Thomson Licensing

Ayoub Massoudi

Alain Durand

Lionel Oisel

Mohamed Karroumi

Frederic Lefebvre

Claire-Helene Demarty

Frédéric Lefebvre

A method of encryption, using an encryption key K with key length k, of at least one message M comprising uniformly distributed symbols, k bits are encrypted of messages at least k bits long, while shorter messages are lengthened, e.g. by padding or concatenation, to obtain a lengthened message at least k bits long before encryption. The encryption efficiency is thus optimized while the encryption security is retained. The encryption method is particularly suitable for JPEG2000 encoded packets comprising a message M. Also provided are an encryption apparatus, a decryption method and a decryption apparatus.

Methods and apparatuses for selective data encryption

A method of generating a segment key KSmt from a given basic key KmT and a given modification key K'in a key space with M*T keys. The basic key KMT is split into two parts LmT, RmT onto which a one-way function is applied M&#x2212;m and T&#x2212;t times, respectively, and the results are combined again to form a target basic key. A one-way function is applied to the modification key K&#x2032;MT a number of times that corresponds to a distance value z between the given basic key and the segment key; in one preferred embodiment z=(M&#x2212;m)+(T&#x2212;t). This result is XOR-ed with the target basic key to obtain the segment key KSAlso provided is a device.

Method and device for key generation

The invention concerns a method for computing a fingerprint of a video sequence. The method comprises the steps of&#x2014;Computation of a visual digest for each frame of the video, &#x2014;Computation of the distance between the visual digest of each frame of the video in order to detect shots, &#x2014;Detection, for each detected shot of the video, of a frame, called stable frame, having the smallest content variation of the shot, &#x2014;Calculation of a local fingerprint for said stable frame.

Growing community of inventors

Issy les Moulineaux, France

Ayoub Massoudi