SCTE 104/35 Codex

SCTE 35 can encrypt the middle of a section, from splice_command_type through E_CRC_32, so only authorized receivers can read it. The encrypted_packet flag marks a message as encrypted, encryption_algorithm names the cipher, and cw_index picks which shared key to use. The outer CRC_32 is computed over the encrypted bytes for transport integrity, while the inner E_CRC_32 confirms a successful decryption.