science

Viaccess

Viaccess is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Viaccess rather than just read about it. In short: Viaccess is a conditional access system developed by France Télécom, now Orange. There are six versions in use today, Viaccess PC2.3, Viaccess PC2.4, Viaccess PC2.5, Viaccess PC2.6, Viaccess ACS3.x/Prime Sentinel, Viaccess ACS4.1, Viaccess ACS5.0, and Viaccess ACS6.x/Adaptive Sentinel.

Key takeaways

Viaccess belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Viaccess to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Viaccess from memory before moving on to harder problems.

Reference excerpt

Viaccess is a conditional access system developed by France Télécom, now Orange. There are six versions in use today, Viaccess PC2.3, Viaccess PC2.4, Viaccess PC2.5, Viaccess PC2.6, Viaccess ACS3.x/Prime Sentinel, Viaccess ACS4.1, Viaccess ACS5.0, and Viaccess ACS6.x/Adaptive Sentinel. Viaccess was developed as the digital version of the EuroCrypt system used with the hybrid MAC system, The first version is sometimes referred to as Viaccess 1, and the latter three, although different, as Viaccess 2. PC2.3 and PC2.4 are known to be ineffective, and many set-top boxes can be 'patched' to decrypt Viaccess signals without payment, however PC2.5 and PC2.6 are secure, with PC2.5 remaining secure two years after its first commercial deployment. PC2.6 was introduced at the end of 2005. PC3.0 was introduced during mid-2007. There are two modifications of Viaccess PC2.3 in use. The first, known as TPS Crypt, is used by TPS. Despite being compromised also, the TPS Crypt system has been further modified to use Advanced Encryption System (AES) keys. These AES keys were originally updated once weekly, however after this inconvenienced unauthorised viewers little, a second TPS crypt system was introduced, by which keys are changed every 12 minutes, with keys being sent over TPS's internal Open TV system. This therefore meant that only TPS receivers could receive the new AES key, and not the insecure TPS subscription cards. Monitoring and analysing of the keys by hacking groups, however, has brought about key lists, where the AES keys have been successfully predicted. Implementation of this procedure of automatically updating keys has proved difficult, if not impossible, to implement on many satellite receivers, rendering the TPS Crypt AES system a general success. In 2008, Viaccess acquired Orca interactive and in 2012 they merge under the name Viaccess-Orca, which specializes in video content security and anti-piracy, OTT & IPTV platforms and targeted TV advertising. The second Viaccess modification, called ThalesCrypt, is used by Canal Satellite France to protect its contents on the transport network to the head-ends of the cable networks; it is an over-encryption mechanism of the original protocol encryption keys. Viaccess is currently used by a large number of providers. These include:

Team:Media Bosnia Some programs ART NTV Plus Televisa Networks Canal Satellite France FRANSAT AB Sat ETTV TBLTV Home2US Orange TV Romania Orange Polska YouSee Croatian Radiotelevision RTV Slovenija Skylink Czechia/Slovakia SRG SSR idée suisse Cyfrowy Polsat Platforma Canal+ Viaccess is the 3rd largest conditional access system provider in the world (in 2004). Viaccess is also a subsidiary of Orange S.A. which offers pay TV and digital rights management enabled software. Orca Interactive is a subsidiary of Viaccess which offers IPTV Middleware since 2008.

References

External links Viaccess home page

Illustrations

Worked examples

Example 1 — a first encounter with Viaccess

Start with the simplest possible case. Write down what Viaccess claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Viaccess before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Viaccess ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Viaccess

In research: Viaccess appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Viaccess in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Viaccess is common in secondary-school and first-year university syllabi. It links to neighbouring topics Conditional-access television broadcasting, Digital television, so understanding it makes those chapters shorter.
In everyday life: Look for Viaccess outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Viaccess in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Viaccess means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Viaccess out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Viaccess in simple terms?

Why does Viaccess matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Viaccess?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Viaccess.