The second key escrow technique is secret sharing of key material (either session keys or private keys). Suppose that Alice does not wish to disclose her secret key to anyone directly, but does feel that it would be okay for at least five of her 10 friends to decrypt her messages (perhaps she is worried about disposition of her secret inventions after her death; or maybe just about the possibility that she will lose her original private key). In government proposals the same structure is suggested: In the presence of a warrant, multiple non-government agencies would disclose citizens' shared-secret keys. The latter case is politically troubling, but the cryptographic issue is the same in both cases.

Alice can use a (5,10)-threshold scheme to divide her key among her 10 friends. No one except Alice has access to the whole private key, but five friends can recover it by working together (and thereafter decrypt any messages Alice has encrypted using the key). More complex threshold schemes can also be used if the requirements for key revelation are more structured than this. As mentioned earlier, using a threshold scheme for key escrow is consistent with using session keys; depending on the requirement, it might be a message session key rather than Alice's long-term private key that gets distributed in such a scheme.