An attacker captures the encrypted communication between two parties for a week, but is unable to decrypt the messages. The attacker then compromises the session key during one exchange and…

Asymmetric encryption uses public and private key pairs for encryption and decryption, but it doesn't inherently prevent a compromised session key from affecting other sessions if those keys are derived from a static secret.

Out-of-band key exchange refers to transmitting a key over a separate, secure channel, which is a method of key exchange but not the principle that prevents decryption of past or future communications after one session key is compromised.

Perfect forward secrecy (PFS) ensures that a compromise of a session key for one communication does not allow an attacker to decrypt previously captured or future communications. This is because PFS uses ephemeral, unique session keys for each communication session, meaning each session's key is independently derived and not dependent on or derivable from a compromised key from another session.

Secure key escrow involves storing encryption keys with a third party for recovery or access purposes, which is unrelated to preventing the compromise of one session key from affecting other communication sessions.