A client application cryptographically protects application data using an application-layer cryptographic key. The application-layer cryptographic key is derived from cryptographic material provided by a cryptographically protected network connection. The client exchanges the cryptographically protected application data with a service application via the cryptographically protected network connection. The client and service applications acquire matching application-layer cryptographic keys by leveraging shared secrets negotiated as part of establishing the cryptographically protected network connection. The shared secrets may include information that is negotiated as part of establishing a TLS session such as a pre-master secret, master secret, or session key. The application-layer cryptographic keys may be derived in part by applying a key derivation function, a one-way function or a cryptographic hash function to the shared secret information.