Note: This article lists the technical specifications of the YubiKey 5C. If you're looking for setup instructions for your YubiKey 5C, see https://www.yubico.com/start.

The YubiKey 5C has six distinct applications, which are all independent of each other and can be used simultaneously. Note: Some software such as GPG can lock the CCID USB interface, preventing another software from accessing applications that use that mode.

Interface

The YubiKey 5C uses a USB 2.0 interface. All of the applications are available through this interface.

Applications

FIDO2

The FIDO2 application allows for secure single and multi-factor authentication, and can store up to 25 resident credentials. These credentials, which are protected by a PIN, enable passwordless login, where the YubiKey, unlocked by a PIN and authorized by touch, can log you in to your accounts without entering a username or password. The FIDO2 application is FIDO certified.

USB Interface: FIDO

More about FIDO 2

OTP

The OTP applet contains two programmable slots, each can hold one of the following credentials:

• Yubico OTP
• HMAC-SHA1 Challenge-Response
• Static Password
• OATH-HOTP

USB Interface: OTP

U2F

The U2F application can hold an unlimited number of U2F credentials and is FIDO certified.

USB Interface: FIDO

OATH

The YubiKey 5 series can hold up to 32 OATH credentials and supports both OATH-TOTP (time based) and OATH-HOTP (counter based). Accessing this applet requires Yubico Authenticator.

USB Interface: CCID

PIV (Smart Card)

This application provides a PIV compatible smart card. On Windows, the smart card functionality can be enhanced with the YubiKey Smart Card Minidriver.

Default Values:

• PIN: 123456
• PUK: 12345678
• Management Key: 010203040506070801020304050607080102030405060708

Supported Algorithms:

• RSA 1024
• RSA 2048
• ECC P256
• ECC P384

Slot Information:

• Slot 9a: Authentication
• Slot 9b: Management Key
• Slot 9c: Digital Signature
• Slot 9d: Key Management
• Slot 9e: Card Authentication
• Slot f9: Attestation
• Slots 82-95: Retired Key Management

USB Interface: CCID

More info about PIV

OpenPGP

This application implements version 2.0 of the OpenPGP Smart Card specification which can be used with GnuPG. In YubiKey firmware versions 5.2.3 and later, version 3.4 of the OpenPGP Smart Card spec is implemented instead (refer to this article for more details). For key sizes over 2048 bits, GnuPG version 2.0 or higher is required.  

Supported Algorithms:

• RSA 1024
• RSA 2048
• RSA 3072
• RSA 4096

Additional Supported Algorithms (firmware 5.2.3 and higher):

• secp256r1
• secp256k1
• secp384r1
• secp521r1
• brainpoolP256r1
• brainpoolP384r1
• brainpoolP512r1
• curve25519
  • x25519 (decipher only)
  • ed25519 (sign / auth only)

USB Interface: CCID

Physical Specifications

Form Factor

Connector: USB-C
Dimensions: 12.2mm x 29.1mm x 4.8mm
Weight: 2g

Temperatures

Operational range: 0 °C to 40 °C (32 °F to 104 °F)
Storage range: -20 °C to 85 °C (-4 °F to 185 °F)