Tips for concealing class and alignment in a party with a paladin?

[Jay R]

It doesn't actually say that in any source that I'm familiar with. Closest thing is that "The process of becoming a lich is unspeakably evil" which could mean a bunch of things.

I suppose it could, but it probably means that it's unspeakably evil.

Of course, there's an easy solution there:
"Of course I know how to undergo the lichdom ritual. It's dead easy (if you'll pardon the pun). Any idiot who can hack together a magic talisman, has even the most rudimentary grasp of necromancy, and is willing to sacrifice a hundred innocent souls to *insert evil death god here* can pull it off. I'm trying to work out a way to do it without empowering *insert evil death god here.*."

OK, I'll bite. How does this solve the fact that a Paladin will never associate with evil characters, and the cleric is an evil character?

When the secret gets out the party is permanently broken. That's what needs to be fixed.

Also, definitely talk to the Paladin player OOC, as well as the DM, about this. There might be a way to justify things. Like, if the Paladin and the would-be lich are childhood friends, or the Paladin agrees that, provided a way can be found for the cleric to become a lich without performing unspeakable acts on anything except his own soul, the cleric really would be a better god than the one he's trying to replace.

But the cleric is still Evil, and the Paladin will still not associate with him.

And whatever you wind up doing is not a lich, if it isn't Evil.