The industry association that maintains the Qi specification for wireless
charging, the Wireless Power Consortium or WPC, doesn’t issue major updates
very often, but when they do, it’s usually something major, like a big
increase in power output, a large step up in efficiency or a significant new
Take the last revision, for example. Released more than seven years ago, in
2015, Qi v1.2 extended charging beyond 5 watts, adding the ability to send up
to 15 watts of power during a charge. It was the first substantial update to
the specification since its introduction in 2010, and it suddenly made Qi a
viable option for a much wider range of electronic devices.
Now, in 2022, it’s a similar story. Qi v1.3, which was recently made available
for download from the WPC website, adds secure authentication between the
transmitter (the charger) and the receiver (the device to be charged). It’s an
important change, since it increases safety and creates a better charging
experience, and because it changes how Qi devices are designed and certified.
Qi v1.3 Authentication
Qi v1.3’s authentication is, in some ways, a logical extension of Qi v1.2,
because Qi v1.3 adds an extra layer of protection when choosing the power
level. Qi v1.3 defines two major power profiles: the Baseline Power Profile,
which delivers up to 5 watts of output, and the Extended Power Profile, which
delivers a maximum of 15 watts for what is called “fast charging”.
To safeguard devices and their users, the Extended Power Profile requires the
use of hardware-based authentication. Before charging takes place, the
receiver (the device to be charged) first confirms that it is interacting with
a Qi-certified transmitter (the charging pad). Then, having authenticated the
transmitter, the receiver requests the most appropriate and safest level of
charging. If authentication fails, then the receiver can either cancel the
request entirely or limit the amount of power it will accept.
Qi v1.3 authentication ensures that the transmitter and the receiver will work
together as intended, with the expected level of charging output, so battery
refills go smoothly. Authentication also helps avoid the risks of using
non-certified chargers, which can permanently damage electronic components,
make the device being charged too hot to touch, or, worse yet, start a fire.
Qi v1.3 Authentication
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What Qi v1.3 Means for Certification
The WPC’s Qi certification process already has strong industry support and is
widely recognized for its commitment to safety. Even before the introduction
of Qi v1.3, the certification process included a number of safety checks, so
manufacturers who passed Qi certification could be confident that their
devices implemented Qi’s various safety features correctly and consumers
could be certain they were buying a quality build.
The introduction of Qi v1.3 changes the certification process, with additional
steps to verify the new authentication algorithm. To pass Qi v1.3
certification, the Extended Power Profile must use a tamper-resistant
subsystem that protects the private key and certificate used for
authentication. More specifically, each wireless charger unit must contain a
unique private key and a unique certificate, called the product unit certificate.
The product unit certificate must be issued by a provider who complies with
the security requirements specified by the WPC, known as an Approved
Manufacturer Certificate Authority Service Provider. Designing and
implementing the necessary tamper-resistant subsystem, and then establishing a
secure process for issuing and injecting product unit certificates, is a
complex, time-consuming task, involving specialized techniques that are often
unfamiliar to hardware and software developers.
This is where NXP comes in. We are an Approved Manufacturer CA Service
Provider, and we offer a turnkey solution for Qi v1.3 certification, so it’s
easy to deliver Qi-compliant devices that offer safe, satisfying charging
Turnkey Solution for Qi 1.3 Certification
The diagram gives an overview of how the process works.
NXP is an Approved Manufacturing CA Service Provider
We issue a product unit certificate for each wireless charger. The certificate
is signed by a manufacturer certificate authority, created specifically for
the device manufacturer and itself signed by the WPC root certificate authority. The product unit certificate and its corresponding private key can
be secured by the
NXP EdgeLock SE05x
secure element or the NXP EdgeLock A5000 secure authenticator, two
WPC-compliant ICs. The EdgeLock SE05x and the EdgeLock A5000 store and protect
the Qi private product unit key and certificate and support ECC NIST-256 for
implementing Qi Authentication messages.
NXP’s WPC-compliant ICs protection authentication
The EdgeLock A5000 is tailored for basic wireless charging, while the EdgeLock
SE05x supports additional use cases, for devices that, in addition to wireless
charging, also support features like secure connection to the cloud or
interoperability with the new IP-based Matter specification for connectivity.
Purpose-Built Hardware, Software and Services
The hardware configuration includes an IoT applet for ECDSA and other
cryptographic operations and is available with middleware that facilitates
communication with the host. The EdgeLock SE05x and EdgeLock A5000 use the I2C
protocol, so they can be attached to just about any microcontroller or
microprocessor and are tailored for device authentication, so they deliver
optimal performance while minimizing the amount of computing resources
required on the host.
Example source code and documentation, supplied with the EdgeLock SE05x and
EdgeLock A5000, gives developers a head start on charger design and makes it easier to pass
certification. Also, as part of NXP’s EdgeLock 2GO service, we can provision
the EdgeLock SE05x or EdgeLock A5000 with the private product unit keys and
certificates required for Qi authentication. There’s no need to establish a
costly and complex PKI infrastructure, and charger production can take place
in third-party facilities without adding security risk.
EdgeLock SE05x secure element and EdgeLock A5000 secure authenticator
Having a stable, carefully maintained specification, backed by a solid program
for certification, has helped Qi become the de facto standard for wireless
charging. The Qi format is already used by millions and millions of people
around the world every day, as a convenient way to top up the batteries in
their smartphones, mobile accessories and small appliances.
Now, with the power profiles and secure authentication defined in Qi v1.3, the
charging experience can be safer and more enjoyable than ever before. The new
mandate for hardware-based authentication is, admittedly, a significant change
in terms of design, test and certification, but with turnkey solutions like
ours, manufacturers can move quickly to meet the new requirements.
Take the Next Step
To learn more about our security and authentication solutions for Qi charging
and other IoT applications, visit