Open or protected: when should a venue broadcast need a code?

Why it matters

The SIG advises encrypting confidential content because the signal can pass through walls¹. Its QR-code paper describes limiting access at meetings and screenings, while RNID warns that obtaining a code can make joining harder or inaccessible for some listeners^2,3.

What the evidence shows

• The signal leaves the room. The SIG's transmitter design guide says confidential content should be encrypted because the signal passes through walls¹. Pro Audito expects many systems to need a PIN, because most people will soon be able to receive streams inside and outside the room⁴.
• How protection works. Encryption covers a whole broadcast: either all its streams use the same Broadcast Code or none are encrypted, and the announcement shows whether a broadcast is encrypted⁵. A transmitter cannot change its code during a broadcast; a new code means stopping and restarting it⁶.
• Getting the code to listeners. The SIG’s assistant guide leaves the method of obtaining a Broadcast Code to the implementation and lists manual entry of a printed code, QR codes, NFC tags and codes passed from a built-in transmitter⁶. A QR code in the standard format must include the code when the streams are encrypted, so listeners need not type it themselves⁷. The SIG suggests codes that change with each showing or meeting, shown on a screen or shelf label², and in Pro Audito’s unpaid test of a transmitter and clip receivers supplied free by the manufacturer, the transmitter sent the PIN wirelessly to the clip receivers when they were switched on⁸.
• Advice on when to use a code differs. A Swiss expert says a PIN is needed only where discretion is required and reception outside the venue is unwanted, should then be new for each event and shown at the entrance, and should be avoided where possible to keep handling simple for technicians and the audience⁹.
• Short codes are weak. Pro Audito notes that four-digit PINs are easy to guess and lists open questions on changing and sharing them⁴.
• A code added no delay in one test. In Pro Audito’s independent test, with products lent free by manufacturers, PIN code protection did not affect latency¹⁰.
• Codes can exclude. RNID warns that password-protected streams risk excluding some people, and finds that at a reception desk a maintained loop still gives people without a smartphone a simpler experience than an encrypted Auracast stream³.
• A shared code cannot establish sender identity against other code holders. A peer-reviewed security paper by researchers at Graz University of Technology and the University of Pisa (funding not stated) explains that encrypted broadcasts can authenticate messages using the shared Broadcast_Code, but an attacker who knows it can impersonate the sender or disrupt the stream. The authors propose an additional mechanism, tested with dummy audio on two development boards, that is not part of the specification¹¹. RNID names spoofed announcement streams as a risk that needs practical trials³.
• Privacy is part of the legal duty. The ADA Title III regulation requires auxiliary aids to be provided in a way that protects the privacy and independence of the person with a disability¹², and the 2024 International Building Code’s model provisions require assistive listening in courtrooms even where no amplification is used, subject to local adoption¹³.
• Swiss sources on discretion. The SIA 500 consultation draft proposes allowing infrared and FM where eavesdropping must be prevented; the draft has no validity and must not be applied¹⁴, and Swiss accessibility guidance says secure Auracast solutions for settings such as courtrooms were still in development in 2025¹⁵.

Where sources disagree

The SIG advises encrypting confidential content and describes per-showing codes as workable^1,2; RNID warns that protected streams risk excluding some listeners³. The Swiss draft standard proposes allowing infrared or FM where eavesdropping must be prevented¹⁴, and Swiss guidance says secure Auracast solutions for settings such as courtrooms were still in development¹⁵. Sources also disagree on how often a code will be needed: Pro Audito's operator guidance expects many systems to need a PIN⁴, while a Swiss expert advises avoiding a PIN where possible⁹. None of the sources reports how many listeners fail to join a protected stream, or how far an open stream is heard outside a room.

What would settle it

User tests of joining protected streams with hearing-aid and implant users would test the exclusion risk RNID identifies³. Measurements beyond room boundaries would quantify the spill the SIG warns about¹. An authentication mechanism adopted into the Bluetooth specification would address the gap identified by the security paper, whose proposed mechanism is not part of the specification¹¹.

Planning while it is open

• Decide room by room whether the content is confidential; the SIG advises encrypting confidential content¹.
• Where a code is used, show it at the entrance and in a standard-format QR code, and expect to restart the broadcast to change it^2,7,6.
• Avoid short, guessable codes⁴.
• Plan how people without a smartphone will join a protected stream, for example with loan receivers^3,8.

