Is there an encryption algorithm/protocol where any of a pre-defined set of keys/passwords will succeed in decrypting a document? The number of keys can be fixed, say, 10 or 20 possible passwords.
The context is a single application (with a single embedded document), with no server-side component. It should be shareable amongst users, where any password, within a pre-defined set of passwords, will succeed in gaining access (decrypting the document).
EDIT: In thinking about this, can I append a (symmetrically) encrypted key to the document, where the password to decrypt this is a user's password? I.e. for each user, append the master-key after encrypting it with the users password. I'm not sure what algorithm is appropriate here, or whether this is at all secure.
Disclaimer: I'm fairly new to cryptography beyond the basic concepts and implementations - I don't know the terminology very well, and therefore I was unable to find a similar question posted.