System, device, and method of voice-based user authentication utilizing a challenge

A system comprising:

• a voice-based user-authentication unit, to authenticate a user based on a voice sample uttered by said user;
• a voice-related challenge generator, to generate a voice-related challenge that induces said user to modify one or more vocal properties of said user;
• a reaction-to-challenge detector, to detect a user-specific vocal modification in reaction to said voice-related challenge;
• wherein the voice-based user-authentication unit utilizes said user-specific vocal modification, that was detected as reaction to said voice-related challenge, as part of a user-authentication process that either approves or denies authentication of said user;
• wherein the voice-related challenge generator comprises an ambient sound volume-increase module which is operable to increase a playback volume of an already-existing ambient sound while said user is uttering speech;
• wherein the reaction-to-challenge detector comprises a microphone, selected from the group consisting of:
• (i) an acoustic microphone, (ii) an optical microphone, (iii) a hybrid acoustic-and-optical microphone device,
• wherein said microphone and an associated processor are operable to detect and to characterize user-specific vocal features exhibited by said user in reaction to said increase in the volume of an already-existing ambient sound.

A system comprising:

• a voice-based user-authentication unit, to authenticate a user based on a voice sample uttered by said user;
• a voice-related challenge generator, to generate a voice-related challenge that induces said user to modify one or more vocal properties of said user;
• a reaction-to-challenge detector, to detect a user-specific vocal modification in reaction to said voice-related challenge;
• wherein the voice-based user-authentication unit utilizes said user-specific vocal modification, that was detected as reaction to said voice-related challenge, as part of a user-authentication process that either approves or denies authentication of said user;
• wherein the voice-related challenge generator comprises an interfering speech injector module which is operable to inject a playback of an interfering speech-segment while said user is uttering speech;
• wherein the reaction-to-challenge detector comprises a microphone, selected from the group consisting of:
• (i) an acoustic microphone, (ii) an optical microphone, (iii) a hybrid acoustic-and-optical microphone device, wherein said microphone and an associated processor are operable to detect and to characterize user-specific vocal features exhibited by said user in reaction to said injected interfering speech-segment.