A method (100, 200, 300) for operating a network slice management function configured to manage a network slice of a cellular network, the method performed by a communication network device hosting the network slice management function, the method comprising: - receiving (102, 202) a request for a network slice, the request including a specified end-to-end slice quantum protection level, QPL, for the network slice; - requesting (104, 204), from a security management entity of the cellular network, allocation of network components having component QPLs at least equal to the specified slice QPL, a component QPL being indicative of a level of security, against an attack operated by a quantum computer, provided to the network component by quantum-resistant technology when the network component is using the quantum-resistant technology; - receiving (106, 206), from the security management entity, information identifying allocated network components; - instantiating (108, 212) the network slice using network components of the allocated network components; and - following instantiation of the network slice, periodically determining a current slice QPL of the network slice and performing one of the following depending on the current slice QPL: - no action required; - perform active monitoring of the network slice and start actions to update network slice components when the current slice QPL is below a threshold slice QPL value; - inform a Service Provider requesting the network slice that the current network slice QPL is less than the specified slice QPL; and - stop operation of the network slice and move a Service using the network slice to another slice having a slice QPL at least equal to the specified slice QPL. - receiving (102, 202) a request for a network slice, the request including a specified end-to-end slice quantum protection level, QPL, for the network slice; - requesting (104, 204), from a security management entity of the cellular network, allocation of network components having component QPLs at least equal to the specified slice QPL, a component QPL being indicative of a level of security, against an attack operated by a quantum computer, provided to the network component by quantum-resistant technology when the network component is using the quantum-resistant technology; - receiving (106, 206), from the security management entity, information identifying allocated network components; - instantiating (108, 212) the network slice using network components of the allocated network components; and - following instantiation of the network slice, periodically determining a current slice QPL of the network slice and performing one of the following depending on the current slice QPL: - no action required; - perform active monitoring of the network slice and start actions to update network slice components when the current slice QPL is below a threshold slice QPL value; - inform a Service Provider requesting the network slice that the current network slice QPL is less than the specified slice QPL; and - stop operation of the network slice and move a Service using the network slice to another slice having a slice QPL at least equal to the specified slice QPL. - no action required; - perform active monitoring of the network slice and start actions to update network slice components when the current slice QPL is below a threshold slice QPL value; - inform a Service Provider requesting the network slice that the current network slice QPL is less than the specified slice QPL; and - stop operation of the network slice and move a Service using the network slice to another slice having a slice QPL at least equal to the specified slice QPL.