Also supported is the PKCS#11 standard to emulate a PIV smart card. A YubiKey can also present itself as an OpenPGP card using 1024, 2048, 30-bit RSA (for key sizes over 2048 bits, GnuPG version 2.0 or higher is required) and elliptic curve cryptography (ECC) p256, p384 and more depending on version, allowing users to sign, encrypt and decrypt messages without exposing the private keys to the outside world. The YubiKey implements the HMAC-based One-time Password Algorithm (HOTP) and the Time-based One-time Password Algorithm (TOTP), and identifies itself as a keyboard that delivers the one-time password over the USB HID protocol.

Yubico also manufactures the Security Key, a similar lower cost device with only FIDO2/WebAuthn and FIDO/U2F support. Google, Amazon, Microsoft, Twitter, and Facebook use YubiKey devices to secure employee accounts as well as end user accounts. YubiKey also allows for storing static passwords for use at sites that do not support one-time passwords. It allows users to securely log into their accounts by emitting one-time passwords or using a FIDO-based public/private key pair generated by the device. The YubiKey is a hardware authentication device manufactured by Yubico to protect access to computers, networks, and online services that supports one-time passwords (OTP), public-key cryptography, and authentication, and the Universal 2nd Factor (U2F) and FIDO2 protocols developed by the FIDO Alliance.

First YubiKey USB token of the FIDO standard in 2014.

Yubico security key