In a method and a device for partial encryption and progressive transmission of images, a first section of the image file is compressed at reduced quality without decryption, and a second section of the image file is encrypted. Users having access to appropriate decryption keywords can decrypt this second...http://www.google.fr/patents/US6931534?utm_source=gb-gplus-shareBrevet US6931534 - Method and a device for encryption of images
