@article{paperid:1030071, author = {Mehrnejad, Maryam and Ghaemi Bafghi, Abbas and Harati, Ahad and Ehsan Toreini}, title = {SEIMCHA: A New Semantic Image CAPTCHA Using Geometric Transformations}, journal = {ISeCure}, year = {2012}, volume = {4}, number = {1}, month = {January}, issn = {2008-2045}, pages = {63--76}, numpages = {13}, keywords = {Component; SEIMCHA; Semantic Image CAPTCHA; Security; Usability; Geometric Transformation; Upright Orientation; Tagging Image CAPTCHA; Random Guessing.}, }