Digital Seal Information Matching Based On Nonstationarity Measure

Digital seals have been widely used in the fields of issuance,copyright protection and authentication.Digital seal matching is the key to authentication.Based on nonstationarity measure,we design a digital seal for matching by the random encryption method.Since the nonstationarity measure is not affected by the disturbance of noise distribution,the digital seal can execute single-blind matching and doubleblind matching security under the noise,effectively achieve the purpose of antitampering and impersonation.The digital seal can achieve better performance in validity,avoids key management,not influenced by interception and leakage during transmission,similar to ”one-time pads” for digital seal information combine with the random encryption method.This thesis made the following contributions:1.Design digital seal content.The digital seal contains time information,equipment information,content information and specific information,achieve different purpose in authentication.The digital seal is associated with the file,which solves the problem of misappropriating the seal and tampering with the file.In addition,a threechannel color digital seal is proposed based on a single-channel gray-scale digital seal,which further improves the accuracy and robustness of matching.2.For given information,an algorithm for constructing a digital seal information sequence is proposed.The information sequence is uniquely determined and the sequences of information constructed by similar information are significantly different,which improve the accuracy of matching.Based on nonstationarity measure,we construct strong noise sequences and provide metrics for matching.The digital seal is indeed an information sequence which is an information sequence and mask it with strong noise realizing random encryption.The difference between the digital seal encryption algorithm proposed in this dissertation and the existing encryption algorithm technology is: only encryption,not decryption,encryption only plays a role of masking the target information.3.According to whether the information sequence is encrypted,the digital seal is divided into single-blind matching and double-blind matching,that is,whether the matching is performed under the condition that the information sequence are encrypted.In double-blind matching,both sides of the verification cannot obtain the digital seal content,which protects sensitive information and prevents information leakage.This dissertation proposes matching algorithms and matching steps for the two matching methods.The simulation results show that: digital seals have high matching accuracy in the process of one-to-one matching and many-to-many information matching,and the matching results are robust.Three-channel digital seal has higher matching accuracy,which can accurately match information and identify the information.The experimental results are consistent with the theoretical accuracy.