Cryptanalysis of a Publicly Verifiable Threshold Secret Sharing Scheme

By means of theoretical analyzing and experimental verifying, two flaws in the public verifiable threshold proactive secret sharing scheme proposed by Shi Runhua, are found.First, the value of threshold k can not be trusted.Second, the attackers can crack the secrets S in terms of public shares update algorithm.At last, new analyzing methods for proactive secret sharing scheme are proposed, which can conduct comprehensive analysis of forward-threshold secret sharing scheme by extending the completeness of proactive secret sharing scheme, and the unidirection of shares updated algorithm.