Good eye! That was a typo. It should read as "colon notation". It is just a visual representation of 128 bits (16 bytes) with each byte separated by colon ":".

Good eye! That was a typo. It should read as "colon notation". It is just a visual representation of 128 bits (16 bytes) with each byte separated by colon ":". I have updated the readme with an example. One place where you will see this notation visually is MAC addresses.