The invention discloses a dynamic key threshold fragmentation privacy tracing method based on block chain collaborative
verification, and belongs to the field of
information security. According to the method, a dynamic key is taken as a hub, decentralized identity, zero-knowledge
verification, deep
watermark and threshold collaborative decryption are deeply coupled, a temporary key generated by each conference is split into a plurality of fragments, the fragments are stored in a distributed manner by a block chain node and a tracing unit, only a hash
fingerprint combined by the fragments is subjected to chaining and evidence storage, and the dynamic key is subjected to zero-knowledge
verification and deep
watermark and threshold collaborative decryption. A light evidence chain which cannot be tampered but has no privacy
exposure is formed; participants are anonymously accessed through a verifiable
certificate without leaking specific information, and truth of anonymous identity is ensured through signature of a trusted unit; when data leakage occurs, the tracing unit extracts a
watermark, compares a
zero knowledge proof, verifies the relevance between a leaked
ciphertext and a chain
fingerprint, triggers a multi-party threshold decryption
recovery key, and finally accurately positions a person in charge in combination with the encrypted and stored DID mapping table without exposing irrelevant information in the whole process.