| 摘要 |
FIELD: information technology. ^ SUBSTANCE: system for embedding hidden data in a printed document includes an image forming module, a points combination sequence generator module, a data embedding module and an output module. The system for extracting hidden data from a printed document includes an image capturing module, a points configuration detection module, a module for calculating distribution of frequency of unit bit values, a hidden data extracting module and an output module. Methods of embedding and extracting hidden data in a printed document describe operation of said systems. ^ EFFECT: high resistance of embedded messages to slight modifications. ^ 16 cl, 12 dwg |
