"liveness." YourDictionary, n.d. Web. 14 January 2019. <https://www.yourdictionary.com/liveness>.
liveness. (n.d.). Retrieved January 14th, 2019, from https://www.yourdictionary.com/liveness
liveness - Computer Definition
In information security, liveness refers to the transmission of data that is happening now and not a replay of a recording of data sent previously. Liveness is introduced into secure transmissions by mixing in a number that cannot be duplicated again (see nonce). See replay attack.