A method comprising: receiving, by a blockchain maintainer, a client request for a cryptographic token, the cryptographic token to allow the client to access a particular service from a service provider; processing, by the blockchain maintainer, the request using a blockchain smart contract to determine if the client request is valid; if the client request is determined to be valid, including the client request in the blockchain; generating, by a token issuer, the requested cryptographic token in response to inclusion of the valid client request in the blockchain; and issuing the generated cryptographic token to the client.