1. A method for speaker verification comprising using at least one hardware processor for: providing a development set comprising multiple human voice samples of multiple human speakers uttering a predefined development text; recording, using a microphone, a reference sample of a target speaker uttering a reference text; prompting, using an output device selected from the group consisting of a loudspeaker and a display, a test text to the target speaker, wherein said test text and said reference text are different from said predefined development text, and wherein said prompting is performed after said reference sample recording; recording, using a microphone, a test sample of the target speaker uttering the test text; synthesizing a set of simulated human voice samples based on said multiple human voice samples, wherein each of said simulated human voice samples simulates a different human speaker of said multiple human speakers uttering the test text, wherein said synthesizing comprises text splicing; computing a universal background model from said synthesized simulated human voice samples; and verifying an identity of said target speaker based on said universal background model and on said reference sample and test sample of the target speaker.