Physical Attributes — YubiKey Technical Manual documentation (2024)

The serial number is printed on the back of every YubiKey in the YubiKey 5 Series, YubiKey 5 FIPS Series, YubiKey 5 CSPN Series, and YubiKey Bio Series. The 2D barcode (Data Matrix code) of the serial number is also printed on the back of every YubiKey in the 5 Series (as well as on the FIPS and CSPN) except on the5C Nano form factor, which is too small to accommodate the 2D barcode.

In addition, all of the keys in the YubiKey 5 FIPS Series have the acronym “FIPS” underneath the Data Matrix code on the back, along with “v5” running up the left side of the Data Matrix code, except on the YubiKey 5C Nano, which has it on the right.

All current YubiKeys have been IP68-rated under the IEC standard 60529.

YubiKey 5 NFC

Important

The attributes listed below also apply to the YubiKey 5 NFC FIPS, YubiKey 5 NFC CSPN, Security Key NFC, and the Security Key NFC - Enterprise Edition.

Dimensions: 18mm x 45mm x 3.3mm
Weight: 3.7g
Physical Interfaces: USB, NFC
Operating Temperatures: 0 °C - 40 °C (32 °F - 104 °F)
Storage Temperatures: -20 °C - 85 °C (-4 °F - 185 °F)

For more information, see our Support article on the YubiKey 5 NFC.

YubiKey 5 Nano

Important

The attributes listed below also apply to the YubiKey 5 Nano FIPS, and the YubiKey 5 Nano CSPN.

Dimensions: 12mm x 13mm x 3.1mm
Weight: 0.5g
Physical Interfaces: USB
Operating Temperatures: 0 °C - 40 °C (32 °F - 104 °F)
Storage Temperatures: -20 °C - 85 °C (-4 °F - 185 °F)

For more information, see our Support article on the YubiKey 5 Nano.

YubiKey 5C

Important

The attributes listed below also apply to the YubiKey 5C FIPS and the YubiKey 5C CSPN.

YubiKey 5C Nano

Important

The attributes listed below also apply to the YubiKey 5C Nano FIPS and the YubiKey 5C CSPN.

Dimensions: 12mm x 10.1mm x 7mm
Weight: 0.7g
Physical Interfaces: USB
Operating Temperatures: 0 °C - 40 °C (32 °F - 104 °F)
Storage Temperatures: -20 °C - 85 °C (-4 °F - 185 °F)

For more information, see our Support article on the YubiKey 5C Nano.

YubiKey 5Ci

Important

The attributes listed below also apply to the YubiKey 5Ci FIPS and the YubiKey 5Ci CSPN.

Dimensions: 12mm x 40.3mm x 5mm
Weight: 2.8g
Physical Interfaces: USB, Lightning®
Operating Temperatures: 0 °C - 40 °C (32 °F - 104 °F)
Storage Temperatures: -20 °C - 85 °C (-4 °F - 185 °F)

For more information, see our Support article on the YubiKey 5Ci.

YubiKey 5C NFC

Important

The attributes listed below also apply to the YubiKey 5C FIPS, YubiKey 5C NFC CSPN, Security Key C NFC, and the Security Key C NFC - Enterprise Edition.

Dimensions: 18mm x 45mm x 3.7mm
Weight: 4.3g
Physical Interfaces: USB, NFC
Operating Temperatures: 0 °C - 40 °C (32 °F - 104 °F)
Storage Temperatures: -20 °C - 85 °C (-4 °F - 185 °F)

For more information, see our Support article on the YubiKey 5C NFC.

YubiKey Bio Series

The YubiKey Bio - FIDO Edition is available in the USB-A format, while the YubiKey C Bio - FIDO Edition is available in the USB-C format, both have a maximum transfer rate of 12 Mbps.

The sensors and LEDs behave the same way in both formats.

YubiKey Bio - FIDO Edition

For more information, see our Support article on the YubiKey Bio - FIDO Edition.

YubiKey C Bio - FIDO Edition

For more information, see our Support article on the YubiKey C Bio - FIDO Edition.

Laser Marking

The laser marking of the FIDO Edition of the YubiKey Bio Series was changed in March 2024. To distinguish the FIDO Edition from the Multi-protocol Edition, ‘FIDO’ is marked on the back near the serial number and data matrix. YubiKeys of product type YubiKey Bio Series - FIDO Edition produced before March 2024 do not have ‘FIDO’ marked on the back, instead they have only the serial number and data matrix on the back.

YubiKey Bio Series - FIDO Edition marked ‘FIDO’, March 2024 and later

YubiKey Bio Series - Multi-protocol Edition and YubiKey Bio Series - FIDO Edition prior to March 2024

Sensors

The YubiKey Bio recognizes two interactions, one a touch, and the other a fingerprint. Its recognition of the fingerprint - or lack thereof - is communicated through the LEDs. See LED Behavior.

On the YubiKey Bio, the silver-colored bezel encircling the fingerprint sensor provides the grounding plane required to read the fingerprint. Touch types:

Biometric:	When prompted to have the YubiKey Bio read your fingerprint from the fingerprint sensor, be sure to touch at least a tiny part of the ring. If you use your little finger to touch only the center of the fingerprint sensor, the key does not read the fingerprint.
Plain:	When prompted to touch the YubiKey Bio but not explicitly asked for the fingerprint, touch both the bezel and the fingerprint sensor, even though the fingerprint is not read.

Fingerprint Tips provides detailed instructions on using the fingerprint sensor.

LEDs

The YubiKey Bio has a green LED and an amber LED to provide direct feedback. It flashes when the key is ready for interaction or is communicating something about the interaction. LED Behavior provides detailed descriptions.

Ratings

The YubiKey Bio has been IP68-rated under the IEC standard 60529.

Care and Cleaning

To clean the YubiKey and sensor, use only wipes impregnated with no more than 70% isopropyl alcohol.

Operational Data

Dimensions
- YubiKey A Bio: 18mm x 45mm x 3.35mm
- YubiKey C Bio: 18mm x 45mm x 3.75mm
Weight: YubiKey Bio A: 4.3g; YubiKey Bio C: 5.0g
Operating Temperatures: 0 °C - 40 °C (32 °F - 104 °F)
Storage Temperatures: -20 °C - 85 °C (-4 °F - 185 °F)

FIPS-specific Marking

CSPN-specific Marking

Security Key Series Marking

The color of the non-Enterprise edition of the Security Key Series was changed to black in January 2023. To distinguish the keys in the Security Key Series from those in the YubiKey 5 Series, FIDO is inscribed on the backs of both the Enterprise Edition and otherwise.

The serial number is inscribed on the back of each key in the Enterprise edition of the Security Key Series.

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