System and a method for user authentication and/or authorization

1. A system for user authentication and/or authorization, comprising:

a passive card configured to encode a first portion of an authentication or authorization code for a user via a set of capacitive points; and

a portable computing device with a capacitive screen and configured to encode a second portion of said authentication or authorization code,

wherein the set of capacitive points are connected to an electronic circuit to be activable by physical contact of the user or with an electrical ground, and

wherein the portable computing device is further configured to, based on the user requesting access to a specific service or to a specific operation, and based on at least some of the capacitive points being activated and the passive card being in contact with the capacitive screen:

read the set of capacitive points, decoding the first portion of the authentication or authorization code; and

cryptographically sign the decoded first portion using said encoded second portion of the authentication and authorization code, providing the authentication or authorization code, which is used as cryptographic key to grant access to said specific service or specific operation to the user,

wherein the first portion of the authentication or authorization code is encoded based at least on a shape and/or a size of the set of capacitive points in the passive card, and

wherein the first portion of the authentication or authorization code is encoded further based on a time constant of the set of capacitive points.

2. The system of claim 1 , wherein each capacitive point includes at least one electric resistance by which it connects to said electronic circuit.

3. The system of claim 2 , wherein electric resistances of the capacitive points are equal.

4. The system of claim 2 , wherein electric resistances of the capacitive points are different.

5. The system of claim 1 , wherein at least two of the set of capacitive points are located in predefined parts of the passive card or wherein the set of capacitive points form a unique figure.

6. The system of claim 1 , wherein the set of capacitive points are arranged divided in sets, wherein each set is connected to a different user connection point.

7. The system of claim 1 , wherein the passive card is divided into different logical areas, each one comprising a set of capacitive points encoding a different first portion, each different first portion being to authenticate a different service or to authorize a different operation.

8. The system of claim 1 , wherein the portable computing device is a mobile phone, a laptop or a tablet and wherein the second portion of the authentication or authorization code is encoded in a subscriber identification module, SIM, of the portable computing device or in a memory thereof with restricted access.

9. The system of claim 1 , wherein some of the capacitive points of the set of capacitive points include information about the user or metadata about a card distributor, the information or the metadata being encoded with an encoding system different to the encoding system used to encode the first portion of the authentication or authorization code.

10. A user authentication and/or authorization method, comprising:

encoding a first portion of an authentication or authorization code for a user through a set of capacitive points included in a passive card; and

encoding a second portion of said authentication or authorization code in a portable computing device having a capacitive screen;

wherein the method further comprises:

connecting the set of capacitive points to an electronic circuit, to be activable by physical contact of the user or with an electrical ground;

based on the user requesting access to a specific service or to a specific operation and based on at least some of the capacitive points being activated and the passive card being in contact with the capacitive screen, performing the following operations:

reading, by the portable computing device, the capacitive points, decoding the first portion of the authentication or authorization code; and

cryptographically signing, by the portable computing device, the decoded first portion using the stored second portion of the authentication or authorization code, providing the authentication or authorization code, which is used as cryptographic key for granting access to said specific service or specific operation to the user,

wherein the first portion of the authentication or authorization code is encoded based at least on a shape and/or a size of the set of capacitive points in the passive card, and

wherein the first portion of the authentication or authorization code is encoded further based on a time constant of the set of capacitive points.

11. The method of claim 10 , wherein some of the capacitive points of the set of capacitive points include information about the user or metadata about a card distributor, the information or metadata being encoded with an encoding system different to the encoding system used to store the first portion of the authentication or authorization code.

12. The method of claim 10 , wherein the set of capacitive points are arranged divided in sets, wherein each set is connected to a different user connection point.