A method performed by a first apparatus and a further apparatus, comprising, performed by the first apparatus: - providing first identity data stored in the first apparatus, the first identity data comprising an identifier and a first certificate, and - providing second identity data stored in the first apparatus, the second identity data comprising an identifier and a second certificate, - wherein the identifier of the first identity data is the same as the identifier of the second identity data, wherein said providing the first identity data comprises transmitting the first identity data to the further apparatus and wherein said providing the second identity data comprises transmitting the second identity data to the further apparatus, wherein the identifier of the first identity data is part of the first certificate and wherein the identifier of the second identity data is part of the second certificate; and wherein the method comprises, performed by the further apparatus, verifying trustworthiness of the first apparatus being associated with first identity data and second identity data, the first identity data comprising an identifier and a first certificate and the second identity data comprising an identifier and a second certificate, wherein said verifying trustworthiness is based on verifying at least partially the first identity data and the second identity data which only leads to a positive result if the identifier of the first identity data is the same as the identifier of the second identity data; wherein said verifying the first identity data comprises determining whether the first certificate is valid and wherein said verifying the second identity data comprises determining whether the second certificate is valid; and wherein the first certificate is a certificate being associated with a first party and the second certificate is a certificate being associated with a second party. - providing first identity data stored in the first apparatus, the first identity data comprising an identifier and a first certificate, and - providing second identity data stored in the first apparatus, the second identity data comprising an identifier and a second certificate, - wherein the identifier of the first identity data is the same as the identifier of the second identity data, wherein said providing the first identity data comprises transmitting the first identity data to the further apparatus and wherein said providing the second identity data comprises transmitting the second identity data to the further apparatus, wherein the identifier of the first identity data is part of the first certificate and wherein the identifier of the second identity data is part of the second certificate; and wherein the method comprises, performed by the further apparatus, verifying trustworthiness of the first apparatus being associated with first identity data and second identity data, the first identity data comprising an identifier and a first certificate and the second identity data comprising an identifier and a second certificate, wherein said verifying trustworthiness is based on verifying at least partially the first identity data and the second identity data which only leads to a positive result if the identifier of the first identity data is the same as the identifier of the second identity data; wherein said verifying the first identity data comprises determining whether the first certificate is valid and wherein said verifying the second identity data comprises determining whether the second certificate is valid; and wherein the first certificate is a certificate being associated with a first party and the second certificate is a certificate being associated with a second party. wherein the identifier of the first identity data is part of the first certificate and wherein the identifier of the second identity data is part of the second certificate; and wherein the method comprises, performed by the further apparatus, verifying trustworthiness of the first apparatus being associated with first identity data and second identity data, the first identity data comprising an identifier and a first certificate and the second identity data comprising an identifier and a second certificate, wherein said verifying trustworthiness is based on verifying at least partially the first identity data and the second identity data which only leads to a positive result if the identifier of the first identity data is the same as the identifier of the second identity data; wherein said verifying the first identity data comprises determining whether the first certificate is valid and wherein said verifying the second identity data comprises determining whether the second certificate is valid; and wherein the first certificate is a certificate being associated with a first party and the second certificate is a certificate being associated with a second party.