A random or pseudorandom sequence of characters added to an encryption key to enhance security. An initialization vector (IV) complicates determining patterns in a series of data containing cryptographic signatures, and makes it more resistant to hacking.
The IV does not require encryption and is usually transmitted along with the cryptographic key. Sometimes the IV is generated according to certain rules based on the signature itself. In this case, there is no need to transfer the IV to the recipient, since the latter can recover it independently.