摘要:
Selective data encryption of a file, in particular an H.264/MPEG-4 AVC data stream. If a first unit in the data stream is to be encrypted, it is encrypted and the encryption is put into a further unit, preferably in the data stream. A substitution unit is generated and put in the place of the first unit; if necessary, at least one header value is taken from the first unit for use in the substitution unit. A decryptor receives the encrypted data stream, extracts and decrypts the further unit and replaces the substitution unit with a regenerated first unit.
摘要:
Selective data encryption of a file, in particular an H.264/MPEG-4 AVC data stream. If a first unit in the data stream is to be encrypted, it is encrypted and the encryption is put into a further unit, preferably in the data stream. A substitution unit is generated and put in the place of the first unit; if necessary, at least one header value is taken from the first unit for use in the substitution unit. A decryptor receives the encrypted data stream, extracts and decrypts the further unit and replaces the substitution unit with a regenerated first unit.
摘要:
The invention relates to a method for watermarking at least one timestamp in a set of support data, comprising the following steps for each timestamp: association with the timestamp of the value at a given time of a reference timestamp signal, that is a determinist signal varying over time in a given temporal reference and being written as s(t), wherein t is incremented according to an incrementing step equal to one predetermined time unit; and watermarking of the value in the set of support data. The invention also relates to a corresponding decoding method comprising the following steps: reading, in the set of support data, of at least one value of a phase-shifted timestamp signal, of the same form as the reference timestamp signal but having in relation to this signal an unknown phase shift φ in a given temporal reference, the previous watermarking of each timestamp consisting in a watermarking of the value at a given watermarking time of the reference timestamp signal; estimation of the phase shift φ from the at least one read value of the phase-shifted timestamp signal and from the knowledge of the reference timestamp signal; and for the at least one read value, read at a given time tr, determination of an associated timestamp h associated according to the read time tr and the estimated phase shift φ.
摘要:
The invention relates to a method of watermarking a data set comprising the steps of: selecting, in the data set, at least one group of two data; and modifying at least one data of the group. The data is modified such that the difference between the modified data and the other data of the group possibly modified equals a predefined watermarking parameter multiplied by an integer number, called rejection class, associated with the group and equal to the integer nearest to the ratio between the difference between the at least one data and the other data of the group before the modification divided by the watermarking parameter.
摘要:
The invention relates in particular to a stream-wise method of watermarking independent of the compression parameters used (for example type of the transform) so as to allow the reading of the watermarking inserted independently of the format of the data received. The watermarking method according to the invention consists in generating a contribution matrix in the transformation space, in projecting it into another domain and in watermarking the data in this domain on the basis of the projected matrix so as to allow a watermark reader operating in the transformed transformation space to read back the inserted watermarking in the transformation space. The contribution matrix representing the modifications induced on the coefficients in the transformation space by insertion of the watermarking cue in this same domain.
摘要:
The invention relates to a method of watermarking a binary stream resulting from the encoding of a set of coefficients comprising at least one coefficient encoded by predictive coding, called predictively coded coefficient. The method comprises the steps of: a) identifying, in the binary stream, a first binary word representing the predictively coded coefficient; b) computing a modified coefficient from the predictively coded coefficient on the basis of at least one watermarking bit; c) encoding the modified coefficient into a second binary word; and d) replacing in the binary stream the first binary word with the second binary word.
摘要:
The invention relates to a method of reading a watermark, of the type comprising a step of determining at least one watermarking message contained in a data set, possibly preceded by a step of determining at least one suite of parameters of a watermarking channel undergone by the data set, each suite of channel parameters comprising at least one channel parameter. The step of determining at least one watermarking message and/or the prior step of determining at least one suite of channel parameters comprises (comprise): an estimation phase, consisting in processing at least one batch of data comprising data of the data set, so as to obtain N estimated element(s), with N≧0; and a verification phase, consisting in validating or invalidating, in view of the entirety or of at least a subset of the data set, each estimated element. In the foregoing, each estimated element is an estimated watermarking message, in the case of the step of determining at least one watermarking message, and a suite of estimated-channel parameters, in the case of the prior step of determining at least one suite of channel parameters.
摘要:
The invention relates to a method of watermarking a binary stream resulting from the encoding of a set of coefficients comprising at least one coefficient encoded by predictive coding, called predictively coded coefficient. The method comprises the steps of: a) identifying, in the binary stream, a first binary word representing the predictively coded coefficient; b) computing a modified coefficient from the predictively coded coefficient on the basis of at least one watermarking bit; c) encoding the modified coefficient into a second binary word; and d) replacing in the binary stream the first binary word with the second binary word.
摘要:
In a device and a method for the determining local geometrical variations that have occurred in data, the data comprise a reference pattern X. The method comprises, for example, the following steps: modeling the local geometrical variations by means of an index variable J, said variable making it possible to place the samples of the distorted data in correspondence with those of the original data, estimating the local variations by using the reference pattern X included, a model of local distortion of the data and the distorted data.
摘要:
The invention relates to a method of watermarking a data set comprising the steps of: selecting, in the data set, at least one group of two data; and modifying at least one data of the group. The data is modified such that the difference between the modified data and the other data of the group possibly modified equals a predefined watermarking parameter multiplied by an integer number, called rejection class, associated with the group and equal to the integer nearest to the ratio between the difference between the at least one data and the other data of the group before the modification divided by the watermarking parameter.