What is a Shard?
In a blockchain network, a shard is a self-sufficient piece of the larger network that contains a subset of the network’s data.
In blockchain networks, sharding is the process of dividing a network into smaller, more manageable parts. The resulting parts are called shards – also known as shares or fragments.
Traditionally, blockchain networks process every transaction on a single chain, which leads to network congestion and lagging transactions or slow speeds. The goal of sharding in blockchains is to improve overall performance and efficiency, as well as address scalability issues without sacrificing the network’s decentralization. Sharding minimizes the burden laid upon individual components within a blockchain network.
Sharding can also be applied to private keys to manage access to cryptocurrency assets and wallets.
Shards and Private Keys
Sharding can be used to split the pre-BIP39 (the entropy used to produce the recovery phrase) version of the private keys. So every fragment represents a “share” of the private keys. Each share is part of a secret and individually, the fragments are useless on their own.
Assuming that there are 3 shares, a threshold of 2 out of 3 of the shards have to be reassembled to reconstruct the private key to access your wallet. This makes it difficult to compromise the security of your wallet and digital assets.
Sharding private keys removes the risk of a single point of failure, as opposed to keeping the secret recovery phrase as a whole.
Technically, the more the number of shards or encrypted fragments, the more secure the private key is. To understand how Ledger incorporates sharding in private keys, check out how Ledger Recover securely distributes the shares.