What is cryptographic secret-splitting?
Secret splitting is a cryptographic technique in Nightingale that breaks a piece of data into two components. Learning one of these components does not reveal half of the data — it actually reveals no information at all. Secret splitting is a technique well known to cryptographic experts, and often known as secret sharing. In the most basic form of secret splitting, a secret is split into shares, which are stored on two servers. The secret can later be reassembled from the shares and used for some cryptographic purpose. The secret is thus protected from compromise in its “stored” state, while becoming available “in transit”. In more advanced forms, such as those employed in Nightingale, the two servers can “simulate” the use of the secret without even reassembling it, thus not exposing the secret at all.
