BSI standards, certification and the smart metering PKI

Six parts, ten years apart

15 December 2014 and 13 December 2024. Both dates appear in the same document, the umbrella document of the BSI technical guideline TR-03109, version 2.0.1 of 8 December 2025. The older one belongs to the security module, the newer one to the gateway¹.

TR-03109 is a family of six parts, each covering one component or role, each with its own version¹:

Part 3 is younger than it looks. It refers to TR-03116-3, which the umbrella document says is updated every year¹. The edition in force is still "Stand 2025" from December 2024⁴; no 2026 edition had appeared by mid-October 2026⁵. Part 4, the PKI, has no such shortcut. Its text is from 2017.

Why should a list of versions matter? Because the law is tied to it. Under section 22(2) of the Metering Point Operation Act (MsbG), a gateway is presumed to meet the state of the art if it complies with the BSI's protection profiles and guidelines in the version currently in force. Which version that is, the Federal Gazette announces by pointing to the BSI's website⁶.

So, legally, what counts in the end is a web page. Keep that in mind. It explains a false alarm this chapter comes back to.

One gateway, two certificates

For the gateway, the protection profile is BSI-CC-PP-0073. Version 2.0 is dated 13 December 2024, and its certificate, issued on 19 December 2024, runs until 18 December 2034. It is evaluated at EAL 4, augmented by AVA_VAN.5 and ALC_FLR.2⁷.

Behind the acronyms lies a trade-off the profile states openly. AVA_VAN.5 demands resistance against attackers with high attack potential. EAL 4 was picked "to keep evaluations according to this PP commercially feasible", the profile says, because it is the lowest level at which AVA_VAN.5 is possible at all⁸. The toughest penetration testing, middling depth everywhere else. A compromise, and an honestly argued one.

Most of the weight lies on the wide area network, and the threat model says why. Someone who has to get physically at a device compromises one at a time. An attack from the WAN may hit a great many⁸.

Two things the profile deliberately leaves out. Availability isn't a security objective, since under section 25 MsbG reliable operation is the gateway administrator's job⁹. And the security module that holds the keys is a separate product with its own protection profile, even though it sits inside the gateway⁷. Version 2.0 also brings two functional packages: "Power Limitation" for gateways that control devices themselves, and "Multiple grid connection points" for gateways that bundle meters of several grid connections at the same grid node⁷. For control, the BSI followed up with a non-binding implementation note on 16 September 2025¹⁰. Chapters 4 and 5 deal with what that means.

The protection profile is only half the story, though. TR-03109-1 adds functional requirements and has a procedure of its own, with test specification 2.0 of 10 June 2025 as the basis for testing¹. Section 24 MsbG demands both: security certification by the BSI under the Common Criteria or the European EUCC scheme, and conformity certificates for the guidelines¹¹. EUCC has applied since 27 February 2025¹². Procedures under the national scheme had to be completed by 27 February 2026¹³, and new security certificates for gateways have carried an EUCC number since then¹⁴. Metrology law adds a third check: for the functions relevant to legal metrology, the PTB issues a type-examination certificate¹⁵.

Here is what that looks like in the BSI product list. EFR's Secure Smart Grid Hub, version 2.00, has an EUCC certificate of 20 March 2026 and a TR certificate of 24 March 2026, listed separately¹⁴. Both still belong to the old state: the EUCC certificate names version 1.3 of the protection profile¹⁶, the TR certificate names TR-03109-1 version 1.1 as its test basis¹⁷. The same holds for all five gateways on the list. As of mid-October 2026 the BSI lists no certificate against protection profile 2.0 or guideline 2.0. Without a valid certificate shown to the administrator, a gateway may not form part of an intelligent metering system¹¹.

What about older devices? Initial certification against protection profile 1.3 and guideline 1.1 is over. Applications for recertification on the old basis are possible until 31 December 2027 at the latest, and for the protection profile since 27 February 2025 only with a security target moved to CC:2022. Such gateways may be installed until then. Devices already in the field can migrate to the new state through a software update. From 1 January 2027, certifications against version 2.0 must also prove the MUSS+ requirements, which the BSI sums up as "u.a. WAN-API, RLM über LMN & Werksreset durch SRV": among others a WAN API, load profile metering over the local metrological network and a factory reset by the service technician¹².

The gateway administrator: two proofs, no single deadline

Once a year the auditor turns up and picks a sample. Within three years, every requirement of TR-03109-6 has to have been checked at least once¹⁹.

That is the audit rhythm for the gateway administrator, the party that commissions gateways and manages them remotely. Section 25 MsbG requires it to run an information security management system and to have a security concept, both audited regularly by auditors the BSI has certified for the purpose. Proof comes from a certificate issued by the BSI or by a body accredited under ISO/IEC 27006, and the audit report goes to the BSI⁹.

