A pair of virtualized security device initialization data sets are received at a first virtualization server from respective sources prior to a launch of a compute instance at the server. A first virtualized security device is initialized using the data sets, and used to generate cryptographic artifacts used by the compute instance. A data item which was included in one of the data sets is modified after the cryptographic artifacts are generated. Additional cryptographic artifacts are generated by a second virtualized security device at a second virtualization server to which the compute instance has been migrated. The second virtualized security device is initialized using at least the modified data item.