Systems, methods and apparatus are provided for light-based authentication of a payment card. The payment card may include a randomized mix of materials. The materials may include transparent or translucent materials. A light source may shine light on a surface of the payment card. Light passing through the card may generate a light pattern that is unique to the payment card. The light pattern may be captured and compared to a reference light pattern to authenticate the payment card. In some embodiments, photodetectors may detect light patterns generated through interactions with the card materials.

A method for authenticating an object, comprising determining a physical dispersion pattern of a set of elements, determining a physical characteristic of the set of elements which is distinct from a physical characteristic producible by a transfer printing technology, determining a digital code associated with the object defining the physical dispersion pattern, and authenticating the object by verifying a correspondence of the digital code with the physical dispersion pattern, and verifying the physical characteristic.

A method for authenticating an object, comprising determining a physical dispersion pattern of a set of elements, determining a physical characteristic of the set of elements which is distinct from a physical characteristic producible by a transfer printing technology, determining a digital code associated with the object defining the physical dispersion pattern, and authenticating the object by verifying a correspondence of the digital code with the physical dispersion pattern, and verifying the physical characteristic.

A method for authenticating a security document by means of at least one device includes: a) providing the security document having at least one first security element and at least one second security element; b) providing the at least one device, wherein the at least one device includes at least one sensor; c) capturing first items of optical information of the at least one first security element by means of the at least one sensor of the at least one device during a first illumination, wherein at least one first dataset specifying these items of information is generated therefrom; d) capturing second items of optical information of the at least one second security element by means of the at least one sensor of the at least one device during a second illumination, wherein at least one second dataset specifying these items of information is generated therefrom; e) capturing third items of optical information of the at least one second security element by means of the at least one sensor of the at least one device during a third illumination, wherein at least one third dataset specifying these items of information is generated therefrom, wherein the second illumination differs from the third illumination; f) checking the genuineness of the security document and/or the second security element at least on the basis of the at least one second dataset and the at least one third dataset.

A method for classifying a banknote has at least one luminescent feature, in which the following steps are carried out: a) exciting the luminescent feature; b) recording at least a first intensity value of the excited luminescent feature at a first time and a second intensity value at a second time that is different from the first time; c) determining a decay time of the luminescent feature by approximate integration over the intensity values between the first time and the second time; d) comparing the determined decay time with a reference decay time of the luminescent feature; and e) classifying the banknote based on the comparison.

A method for classifying a banknote has at least one luminescent feature, in which the following steps are carried out: a) exciting the luminescent feature; b) recording at least a first intensity value of the excited luminescent feature at a first time and a second intensity value at a second time that is different from the first time; c) determining a decay time of the luminescent feature by approximate integration over the intensity values between the first time and the second time; d) comparing the determined decay time with a reference decay time of the luminescent feature; and e) classifying the banknote based on the comparison.

Methods and systems for optical effects in pigments, inks, and on media. One aspect of this disclosure involves a pigment particle which includes a core, having a fluorescent material and having a spherical shape, and a shell surrounding the core; the shell includes a photochromic material which has a first optical property in a first light source and a second optical property in a second light source which includes a set of wavelengths not sufficiently present in the first light source. The second optical property attenuates an emitted radiation from the fluorescent material. Other aspects are also described.

Methods and systems for optical effects in pigments, inks, and on media. One aspect of this disclosure involves a pigment particle which includes a core, having a fluorescent material and having a spherical shape, and a shell surrounding the core; the shell includes a photochromic material which has a first optical property in a first light source and a second optical property in a second light source which includes a set of wavelengths not sufficiently present in the first light source. The second optical property attenuates an emitted radiation from the fluorescent material. Other aspects are also described.

A method for authenticating an object, comprising determining a physical dispersion pattern of a set of elements, determining a physical characteristic of the set of elements which is distinct from a physical characteristic producible by a transfer printing technology, determining a digital code associated with the object defining the physical dispersion pattern, and authenticating the object by verifying a correspondence of the digital code with the physical dispersion pattern, and verifying the physical characteristic.

The present invention firstly relates to a security feature for a security or value document. The security feature comprises a zinc sulfide lurninophore in the form of particles. The zinc sulfide lurninophore has the general chemical formula ZnS: Cu.sub.x, M.sub.y, X.sub.z; here, M represents one or more elements from a group comprising the chemical elements Co, In and Ni; X represents one or more elements from a group comprising the halides F, Cl, Br and I; and the following applies: 0 < x < 0.002 and 0 ≤ y < 0.00015 and 0 ≤ z < 0.00050. The particles each have cubic phase portions and hexagonal phase portions. When excited by an electrical field, the zinc sulfide luminophore emits a first radiation in the range of the light spectrum between 580 nm and 780 nm. When excited by heating the luminophore to a temperature between 100° C. and 150° C., the zinc sulfide luminophore emits a second radiation in the light spectrum. Furthermore, the invention relates to a security and value document, which may for example be a bank note or a passport, an identity card, a driving license or a postage stamp. The invention also relates to a method for detecting and/or verifying the security feature according to the invention.