Sources

1. How to build an Auracast transmitter: technical overview, version 3. Bluetooth SIG Market Development. Bluetooth SIG, 16 September 2026. Standards body (Bluetooth SIG, an industry association funded by its member companies, which owns the Auracast trademark) ↩︎ https://www.bluetooth.com/wp-content/uploads/2024/05/2403_How_To_Auracast_Transmitter.pdf
2. A new Bluetooth audio scan-to-listen experience. Bluetooth SIG Market Development. Bluetooth SIG, 17 February 2025. Trade body (Bluetooth SIG marketing material; the SIG is an industry association funded by its member companies and owns the Auracast trademark) ↩︎ https://www.bluetooth.com/wp-content/uploads/2025/03/02.20.25_Auracast_QR_Paper_FINAL.pdf
3. Auracast: a revolution in audio accessibility (RNID Auracast report). RNID (Royal National Institute for Deaf People). RNID, 11 February 2025. Nonprofit advocacy (RNID, UK charity) ↩︎ https://rnid.org.uk/wp-content/uploads/2025/02/Final-Auracast-Report-110225.pdf
4. Can Bluetooth Auracast be used as an assistive listening system?. Pro Audito Schweiz. Pro Audito Schweiz (in German), 17 February 2025. Nonprofit advocacy (Pro Audito Schweiz, Swiss hearing-loss association) ↩︎ https://pro-audito.ch/news/kann-bluetooth-auracast-als-hoeranlage-eingesetzt-werden/
5. Public Broadcast Profile, version 1.0.2. Bluetooth SIG Audio, Telephony, and Automotive Working Group. Bluetooth SIG, 3 November 2025. Standards body (Bluetooth SIG, an industry association funded by its member companies, which owns the Auracast trademark) ↩︎ https://www.bluetooth.com/wp-content/uploads/Files/Specification/HTML/pbp_v1-0-2_1761252922/PBP_v1.0.2/out/en/index-en.html
6. How to build an Auracast assistant: technical overview, version 1.0. Bluetooth SIG Market Development. Bluetooth SIG, 29 October 2025. Standards body (Bluetooth SIG, an industry association funded by its member companies, which owns the Auracast trademark) ↩︎ https://www.bluetooth.com/wp-content/uploads/2024/05/2403_How_To_Auracast_Assistant.pdf
7. Broadcast Audio URI, version 1.0. Bluetooth SIG Hearing Aid Working Group. Bluetooth SIG, 10 September 2024. Standards body (Bluetooth SIG, an industry association funded by its member companies, which owns the Auracast trademark) ↩︎ https://www.bluetooth.com/wp-content/uploads/Files/Specification/HTML/BAU_v1.0/out/en/index-en.html
8. Tested for you: the Avantree Venucast Oasis Aura Auracast transmitter (in German). Pro Audito Schweiz, 16 July 2026. Independent (Pro Audito Schweiz, Swiss hearing-loss association; test units supplied free by the manufacturer, Pro Audito not paid) ↩︎ https://pro-audito.ch/news/fuer-sie-getestet-auracast-sender-avantree-venucast-oasis-aura/
9. Bluetooth Auracast in theaters and event venues. Graf B (Pro Audito Schweiz). Proscenium no. 3, pp. 10-11, Swiss Association of Technical Stage and Event Industry; English reprint by the Center for Hearing Access, September 2026. Nonprofit advocacy (Pro Audito Schweiz, Swiss hearing-loss association) ↩︎ https://centerforhearingaccess.org/wp-content/uploads/Proscenium-Technical-article-Bluetooth-Auracast-in-theaters-and-event-venues-1.pdf
10. Auracast transmitter-receiver compatibility test (with data workbook). Pro Audito Schweiz, 6 October 2025. Independent (Pro Audito Schweiz, Swiss hearing-loss association; no manufacturer funding, test products lent free by manufacturers) ↩︎ https://pro-audito.ch/news/auracast-transmitter-receiver-compatibility-test/
11. BACON: improving broadcast audio authentication. Gasteiger T, Perazzo P, Schuß M, Boano CA, Basic F, Dini G, Römer K. IEEE MILCOM 2024 (Graz University of Technology; University of Pisa), 28 October 2024. Independent (Graz University of Technology; University of Pisa); funding not stated in the paper ↩︎ https://doi.org/10.1109/MILCOM61039.2024.10774045
12. 28 CFR 36.303: auxiliary aids and services (ADA Title III regulation). US Department of Justice. eCFR, 18 January 2017. Government (US Department of Justice) ↩︎ https://www.ecfr.gov/current/title-28/section-36.303
13. 2024 International Building Code, Chapter 11 Accessibility: 1109.2.7 Assistive listening systems and 1112.4 Other signs. International Code Council. International Code Council (ICC Digital Codes), August 2023. Standards body (International Code Council) ↩︎ https://codes.iccsafe.org/content/IBC2024P1/chapter-11-accessibility
14. prSIA 500:2025-07 Hindernisfreie Bauten (obstacle-free buildings), consultation draft. SIA (Swiss Society of Engineers and Architects). SIA; consultation copy with highlights published by Pro Audito Schweiz (in German), July 2025. Standards body (SIA) ↩︎ https://pro-audito.ch/wp-content/uploads/prSIA500_Vernehmlassungsentwurf-mit-Hervorhebungen.pdf
15. Höranlagen heute und morgen. Was ändert sich mit der neuen Technologie Auracast? (Hearing systems today and tomorrow: what changes with Auracast?). Hindernisfreie Architektur, the Swiss national centre for barrier-free architecture, with recommendations from Pro Audito Schweiz. hindernisfreie-architektur.ch (in German), 19 May 2025. Nonprofit advocacy (donation-funded Swiss specialist centre) ↩︎ https://hindernisfreie-architektur.ch/fachinformation/hoeranlagen-heute-und-morgen-was-aendert-sich-mit-der-neuen-technologie-auracast/

Change log

• 10 October 2026Published with 15 sources.
• 13 October 2026Corrected the code-entry summary, qualified the Swiss draft and clarified the limits of shared-code authentication.
• 13 October 2026Independent audit restricted wireless code transfer to the tested clip receivers.
• 13 October 2026Aligned the equipment context with the source: supplied free by the manufacturer, with loan status unstated.

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