Definition: Rewrite each original sentence in order to make it easier to understand by non-native speakers of English. You can do so by replacing complex words with simpler synonyms (i.e. paraphrasing), deleting unimportant information (i.e. compression), and/or splitting a long complex sentence into several simpler ones. The final simplified sentences need to be grammatical, fluent, and retain the main ideas of their original counterparts without altering their meanings.
Input: The shared secret is either shared beforehand between the communicating parties, in which case it can also be called a pre-shared key.

The secret is either shared before between communicating parties. Then it can also be called a pre-shared key.