You could instead construct a key by appending two securely-long passphrases together (which will then go through a KDF in any good encryption software). Give e

You could instead construct a key by appending two securely-long passphrases together (which will then go through a KDF in any good encryption software). Give each passphrase half to one person. Recombining them is as simple as typing both of them into the passphrase input in the decryption software.