“…In the same year, Yi et al [12] proposed the concept of proxy multi-signature, in such a scheme, a group of original signers can delegate their signing capability to a proxy signer. In 2001, Hwang et al [13] proposed the concept of multi-proxy multi-signature, in such a scheme, a group of original signers can delegate their signing capabilities to a group of proxy signers. In 2003, Li et al [14] proposed the concept of threshold proxy threshold signature, in which original signers can cooperatively delegate the signing capabilities to a group of proxy signers, and In addition, proxy signature can combine other special signatures to obtain some new types of proxy signature, such as designated verifier proxy signature [15], proxy blind signature [16], forward security proxy signature [17], ID-based proxy signature [18] and certificateless proxy signature [19] et al…”