ANSI SCTE 52-2018 pdf free download – Data Encryption Standard – Cipher Block Chaining Packet Encryption Specification.
1.0 SCOPE
This document is identical to SCTE 52 2013 except for informative components which may have been updated such as the title page, NOTICE text, headers and footers. No normative changes have been made to this document.
1.1 Purpose
This document defines a method for encrypting MPEG-2 transport stream packets using the Data Encryption Standard (DES) Cipher Block Chaining (CBC) encryption standard.
1.2 Organization
The sections of this document are organized as follows:
• Section 1 — Provides this general introduction.
• Section 2 — Lists applicable documents.
• Section 3 — Provides a list of acronyms and abbreviations used in this document.
• Section 4 — Discusses packet encryption.
• Appendix A — Provides examples of different Cipher Block termination methods.
2.0REFERENCES2.1
Normative References
The following documents contain provisions, which, through reference in this text,constitute provisions of the standard.At the time of Subcommittee approval, theeditions indicated were valid. All standards are subject to revision; and while partiesto any agreement based on this standard are encouraged to investigate the possibilityof applying the most recent editions of the documents listed below, they are
reminded that newer editions of those documents may not be compatible with thereferenced version.
1. Federal Information Processing Standards Publication (FIPS PUB)46-3t, Data
Encryption Standard (DES); specifies the use of Triple DES, available at
http://csrc.nist.gov/publications/PubsFIPSArch.html
2. FIPS PUB 74*, Guidclines for Implementing and Using the National Bureau of
Standards (NBS) Data Encryption Standard, available at
http;://csrc.nist.gov/publications/PubsFIPSArch.html3. FIPS PUB 81, DES Modcs of Operation, available at
http://csrc.nist.gov/publications/PubsFIPSArch.html
4. ISO/IEC 13818-1:2013 |ITU-T Rec.H.222.0 Information technology -Generic
coding of moving pictures and associated audio information: Systems
2.2 Informative Rcferences
The following documents may provide valuable information to the reader but are notrequired when complying with this standard.
5. NBS PUB 500-20, Validating the Correctness of Hardware Implementations of the
NBS Data Encryption Standard
4.0 PACKET ENCRYPTION SPECIFICATION 4.1 Use of DES CBC for MPEG-2 Transport Stream Packet Payloads The DES CBC packet encryption methods explained in this standard, and used for MPEG-2 transport stream packets SHALL comply with the scrambling requirements defined in ISO/IEC 13818-1 [5]. Of primary importance in [5] for this standard is the requirement that only MPEG-2 transport stream packet payloads are to be encrypted (or decrypted). That is, the MPEG-2 transport packet header and the adaptation field of the packet, when present, are not to be encrypted (or decrypted).
4.2 Basic DES Cipher Block Chaining DES packet encryption permits the encryption and decryption of packet data such as audio, video, or data. This is performed using DES Cipher Block Chaining, as specified in [2], pg. 16 and [3], pg. 5. Figure 2 shows basic DES CBC, which SHALL be used to encrypt and decrypt packet payloads that contain an integer number of 8-byte blocks.
Note the exception handling of a small block of data less than 8 bytes, following a non- zero number of 8-byte blocks might occur with a packet payload not equal to an integer number of 8-byte blocks such as a payload of an odd length. This is called “termination block processing.” Note that this is not encryption of packet data, but XOR of packet data with a quantity generated by encryption. The 1 to 7 bytes (of the quantity generated by encryption) used for XOR with packet data SHALL be the leftmost. It is similar to Output Feedback Processing in that regard, in that the Encoder and Decoder form identical quantities to XOR on the packet data. This differs from non-termination block (basic DES) CBC, where packet data is encrypted at the encoder and decrypted at the decoder. The DES operation for this mode is encryption in both Encoder and Decoder, not decrypt in one and encrypt in the other. The Residual Termination Block Processing as explained above and illustrated in Figure 3 SHALL be used for packet payloads containing a residual termination block, with less than 8 bytes of data, following a non-zero number of 8-byte blocks.ANSI SCTE 52 pdf download.