To avoid recourse to a certification authority and to keep a trace of delegation to a delegate by a titleholder, a terminal of the titleholder draws up a second electronic certificate different from the normal certificate of the delegate. The second certificate includes at least a delegation attribute and a signature of the data in the second certificate by means of a private key of the titleholder. The titleholder behaves like a certification authority in respect of the second certificate, which is used for cryptographic actions by the delegate in the name of the titleholder.