How To Collect Suggestions Safely And Secretly

Signcryption,which was first proposed by Zheng in 1997,simultaneously fulfills both the functions of digital signature and encryption in a logical single step.It needs a lower cost than the tranditional signature-then-encryption approach.Zheng's schem-e, which satisfies confidentiality and authentication,initiates signcryption's study and development.Multi-signcryption scheme is an extension of signcryption scheme for multi-signer performing together the signcryption operation on messages.It was first proposed by Shirow MITOMI and Atsuko MIYAJI in 2001.It provides useful cryptographic functions such as confidentiality and authenticity.Mitomi-Miyaji scheme,which was proposed by Shirow MITOMI and Atsuko MIYAJI, satisfies message flexibility and order flexibility,but it does not provide the message confidentiality.The sixth,nineth and twenty-fifth literatures all proposed the modified multi-signcryption schemes to achieve the message confidentiality.However,the Pang-Catianie-Tan scheme does not satisfy order flexibility,and there were not signature in the multi-signcryption process.The SL scheme does not,either.And in Zhang's scheme,the ciphertext length will be increased by the growth of the number of signcryption. This will lower transmission efficiency in the communication process.The Mitomi-Miyaji scheme and the Pang-Catianie-Tan scheme have the same defect.The main contributions of the paper are:In the proposed scheme,the multi-signcryption can be decrypted by the verifier only,and provide the message confidentiality.In the proposed scheme,the ciphertext is overlapping generated,on the one hand,this can protect the safety of the ciphertext;on the other hand,this greatly shortened the length of the final ciphertext,and improved communication in the process of transmission efficiency.