That reads like one proof. It's two.

TR-03109-6 draws a clean line. An administrator's management system under ISO/IEC 27001 or IT-Grundschutz is examined in its own ISMS certification, while the TR-03109-6 audit checks nothing but the guideline's own minimum requirements¹⁹.

Version 2.0 is dated 28 November 2025. Consent from the economics ministry followed on 9 December 2025, and on 17 December the BSI announced publication²⁰. New items include rules for remote workplaces and cloud providers, a zero trust concept and the operation of the administrator's time servers. Those requirements used to sit in PTB requirements 50.8 and a PTB information sheet; now they are part of a BSI guideline¹⁹. Legal time still comes from the time servers of the PTB, the national metrology institute.

Version 2.0 applies from 1 January 2027 with the next initial certification or recertification of the administrator's system, and may be used voluntarily before that¹⁹. Version 1.0 stays valid until the end of 31 December 2028¹.

So there's no single cut-off date. Each administrator has its own, set by its own certification calendar. One that recertifies under version 1.0 in 2026 can work with that until the end of 2028 at most. If the next date falls in 2027, the audit is against version 2.0 straight away. Until the end of 2028, certificates under both versions coexist in the market.

The smart metering PKI: one anchor, many branches

How does a gateway know it is talking to the right administrator? Through a certificate whose chain ends at a single root.

Under section 28 MsbG, the BSI itself holds the root certificates²². The Root CA has been in live operation since 1 March 2015, run by a certification service provider under BSI supervision. The BSI's page doesn't say who²³. Below it sit eleven registered Sub-CAs, run by IT service providers, manufacturers, gateway administration service providers and grid operators²⁴. They issue the certificates of the end users: external market participants, gateway administrators, gateway manufacturers and the gateways themselves²⁵.

Each end user gets three certificates with separate keys, one for TLS, one for encryption, one for signatures. There's a reason for that. Readings can travel through the administrator rather than straight to their recipient, so the connection is secured with TLS and the content is also encrypted and signed for the final recipient²⁵. The administrator then carries data it can't read.

At the factory, the security module already receives so-called seal certificates. With these the gateway proves it is genuine when it is commissioned, after which operational certificates take over. The gateway checks a certificate chain against the trust anchor in its security module, but without a revocation list. Revocation status is the administrator's job²⁵. A detail with consequences: the revocation list lives in the back end.

Connections initiated from outside in the WAN aren't accepted at all. When the administrator needs it right away, it sends a wake-up, a signed message after which the gateway opens the connection itself, either to the administrator or to an external market participant together with a device in the home network. Replayed messages must be detected⁸.

Renewal as a permanent state

The certificates expire, and quickly. The root certificate is valid for eight years, but its key may only sign for three. Sub-CA certificates run for five years, the administrator's for three, those of the gateway and all other end users for two²⁵. The certification authorities change their own certificates even sooner: under the certificate policy, the Root CA every three years and each Sub-CA every two²⁶.

What does that mean across the country? By 30 June 2026, intelligent metering systems were installed at 3,172,579 metering locations²⁷. If each had its own gateway, three new certificates per device would be due every two years, some 4.8 million a year before a single new installation. That's our own estimate and an upper bound, since one gateway can serve several meters⁷. How many gateways there actually are, the statistics don't say.

Then there's the change at the root. After three years at most, the Root CA needs a new key pair and publishes a link certificate signed with the old key. Only once that has been checked against the old anchor may the new root certificate act as anchor, and when the old one expires the new one replaces it entirely²⁵. With every new certificate the administrator sends the gateway the whole chain down to the anchor it has stored, link certificates included²⁵.

Post-quantum: the threat is in the text, the method isn't yet

On 11 February 2026 the BSI recommended an end date for classical asymmetric encryption for the first time. By the end of 2030, such methods should no longer be used on their own for the most sensitive applications, by the end of 2031 not on their own for any application, and for signatures the end of 2035 is planned. The way forward is hybrid: classical methods stay, post-quantum ones are added on top²⁸.

On 12 October 2026 the interior ministry, the digital ministry and the BSI followed up. Their joint guideline implementing the EU roadmap is addressed expressly to operators of critical infrastructure as well. Preparation should be complete by the end of 2026, high-risk use cases should be quantum-safe by the end of 2030 and medium-risk ones by the end of 2035. Besides "store now, decrypt later", the guideline names the long migration times of devices with a long service life as a reason²⁹.

Little of this has reached smart metering. TR-03116-3, "Stand 2025", forecasts the security of its methods six years ahead to 2030 and marks them "2030+". It prescribes elliptic-curve schemes such as ECDSA and names no post-quantum method at all⁴.

