From Halopedia, the Halo wiki
File/lightning-matrix-four/ was a United Nations Space Command publicly available encryption key.
It was used in conjunction with encryption key Red to encrypt and decrypt United Nations Space Command Priority Transmission 09872H-98.
List of appearances
- Halo: The Fall of Reach (First appearance)
- ^ a b Halo: The Fall of Reach, Chapter 23, page 214(2001 paperback); page 245(2010 paperback)