Editing ISDB (section)

===Interfaces and Encryption===
The ISDB specification describes a lot of (network) interfaces, but most importantly, the Common Interface for Conditional Access System (CAS). While ISDB has examples of implementing various kinds of CAS systems, in Japan, a CAS system called "B-CAS" is used. ARIB STD-B25 defines the [[Common Scrambling Algorithm]] (CSA) system called [[MULTI2]] required for (de-)scrambling television.

The ISDB CAS system in Japan is operated by a company named ''[[B-CAS]]''; the CAS card is called ''B-CAS card''. The Japanese ISDB signal is always encrypted by the B-CAS system even if it is a free television program. That is why it is commonly called "Pay per view system without charge".{{Citation needed|date=September 2008}} An interface for mobile reception is under consideration.{{Citation needed|date=September 2008}}

ISDB supports RMP (Rights management and protection). Since all digital television (DTV) systems carry digital data content, a [[DVD]] or high-definition (HD) recorder could easily copy content losslessly.
[[Major film studios|US major film studios]] requested copy protection; this was the main reason for RMP being mandated. The content has three modes: "copy once", "copy free" and "copy never". In "copy once" mode, a program can be stored on a hard disk recorder, but cannot be further copied; only moved to another copy-protected media—and this move operation will mark the content "copy one generation", which is mandated to prevent further copying permanently. "Copy never" programs may only be [[Time shifting|timeshifted]] and cannot be permanently stored. In 2006,<ref name=":0" /> the Japanese government is evaluating using the [[Digital Transmission Content Protection]] (DTCP) "Encryption plus Non-Assertion" mechanism to allow making multiple copies of digital content between compliant devices.<ref name=":0">{{Cite web|url=https://japan.cnet.com/article/20094312/|title=JEITA、地デジのコンテンツ保護策として暗号方式 EPN を提案|date=January 12, 2006|website=CNET Japan}}</ref>