Rumor or abusive web postings in internet has become a social issue. Web postings may be proposed on evidence in form of a screenshot in libel suit, but a screenshot can be easily modified by computer programs. A person can make ill use of the screenshot which is modified deliberately original contents to opposite meaning in a lawsuit. That makes an innocent person to be punished because it can have difficulties to verify despite analyzing the server data. A screenshot of web postings is likely to fail to prove its authenticity and it is not able to reflect the fact. If notarization for web postings is offered, clear and convincing evidence can be submitted in a court. So, related techniques and policies should be established In this paper, we propose some technical and legal conditions and design for notarization and archive system of web postings for litigation.