Liveness detection

A liveness detection system comprising:

• a set of one or more hardware processing units, the set configured to perform operations of:
• selecting at random a first set of one or more parameters of a first liveness test;
• transmitting, to a user device available to an entity, the first parameter set, thereby causing the user device to perform the first liveness test according to the first parameter set;
• receiving from the user device results of the first liveness test performed at the user device according to the first parameter set;
• receiving results of a second liveness test pertaining to the entity;
• detecting whether a timeout condition has occurred, the timeout condition caused by an unacceptable delay in receiving the results relative to a timing of the transmitting operation;
• and
• if the timeout condition occurs, refusing the entity access to a remote computer system in response to the timeout condition occurring, otherwise determining whether the entity is a living being using the results of the liveness tests, the results of the first liveness test being so used by comparing them with the first parameter set.

A computer-implemented liveness detection method implemented by a liveness detection system, wherein the liveness detection system comprises a hardware processor and computer storage storing a shared secret known only to the liveness detection system and one or more authorized user devices, the method comprising implementing by the liveness detection system the following steps:

• selecting at random a set of one or more parameters of a liveness test which, when combined with the shared secret, define expected outputs that should be provided in the liveness test;
• transmitting the parameter set to a user device, thereby causing the user device to perform the liveness test according to the parameter set, whereby the user device can only provide the expected outputs therein if it also has access to its own version of the shared secret;
• receiving from the user device results of the liveness test performed at the user device according to the first parameter set;
• detecting whether a timeout condition has occurred, the timeout condition caused by an unacceptable delay in receiving the results relative to a timing of the transmitting step;
• and
• if the timeout condition occurs, refusing the entity access to a remote computer system in response to the timeout condition occurring, otherwise:
• using the parameter set and the shared secret stored at the liveness detection system to determine the expected outputs;
• and
• comparing the results of the liveness test with the determined expected outputs to determine whether a behaviour of an entity that was subject to the liveness test performed at the user device is an expected reaction to the expected outputs, thereby determining from the entity's behaviour both whether the entity is a living being and whether the user device is one of the one or more authorized user devices.

A liveness detection system comprising:

• computer storage storing a shared secret known only to the liveness detection system and one or more authorized user devices;
• and
• a set of one or more hardware processing units, the set configured to perform operations of:
• selecting at random a set of one or more parameters of a liveness test which, when combined with the shared secret, define expected outputs that should be provided in the liveness test;
• transmitting the parameter set to a user device, thereby causing the user device to perform the liveness test according to the parameter set, whereby the user device can only provide the expected outputs therein if it also has access to its own version of the shared secret;
• receiving from the user device results of the liveness test performed at the user device according to the first parameter set;
• detecting whether a timeout condition has occurred, the timeout condition caused by an unacceptable delay in receiving the results relative to a timing of the transmitting step;
• and
• if the timeout condition occurs, refusing the entity access to a remote computer system in response to the timeout condition occurring, otherwise:
• using the parameter set and the shared secret stored at the liveness detection system to determine the expected outputs;
• and
• comparing the results of the liveness test with the determined expected outputs to determine whether a behaviour of an entity that was subject to the liveness test performed at the user device is an expected reaction to the expected outputs, thereby determining from the entity's behaviour both whether the entity is a living being and whether the user device is one of the authorized user device(s).

Non-transitory computer readable media comprising computer readable instructions which, when executed by a hardware processor, cause the hardware processor to implement a method comprising:

• selecting at random a first set of one or more parameters of a first liveness test;
• transmitting, to a user device available to an entity, the first parameter set, thereby causing the user device to perform the first liveness test according to the first parameter set;
• receiving from the user device results of the first liveness test performed at the user device according to the first parameter set;
• receiving results of a second liveness test pertaining to the entity;
• detecting whether a timeout condition has occurred, the timeout condition caused by an unacceptable delay in receiving the results relative to a timing of transmitting the first parameter set;
• and
• if the timeout condition occurs, refusing the entity access to a remote computer system in response to the timeout condition occurring, otherwise determining whether the entity is a living being using the results of the liveness tests, the results of the first liveness test being so used by comparing them with the first parameter set.