Out of band
Out of band (Eng. "Outside the band") is an English term that describes data in communication that are transmitted outside of the main form of communication. The term band is taken from the field of radio traffic , where frequency ranges are also referred to as band.
Examples
Authentication
Here security information is often transmitted on a second channel, such as B. in telebanking over the Internet , where the security code is transmitted in parallel as an SMS . This is based on the assumption that an attacker cannot eavesdrop on all communication channels of the sender and recipient of a confidential message at the same time or, if they do, it becomes at least more difficult to combine what has been eavesdropped into an attack.
Computer science
In a computer network one describes data that should not be processed within the normal data stream, because they are e.g. B. are particularly urgent, as out-of-band data .