System and method for enforcement of correctness for key derivation

A system for enforcing correctness of a derivation key, comprising:

• multiple computerized nodes configured to store a share of a key used as an input of a function generating the derivation key, a communication module configured to exchange information between the multiple computerized nodes, said multiple computerized nodes are implemented in computer hardware and configured to perform a set of instructions, comprising:
• receiving a request to create the derivation key;
• performing a multiparty computation (MPC) process between the multiple computerized nodes, said MPC process is performed multiple times, in each time the MPC process comprises:
• (a) receiving the key shares as input,
• (b) randomly selecting a function from a plurality of optional functions, wherein the multiple computerized nodes are not aware of the randomly-selected function, wherein one optional function of the plurality of optional functions outputs key shares of the derivation key and another optional function of the plurality of optional functions outputs values that are verifiable by the computerized nodes and
• (c) performing the MPC process using the randomly-selected function, thereby producing outputs of the randomly-selected function;
• providing the outputs of the randomly-selected function to the multiple computerized nodes, the multiple computerized nodes lack access to the selected function;
• wherein in case the another optional function is selected, the multiple computerized nodes perform computations on the received outputs and exchange outputs of the computations to estimate correction of the key shares inputted into the MPC process, and
• wherein the multiple computerized nodes assign the value provided from the MPC process as a key share of the derivation key after checking performance of the optional function that outputs values that are verifiable by the computerized nodes performed by the MPC process, said multiple computerized nodes check performance of the optional function using the commitment message received from another node as input.