Dongle

A dongle is a small hardware device that connects to a computer or other device, most commonly via USB but also through Bluetooth, NFC, or other interfaces. It serves to provide a separate function beyond the host device’s built-in capabilities, or to act as a form of licensing or authentication for software.

In software licensing, dongles function as hardware keys. The software checks for the presence of the dongle and only runs when the key is detected. Dongles may store cryptographic data, serial numbers, or certificates and can require drivers or specialized runtime environments. They are widely used to deter counterfeiting and to manage licenses, especially in professional or enterprise settings.

Types include USB security dongles and other peripheral keys, as well as wireless or network dongles. USB security dongles are often used by software vendors to enforce licensing and may support multiple platforms. Additional examples include USB Wi‑Fi adapters, Bluetooth dongles, and HDMI or streaming dongles that enable display or media functions. Some devices rely on smartcard or NFC-based dongles for authentication.

Advantages and challenges: dongles can enable offline licensing and portable validation, simplify license management in organizations, and provide strong hardware-based security. Drawbacks include the risk of loss or damage, higher upfront costs, driver or compatibility issues, and potential inconvenience for users who must carry or connect the device. As a trend, many vendors are moving toward online activation or cloud-based licensing to reduce reliance on physical keys.

The term originated in the 1980s to describe hardware lock devices used to prevent software piracy; the etymology is unclear. See also hardware security module, USB dongle, and software licensing.