From Halopedia, the Halo wiki
UNSC Emergency Priority Order 098831A-1 was a United Nations Space Command transmission that commanded all UNSC personnel to read General Order 098831A-1, more commonly referred to as the Cole Protocol, every single day "by the letter".
It was broadcast sometime during or before 2535 by H.T. Ward, a Fleet Admiral of UNSC Naval Command.
It was encrypted with the code Red, had a public encryption key of file/first light/ and was classified as Restricted under the BGX Directive.