An Encryptor is a role that allows people who can converse with it to talk during the Day phase. Otherwise, they are restricted to speaking during the Night phase.
If given to Mafia, an Encryptor is considered Normal on mafiascum.net. Encryptors only affect their own factional chat. Mafia do not need an Encryptor to have daytalk, but if they have it without an Encryptor it needs to be announced beforehand.
Use and Power
Encryptor is a difficult role to quantify the power of. It effectively amplifies the existing coordination skill of the people talking - people who already had no synergy won't get anything out of daytalk; people who are skilled at manipulating the Day game will find it a massive power boost. With that in mind, Encryptor is a potentially large buff to a scumteam - contingent on the scumteam's skill.
Note that including an Encryptor in a Mafia faction that has two members is equivalent to simply giving the faction daytalk outright.