Abstract: The invention relates to a seal containing a substrate which can be applied to an object to be sealed, so that said seal is changed when it is removed without authorization, wherein the substrate contains or comprises a polymer and/or a glass and at least one optical waveguide is arranged in the substrate, at least one first Bragg grating being arranged in said optical waveguide, wherein the substrate has a thickness of less than 200 ?m. The invention further relates to a system having a seal of this kind and having an evaluation device, and also to a sealing method.

Abstract: The invention relates to a seal containing a substrate which can be applied to an object to be sealed, so that said seal is changed when it is removed without authorization, wherein the substrate contains or comprises a polymer and/or a glass and at least one optical waveguide is arranged in the substrate, at least one first Bragg grating being arranged in said optical waveguide, wherein the substrate has a thickness of less than 200 ?m. The invention further relates to a system having a seal of this kind and having an evaluation device, and also to a sealing method.

Abstract: A computer implemented method, computer program product, server and clients for preserving privacy and accountability. The server receives from a first client computer pseudonymous, encrypted data and stores the pseudonymous, encrypted data. The -server further receives receiving at from a second client computer a data request for the pseudonymous, encrypted data and provides the pseudonymous, encrypted data to the second client computer in response to the data request. The server receives from the second client computer a signed key request for at least one key, wherein the at least one key is configured to decrypt the pseudonymous, encrypted data and wherein the signed key request comprises a public key of the second client computer. The server receives from the first client computer the at least one key, wherein the at least one key is encrypted with the public key of the second client computer and provides the at least one encrypted key to the second client computer in response to the signed key request.

Abstract: A computer implemented method, computer program product, server and clients for preserving privacy and accountability. The server receives from a first client computer pseudonymous, encrypted data and stores the pseudonymous, encrypted data. The -server further receives receiving at from a second client computer a data request for the pseudonymous, encrypted data and provides the pseudonymous, encrypted data to the second client computer in response to the data request. The server receives from the second client computer a signed key request for at least one key, wherein the at least one key is configured to decrypt the pseudonymous, encrypted data and wherein the signed key request comprises a public key of the second client computer. The server receives from the first client computer the at least one key, wherein the at least one key is encrypted with the public key of the second client computer and provides the at least one encrypted key to the second client computer in response to the signed key request.