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(DEPRECATED) Java server-side library for U2F

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== java-u2flib-server

DEPRECATED: U2F has been superseded by[Web Authentication], and this project is superseded by[java-webauthn-server]. We recommend using WebAuthn instead for new deployments. This project will only receive bug fixes, and will not be developed further.

image:["Build Status", link=""] image:["Coverage Status", link=""]

Server-side[U2F] library for Java. Provides functionality for registering U2F devices and authenticating with said devices.

=== Dependency

Maven: [source, xml] com.yubico u2flib-server-core 0.19.9

Gradle: [source, groovy] repositories{ mavenCentral() } dependencies { compile 'com.yubico:u2flib-server-core:0.19.9' }

=== Example Usage NOTE: Make sure that you have read[Using a U2F library] before continuing.

[source, java]

private abstract Iterable getRegistrations(String username);

@GET public View startAuthentication(String username) throws NoEligibleDevicesException {

// Generate a challenge for each U2F device that this user has registered
SignRequestData requestData
    = u2f.startSignature(SERVER_ADDRESS, getRegistrations(username));

// Store the challenges for future reference requestStorage.put(requestData.getRequestId(), requestData.toJson());

// Return an HTML page containing the challenges return new AuthenticationView(requestData.toJson(), username);


@POST public String finishAuthentication(SignResponse response, String username) throws DeviceCompromisedException {

// Get the challenges that we stored when starting the authentication
SignRequestData signRequest
    = requestStorage.remove(response.getRequestId());

// Verify the that the given response is valid for one of the registered devices u2f.finishSignature(signRequest, response, getRegistrations(username));

return "Successfully authenticated!";


In the above example

will return the U2F devices currently associated with a given user. This is most likely stored in a database. See link:u2flib-server-demo[
] for a complete demo server (including registration and storage of U2F devices).

=== JavaDoc JavaDoc can be found at[].

=== Attestation The attestation module (

) enables you to restrict registrations to certain U2F devices (e.g. devices made by a specific vendor). It can also provide metadata for devices.

=== Serialization All relevant classes implement

, so instead of using
, you can use Java's built in serialization mechanism. Internally the classes use Jackson to serialize to and from JSON, and the ObjectMapper from Jackson can be used.

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