Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
84 words
A method for hiding an authentication code (101, 402, 504) in an electric
signal (100, 400, 401), which consists of data parts with a certain value, in
which method certain data parts are selected from the electric signal for
processing on the basis of the contents of the authentication code, characterized in that the value of each data part selected for processing is
re-determined by a filter (200, 403, 503), which uses certain other,
predetermined data parts of the electric signal as input data.
Claim 2
Dependent Claim
24 words
A method according to Claim 1, characterized in that said electric signal
(100, 400, 401) is a file and its data parts are bytes.
Claim 3
Dependent Claim
24 words
A method according to Claim 2, characterized in that said file is an image
file and its bytes depict the pixels of the image.
Claim 4
Dependent Claim
49 words
A method according to Claim 1, characterized in that said electric signal
(100, 400, 401) is a temporally continuous signal and its data parts are
bytes, whereby a certain temporal period is separated from the temporally
continuous signal and the authentication code is hidden in said separated
signal period.
Claim 5
Dependent Claim
21 words
A method according to Claim 4, characterized in that the authentication
code is repeatedly hidden in the same temporally continuous signal.
Claim 6
Dependent Claim
64 words
A method according to Claim 1, characterized in that a deterministic
transformation (T, 505) is also carried out on said electric signal before the
data parts are selected for processing, and a reverse transformation (T -1 ,
505) of said deterministic transformation is carried out on the transformed
electric signal after the value of each data part selected for processing has
been specified anew.
Claim 7
Independent Claim
60 words
A method for detecting the authentication coding from an electric signal,
which consists of data parts with a certain value, characterized in that in it the electric signal is filtered with a predetermined filter (403), the data parts (406) which have their value unchanged during filtering are
marked, and the marked data parts are compared to a predetermined signature (402).
Claim 8
Dependent Claim
26 words
A method according to Claim 7, characterized in that a predetermined
deterministic transformation (T) is also carried out on said electric signal
before it is filtered.
Claim 9
Independent Claim
86 words
A device for hiding the authentication code in an electric signal, which
consists of data parts with a certain value, which device comprises a
memory (501, 502) for saving said electric signal, and a processing unit
(500) for reading the electric signal from the memory and for changing the
value of its data parts, characterized in that it comprises a filter (503), and
said processing unit is arranged to re-determine the value of the data parts
selected for processing in a manner specified by said filter.
Claim 10
Independent Claim
102 words
A device for detecting the authentication coding from an electric signal,
which consists of data parts with a certain value, which device comprise a
memory (501, 502) for saving the electric signal and a processing unit (500)
for reading the electric signal from the memory and for changing the value
of its data parts, characterized in that it comprises a filter (503), and said
processing unit is arranged to re-determine the value of the data parts of the
signal in a manner specified by said filter and to save the information of
those data parts which have their value unchanged during filtering.
Claim 11
Dependent Claim
40 words
A device according to Claim 9 or 10, characterized in that it also
comprises an input device (507) for receiving the input data from the user
and an output device (506) for conveying information about the operation to
the user.
Claim 12
Dependent Claim
18 words
A device according to Claim 9 or 10, characterized in that it is a sealed
authentication coding circuit.