SCTE 104/35 Codex

SCTE 35 Part 1

encryption_algorithm

Enumerated values

Clause citations

ValueDecNameDescriptionHistoryRelated
0x000No encryptionThe section is sent in the clear. This is the normal case, since SCTE 35 encryption is optional and rarely used in practice.
0x011DES-ECBDES in Electronic Codebook mode. Encrypts the section from splice_command_type through E_CRC_32 in independent 8-byte blocks under a fixed 64-bit key.
0x022DES-CBCDES in Cipher Block Chaining mode. The same cipher as ECB, but each block is XORed with the previous ciphertext (the first block against a zero initialization vector), so repeated plaintext does not produce repeated ciphertext.
0x033Triple DES EDE3-ECBTriple DES in encrypt-decrypt-encrypt mode with three 64-bit keys, applied per 8-byte block. Stronger than single DES but considerably slower. Its underlying FIPS publication has been withdrawn, so it is not recommended for new designs.
0x04-0x1FReservedReserved for future standardization. Not currently assigned to any algorithm.
0x20-0x3FUser privateA range set aside for private, out-of-band algorithms agreed between sender and receiver. How such an algorithm is chosen and registered is outside the scope of the standard.