Editing Random oracle (section)

== Domain separation ==
{{main|Domain separation}}
A single oracle may be treated as multiple oracles by pre-pending a fixed bit-string to the beginning of each query (e.g., queries formatted as "1||x" or "0||x" can be considered as calls to two separate random oracles, similarly "00||x", "01||x", "10||x" and "11||x" can be used to represent calls to four separate random oracles). This practice is usually called [[domain separation]]. ''Oracle cloning'' is the re-use of the once-constructed random oracle within the same proof (this in practice corresponds to the multiple uses of the same [[cryptographic hash]] within one algorithm for different purposes).{{sfn|Bellare|Davis|Günther|2020|p=3}} Oracle cloning with improper domain separation breaks security proofs and can lead to successful attacks.{{sfn|Bellare|Davis|Günther|2020|p=4}}