A method comprising: prior to an interaction between a resource provider computer (106, 722, 922) and a user device: receiving, by a gateway computer (112, 200, 514, 726, 928), a credential from the resource provider computer; transmitting, by the gateway computer, the credential to a token server computer (110, 516, 732); receiving, by the gateway computer, a data item from the token server computer, the data item having been generated by the token server and comprising a first ciphertext and a second ciphertext; generating, by the gateway computer, a token based on the data item; storing, by the gateway computer, the data item in a database (206, 730) in association with the token; transmitting, by the gateway computer, the token to the resource provider computer, wherein the resource provider computer stores the token; receiving, by the gateway computer (112, 200, 514, 726, 928), the token from an edge computer (108, 300, 518, 926) during an interaction between the resource provider computer (106, 722, 922) and the user device, the resource provider computer having transmitted the token to the edge computer; determining, by the gateway computer, the data item comprising the first ciphertext and the second ciphertext associated with the token from the database; transmitting, by the gateway computer, the second ciphertext to the edge computer; receiving, by the gateway computer, a re-encrypted second ciphertext from the edge computer, the edge computer having produced the re-encrypted second ciphertext by re-encrypting the second ciphertext with a re-encryption key corresponding to the gateway computer, the re-encryption key having been distributed by the token server computer after having been generated based on a gateway computer public key and a token server computer private key by the token server computer; decrypting, by the gateway computer, the re-encrypted second ciphertext with a gateway computer private key to obtain a cryptographic key; decrypting, by the gateway computer, the first ciphertext with the cryptographic key to obtain the credential; and transmitting, by the gateway computer, the credential to an authorizing entity computer (116, 936) for determination by the authorizing entity computer of whether or not to authorize the interaction. prior to an interaction between a resource provider computer (106, 722, 922) and a user device: receiving, by a gateway computer (112, 200, 514, 726, 928), a credential from the resource provider computer; transmitting, by the gateway computer, the credential to a token server computer (110, 516, 732); receiving, by the gateway computer, a data item from the token server computer, the data item having been generated by the token server and comprising a first ciphertext and a second ciphertext; generating, by the gateway computer, a token based on the data item; storing, by the gateway computer, the data item in a database (206, 730) in association with the token; transmitting, by the gateway computer, the token to the resource provider computer, wherein the resource provider computer stores the token; receiving, by a gateway computer (112, 200, 514, 726, 928), a credential from the resource provider computer; transmitting, by the gateway computer, the credential to a token server computer (110, 516, 732); receiving, by the gateway computer, a data item from the token server computer, the data item having been generated by the token server and comprising a first ciphertext and a second ciphertext; generating, by the gateway computer, a token based on the data item; storing, by the gateway computer, the data item in a database (206, 730) in association with the token; transmitting, by the gateway computer, the token to the resource provider computer, wherein the resource provider computer stores the token; receiving, by the gateway computer (112, 200, 514, 726, 928), the token from an edge computer (108, 300, 518, 926) during an interaction between the resource provider computer (106, 722, 922) and the user device, the resource provider computer having transmitted the token to the edge computer; determining, by the gateway computer, the data item comprising the first ciphertext and the second ciphertext associated with the token from the database; transmitting, by the gateway computer, the second ciphertext to the edge computer; receiving, by the gateway computer, a re-encrypted second ciphertext from the edge computer, the edge computer having produced the re-encrypted second ciphertext by re-encrypting the second ciphertext with a re-encryption key corresponding to the gateway computer, the re-encryption key having been distributed by the token server computer after having been generated based on a gateway computer public key and a token server computer private key by the token server computer; decrypting, by the gateway computer, the re-encrypted second ciphertext with a gateway computer private key to obtain a cryptographic key; decrypting, by the gateway computer, the first ciphertext with the cryptographic key to obtain the credential; and transmitting, by the gateway computer, the credential to an authorizing entity computer (116, 936) for determination by the authorizing entity computer of whether or not to authorize the interaction.