Efficient Weighted Threshold Ecdsa For Securing Bitcoin Wallet

Bitcoin is a digital currency based on cryptographic algorithms. All the transactions of this currency are recorded and stored in a publically available database called blockchain. Since, these transactions are available to everyone, bitcoins must be stored in a secured wallet. These bitcoin wallets can be opened only by its secret key. And if once the secret key of the wallet is lost, it cannot be recovered because of the irreversible nature of bitcoin transaction. To root out this problem, Goldfeder et al. [4] proposed a solution of threshold signature scheme compatible with bitcoins signature by using Elliptic Curve Digital Signature Algorithm (ECDSA) providing security policy of shared control of a wallet in which each player gets only a single share. Considering an important point of priority/weightage of players, Dikshit and Singh [12] first proposed a scheme in which each player is given one or more shares of the secret key according to his weightage/priority. This scheme has a drawback of managing and handling many keys by each player. Suppose a player has weightage w, then he possesses w different shares of secret key. This problem is resolved in the proposed scheme in this paper. We propose a scheme in which all the players get single share and can accomplish the requirements of concept of weightage. We extend the weighted threshold ECDSA scheme in order to realize efficient weighted threshold ECDSA scheme.