An Immunity Passport Scheme Based on the Dual-Blockchain Architecture for International Travel

Table 1

Notations in the scheme.

Notations	Description
	User
	Multiplicative cyclic groups
	Secure hash function
	Public and private key pair of KGC
	Public and private key pair of IBC
	Public and private key pair of user
	Partial-private key
	Pseudoidentity of user
	Identity of the country
	ID of the DBC-block
	Index of keyword
	Ciphertext of the passport
	Key confirmation message
	Decryption key
	Trapdoor