A descrambler is hardware or software that reverses the deliberate scrambling or encryption of a pay-TV or other protected audio-visual signal so it can be viewed in standard form. In legal practice it is discussed in the context of conditional access, unauthorised decoders and pay‑TV piracy. The term itself is descriptive rather than a defined statutory term; UK and Irish legislation more commonly refer to “decoders”, “unauthorised decoders” or “illicit devices”.
In the UK (England & Wales, Scotland and Northern Ireland), dealing in or using unauthorised descramblers to avoid subscription or service charges can give rise to civil remedies and criminal liability, including under the Conditional Access (Unauthorised Decoders) Regulations 2000 and sections 297 and 297A of the Copyright, Designs and Patents Act 1988 (dishonest reception and unauthorised decoders). Similar prohibitions apply in Ireland under the European Communities (Conditional Access) Regulations 2000. Enforcement commonly targets making, importing, distributing, selling, advertising or possessing for commercial purposes illicit descramblers for satellite, cable, IPTV or streaming services.
Use of authorised descramblers supplied under licence (for example, set‑top boxes or CAMs with valid smartcards) remains lawful. Usage and legal treatment are broadly consistent across the UK and Ireland.