A method for encoding MPEG compatible video data for subsequent compression comprises detecting a plurality of frames of video data organized as a GOP, generating an encryption key for the GOP, and encrypting the video data using GOP-synchronized substitution, transposition, and rotation transformations...http://www.google.fr/patents/US5991403?utm_source=gb-gplus-shareBrevet US5991403 - Recoverable cryptographic transformation on YUV data suitable for compressions
Recoverable cryptographic transformation on YUV data suitable for compressions
