptographic operations without learning anything but their own key share. This is possible by using a a cryptographic technique known as Multiparty Computation.

This approach is also known as Threshold Cryptography, and the idea is that a given TSM is configured with two parameters t and n:

• n is the total number of nodes
• t is the threshold value and the system tolerates up to t corrupt nodes, meaning that at least t+1 nodes are required to perform any operation
• We call this a (n,t)-TSM

Any instance of the Blockdaemon Builder Vault TSM will work with a specific choice of parameters for t and n. Typical values are

• (3,1) meaning that there are three MPC nodes and any two will control the TSM
• (2,1) meaning that there are two MPC nodes and both are needed to control the TSM

The default configuration is a (3,1)-TSM.