Editing Secret sharing (section)

==Other uses and applications==
A secret-sharing scheme can secure a secret over multiple servers and remain recoverable despite multiple server failures. The dealer may act as several distinct participants, distributing the shares among the participants. Each share may be stored on a different server, but the dealer can recover the secret even if several servers break down as long as they can recover at least ''t'' shares; however, [[Security cracking|cracker]]s that break into one server would still not know the secret as long as fewer than ''t'' shares are stored on each server.

This is one of the major concepts behind the [[Vanish (computer science)|Vanish]] computer project at the [[University of Washington]], where a random key is used to encrypt data, and the key is distributed as a secret across several nodes in a [[Peer-to-peer|P2P]] network. In order to decrypt the message, at least ''t'' nodes on the network must be accessible; the principle for this particular project being that the number of secret-sharing nodes on the network will decrease naturally over time, therefore causing the secret to eventually ''vanish''. However, the network is vulnerable to a [[Sybil attack]], thus making Vanish insecure.<ref>{{cite web | url=http://z.cs.utexas.edu/users/osa/unvanish/home | title = Unvanish: Reconstructing Self-Destructing Data |url-status=dead |archive-url=https://web.archive.org/web/20120320161926/http://z.cs.utexas.edu/users/osa/unvanish/home |archive-date=2012-03-20}}</ref>

Any shareholder who ever has enough information to decrypt the content at any point is able to take and store a copy of X. Consequently, although tools and techniques such as Vanish can make data irrecoverable within their own system after a time, it is not possible to force the deletion of data once a malicious user has seen it. This is one of the leading conundrums of [[digital rights management]].

A dealer could send ''t'' shares, all of which are necessary to recover the original secret, to a single recipient. An attacker would have to intercept all ''t'' shares to recover the secret, a task which is more difficult than intercepting a single file, especially if the shares are sent using different media (e.g. some over the [[Internet]], some mailed on [[Compact Disc|CD]]s).

For large secrets, it may be more efficient to encrypt the secret and then distribute the key using secret sharing.

Secret sharing is an important primitive in several protocols for [[secure multiparty computation]].
Secret sharing can also be used for user authentication in a system.<ref>Gupta, Kishor Datta, et al. "Shamir's Secret Sharing for Authentication without Reconstructing Password." 2020 10th Annual Computing and Communication Workshop and Conference (CCWC). IEEE, 2020.</ref>