A provider system is disclosed for providing a sequence of public keys to a receiver system, wherein each public key of the sequence is related to a private key and is applicable for a public key cryptography procedure. The provider system can include a computing unit and a sending unit. The computing unit can be configured to generate the sequence of public keys and related keys and compute a plurality of data sets, where a data set of the plurality of data sets includes a public key and a proof value. The proof values can result from applying a hash function to a following data set that includes a further public key following in the sequence. The sending unit can be configured to provide the plurality of data to a receiver system.