Research On Electronic Seal Based On Digital Watermarking And Digital Signature

Electronic seal simulates traditional seal digital with technology. The manner consistent with physical seal habits and experience use. The purpose is to ensure electronic documents and seal image security. Through electronic seal affixed electronic documents with the traditional paper documents the same appearance and effectiveness.Comparied with symmetric key encryption algorithms and asymmetric key encryption algorithm based on advantages and disadvantages. Use based MD5-RSA digital signature algorithm. Electronic documents content generated 32-bit Hash value sequence. Sender and receiver use different key encryption and decryption. Experiments show that the algorithm can detect any minor tamper with documents. Ensure that the electronic documents contents security. Watermark embeded use DWT-DCT fragile watermark algorithm. The original seal image use discrete wavelet transform to extract the wavelet coefficients of the third level. Then block them use discrete cosine transform. And make non-zero minimum value changes. Experiments show that the algorithm to small tamper detection and location accurately. Finally use LabVIEW, MATLAB, VC++ software platform combine design and development electronic seal system. The system can encrypted documents and stamped with the seal embedded watermark in sender. In receiver verifies whether the documents and seals have been tampered.Through electronic documents and seal image respectively intrusion detection experiments. The results show the digital signature algorithm use can effectively ensure documents security. Use digital watermark algorithm makes seal watermark better fragility.