Example usage for com.google.common.primitives UnsignedInteger minus

Introduction

In this page you can find the example usage for com.google.common.primitives UnsignedInteger minus.

Prototype

public UnsignedInteger minus(UnsignedInteger val) 

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Document

Returns the result of subtracting this and val .

Usage

From source file:com.spotify.crtauth.CrtAuthServer.java

/**
 * Create a challenge to authenticate a given user. The userName needs to be provided at this
 * stage to encode a fingerprint of the public key stored in the server encoded in the challenge.
 * This is required because a client can hold more than one private key and would need this
 * information to pick the right key to sign the response. If the keyProvider fails to retrieve
 * the public key, a fake Fingerprint is generated so that the presence of a challenge doesn't
 * reveal whether a user key is present on the server or not.
 *
 * @param request The request message which contains an encoded username
 *
 * @return A challenge message./*w ww  .j  av a 2 s. c  o m*/
 */
public String createChallenge(String request) throws InvalidInputException {

    String userName = null;
    try {
        userName = CrtAuthCodec.deserializeRequest(request);
    } catch (DeserializationException e) {
        throw new InvalidInputException(e);
    }

    Fingerprint fingerprint;
    try {
        fingerprint = new Fingerprint(keyProvider.getKey(userName));
    } catch (KeyNotFoundException e) {
        log.info("No public key found for user {}, creating fake fingerprint", userName);
        fingerprint = createFakeFingerprint(userName);
    }

    byte[] uniqueData = new byte[Challenge.UNIQUE_DATA_LENGTH];
    UnsignedInteger timeNow = timeSupplier.getTime();
    random.nextBytes(uniqueData);
    Challenge challenge = Challenge.newBuilder().setFingerprint(fingerprint).setUniqueData(uniqueData)
            .setValidFromTimestamp(timeNow.minus(CLOCK_FUDGE))
            .setValidToTimestamp(timeNow.plus(RESPONSE_TIMEOUT)).setServerName(serverName).setUserName(userName)
            .build();
    try {
        return encode(CrtAuthCodec.serialize(challenge, secret));
    } catch (SerializationException e) {
        throw new RuntimeException(e);
    }
}

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