A method for executing a payment using a first mobile portable terminal of a plurality of mobile portable terminals and a blockchain system, wherein the blockchain system comprises a plurality of blockchains (148, 149, 167), wherein each of the blockchains (148, 149, 167) is assigned to one or more blockchain servers (140, 141, 161), which manage the corresponding blockchain (148, 149, 167), wherein each mobile portable terminal of the plurality of mobile portable terminals is assigned a respective serial number from a space of serial numbers, wherein the space of serial numbers is divided into a plurality of ranges of serial numbers, wherein each of the ranges of serial numbers is assigned a respective one of the blockchains (148, 149, 167) of the blockchain system which logs payments from blockchain addresses assigned to mobile portable terminals with serial numbers from the corresponding range of serial numbers, wherein the method comprises: • receiving a message of the first mobile portable terminal with a transaction release, wherein the transaction release is signed using a private cryptographic key of an asymmetric key pair of the first mobile portable terminal, wherein the asymmetric key pair is assigned to a first blockchain address of the first mobile portable terminal, wherein the transaction release comprises the first blockchain address of the first mobile portable terminal, a second blockchain address of the payee and an amount to be paid, • determining, using a first serial number of the first mobile portable terminal comprising the message, a first blockchain of the plurality of blockchains (148, 149, 167) associated with the range of serial numbers comprising the first serial number, • forwarding the message to a first blockchain server, which manages the particular first blockchain, for checking and entering the transaction released by the transaction release into the first blockchain. wherein the blockchain system comprises a plurality of blockchains (148, 149, 167), wherein each of the blockchains (148, 149, 167) is assigned to one or more blockchain servers (140, 141, 161), which manage the corresponding blockchain (148, 149, 167), wherein each mobile portable terminal of the plurality of mobile portable terminals is assigned a respective serial number from a space of serial numbers, wherein the space of serial numbers is divided into a plurality of ranges of serial numbers, wherein each of the ranges of serial numbers is assigned a respective one of the blockchains (148, 149, 167) of the blockchain system which logs payments from blockchain addresses assigned to mobile portable terminals with serial numbers from the corresponding range of serial numbers, wherein the method comprises: • receiving a message of the first mobile portable terminal with a transaction release, wherein the transaction release is signed using a private cryptographic key of an asymmetric key pair of the first mobile portable terminal, wherein the asymmetric key pair is assigned to a first blockchain address of the first mobile portable terminal, wherein the transaction release comprises the first blockchain address of the first mobile portable terminal, a second blockchain address of the payee and an amount to be paid, • determining, using a first serial number of the first mobile portable terminal comprising the message, a first blockchain of the plurality of blockchains (148, 149, 167) associated with the range of serial numbers comprising the first serial number, • forwarding the message to a first blockchain server, which manages the particular first blockchain, for checking and entering the transaction released by the transaction release into the first blockchain. • receiving a message of the first mobile portable terminal with a transaction release, wherein the transaction release is signed using a private cryptographic key of an asymmetric key pair of the first mobile portable terminal, wherein the asymmetric key pair is assigned to a first blockchain address of the first mobile portable terminal, wherein the transaction release comprises the first blockchain address of the first mobile portable terminal, a second blockchain address of the payee and an amount to be paid, • determining, using a first serial number of the first mobile portable terminal comprising the message, a first blockchain of the plurality of blockchains (148, 149, 167) associated with the range of serial numbers comprising the first serial number, • forwarding the message to a first blockchain server, which manages the particular first blockchain, for checking and entering the transaction released by the transaction release into the first blockchain.