Yet the threat itself is already written into a guideline. Version 2.0 of TR-03109-6 lists the cryptographically relevant quantum computer as threat B.GWASYS.13. Because public key infrastructures, hardware crypto modules and non-updatable firmware on constrained devices take so long to migrate, it says, the threat must be met "unmittelbar und nicht erst bei Verfügbarkeit von CRQC", immediately and not only once such a machine exists¹⁹.

It would be hard to put the problem more precisely. Nor does the guideline stop at the sentence: the administrator must record the cryptographic methods and key lengths of its system in a crypto inventory, should derive a prioritised migration concept from it and must carry out its measures¹⁹. Only all of this applies to the administrator. The protection profile for the device doesn't contain the word "quantum" once⁸, the guideline for the security module is from 2014¹, and that's exactly where the keys live.

Counterpoint: where does a communication adapter end?

To control a heat pump under §14a EnWG, a device in the home network terminates the gateway's secured channel. Since 2024 that device falls under TR-03109-5, and industry and the BSI argued over its scope before it took effect³.

On 13 October 2023 the association of the new energy industry, bne, wrote that the draft made the connection far more complicated than necessary. Because the housing defined the boundary, a heat pump, charger or storage unit with an integrated adapter would fall under the guideline as a whole. Practically all such devices have a cloud connection and would therefore need the accelerated security certification, the BSZ, at market launch and with every software update. It wanted testing limited to the adapter and recertification only for updates that touch it³⁰.

The BSI held its line in the final version of 24 November 2023. The boundary is "die gesamte Hardware, die in ihrem Gehäuse integriert ist", all the hardware inside the housing, and the whole physical component is tested. Security certification, however, is only mandatory where the assessment under section 2.9 calls for it. For the agile rollout, a manufacturer's self-declaration sufficed during 2024³. Its FAQ goes further: the object of evaluation is always a stand-alone physical product, software-only certification doesn't exist, and changed versions usually need recertification³¹.

The reason is in the protection profile. An attacker might first take over a device in the home network and then attack the gateway from there⁸. An adapter inside a connected heat pump is exactly that kind of device.

So what happened? By mid-October 2026 the BSI lists 26 certificates under TR-03109-5. The products are called control box, control module, CLS adapter or smart reader. Not one is a heat pump, a wallbox or a storage unit³².

That fits the bne's warning without proving it. Device makers may have other reasons to leave the connection to a separate box.

The BSI draws the line where an attacker gets into the home network. The bne draws it where a manufacturer can still certify at a reasonable cost. Both lines have reasons behind them. They just don't coincide. A year later the BDEW and the BSI clashed in a similar way over control directly in the gateway, as chapter 4 describes³³.

The certification cycle as a planning factor

A new gateway function takes three steps. First comes a new version of the guideline: the BSI drafts it on behalf of the economics ministry, in agreement with the PTB and the Federal Network Agency. For major changes the Gateway Standardisation Committee, where associations of consumers, manufacturers and users sit too, is then heard under the ministry's chair, and publication follows only once the ministry consents³⁴. Then every manufacturer has its device tested, twice. Last, the administrator pushes the update into the field, and only firmware the BSI has released¹⁹.

The product list shows how tight the cycle runs. For a single gateway model, Theben's CONEXA 3.0, it shows TR certificates dated 31 January 2022, 31 May 2023, 16 February 2024, 5 May 2025 and 14 October 2025¹⁴. Five conformity checks in not quite four years.

Further development used to follow the BSI's staged model of energy-sector use cases, system use cases and function blocks, last in version 2.1 of November 2021³⁷. No newer version has been published, and development now visibly runs through the guidelines themselves. Chapter 4 places the tariff use cases in those stages.

Four checks for grid and metering point operators:

1. Find the date of your own administrator certification

   If the next initial certification or recertification of your administrator system falls in 2027 or later, the audit is against version 2.0 of TR-03109-6. Start the gap analysis on remote workplaces, service providers and time servers before the audit date. If you buy in gateway administration, ask your provider for its date.

2. Ask about the certification status of each gateway model

   Against which versions of the protection profile and TR-03109-1 is the model certified, and can an update bring it up to the new state? The BSI table doesn't show this, but the page for each certificate does: it names the protection profile with its version and the test basis of the TR certification^16,17.

3. Use the installation window up to the end of 2027 deliberately

   Gateways on the old state may only be installed until 31 December 2027. As of mid-October 2026, no gateway on the new state is certified^16,17. Ask your manufacturers when they expect certification under version 2.0, and plan procurement and rollout for 2027 and 2028 around those dates.

4. Check certificate renewal as an operational process

   Ask your Sub-CA and your gateway administrator to show you how expiring certificates are monitored, revocation lists are checked and the next Root CA changeover is prepared. Two-year lifetimes across millions of metering points leave no room for manual work.