Methods and apparatuses are presented to generate, and verify reception of, ultra wideband (UWB) communications, e.g., to perform secure UWB ranging. Verifier and prover messages may be encoded on top of random cryptographically secure training sequence (STS) of pulses, organized in blocks such that a given block corresponds to a given message bit. In some scenarios, a first STS may be encoded using a verifier message not known to a recipient device. A second STS may be received from the recipient device, encoded with an unknown prover message. A third STS may also be received, encoded with an authentication message generated using the verifier message and the authentication message. Verification of the authentication message can therefore confirm that the recipient device received the first STS, and that the recipient device is the authentic source of the second STS. Thus, the second STS may be relied upon, e.g., for ranging calculations.