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Share deletion or corruption

As described in section 3.2, when a document is successfully published a copy of the encrypted document and a share are stored on each of the n servers. Only one copy of the encrypted document and k shares are required to recover the original document. Clearly, if all n copies of the encrypted file are deleted, corrupted or otherwise unretrievable then it is impossible to recover the original document. Similarly if n-k+1 shares are deleted, corrupted or cannot be retrieved it is impossible to recover the key. In either case the published document is effectively censored. This naturally leads to the conclusion that the more we increase n, or decrease k, the harder we make it for an individual, or group of individuals, to censor a published document.

Avi Rubin
2000-06-13