Koninklijke Philips Corporation N.v.

U.S. Philips Corporation

Other

Intrinsic Id B.v.

Marten Erik Van Dijk

Constant P M J Baggen

Kouhei Yamamoto

Willem M J M Coene

Pim Theo Tuyls

Constant Paul Marie Jozef Baggen

Ludovicus M G M Tolhuizen

Masayuki Hattori

Tatsuya Narahara

Ludovicus Marinus Gerardus Maria Tolhuizen

Willem Marie Julia Marcel Coene

Johan P M G Linnartz

Josephus A H M Kahlman

Petrus Johannes Lenoir

Antonius A C M Kalker

Maurice J J J-b Maes

Franciscus Maria Joannes Willems

Evgeny Verbitskiy

Peter M J Rongen

Berry Schoenmakers

Geert F G Depovere

Hendrik D L Hollmann

Susumu Senshu

Christianus W F Vriens

Masayuk Hattori

The present invention relates to a method and a system of securely computing a measure of similarity for at least two sets of data. A basic idea of the present invention is to securely compare two sets of encrypted data to determine whether the two sets of data resemble each other to a sufficient extent. If the measure of similarity complies with predetermined criteria, the two sets of data from which the encrypted sets of data originate are considered to be identical.

Securely computing a similarity measure

A physical random function (PUF) is a function that is easy to evaluate but hard to characterize. Controlled physical random functions (CPUFs) are PUFs that can only be accessed via a security program controlled by a security algorithm that is physically bound to the PUF in an inseparable way. CPUFs enable certified execution, where a certificate is produced that proves that a specific computation was carried out on a specific processor. The invention provides an additional layer for generating a proof of execution which any third party can verify. This proof of execution is also useful to provide secure memory and secure interruptible program execution.

Proof of execution using random function

A secure solution is provided to the problem of secret key agreement. In particular, a method of reliable forward secret key sharing is disclosed between two legitimate correspondents whose profiles match sufficiently. The invention relies on a physical random function, sometimes referred to as a physical unclonable function (PUF) to provide a secure solution to the problem of secret key agreement. In one embodiment, a one-pass protocol is introduced based on Reed-Solomon codes leading to an unconditionally secure solution. In a further embodiment, the solution of the first embodiment is improved upon by providing a conditionally secure solution based on a pseudo random family of functions. In a still further embodiment, a two-pass protocol is introduced which is used exclusively for purposes of identification and authentication. In accordance with the principles of the two-pass protocol, two communications are required and unlike the one-pass protocol, the second correspondent selects the secret key K.

System and method of reliable forward secret key sharing with physical random functions

Information signals such as grayscale images or audio signals are represented as a sequence of PCM signal samples. To embed auxiliary data in the least significant bits of the signal, the samples are slightly distorted. There is a so-termed 'rate-distortion function' () which gives the largest embedding rate R given a certain distortion level D. It appears that the efficiency of prior art embedding schemes such as LSB replacement () can be improved. The invention discloses such embedding schemes (). According to the invention, the signal is divided into groups of L (L&#x3e;1) signal samples (x). For each group of signal samples, a vector of least significant portions (x mod n) of the signal samples is created. For n=2, the vector comprises the least significant bit of each signal sample. The syndrome of said vector (as defined in the field of error detection and correction) represents the embedded data. Only one (or a few, in any case less than L) signal sample(s) of a group needs to be modified so as to achieve that the vector assumes a desired syndrome value.

Embedding auxiliary data in an information signal

A method of embedding an additional layer of error correction into an error correcting code, wherein information is encoded into code words of said code over a first Galois field and wherein a number of code words are arranged in the columns of a code block comprising a user data sub-block and a parity data sub-block, provides an additional layer of error correction that can be easily implemented without losing compatibility improving the error correction capabilities. The method includes the steps of:

Method and apparatus for embedding an additional layer of error correction into an error correcting code

A method of embedding an additional layer of error correction into an error correcting code, where information is encoded into code words that are arranged in columns of a code block. The method includes reducing the length of each row of the code block by adding row symbols together according to a predetermined adding rule resulting in a reduced code block; encoding the shortened rows of the reduced code block using a horizontal error correcting code to obtain horizontal parities; and embedding the horizontal parities as additional layer in the error correcting code.

The invention relates to a method of storing a number of data bits of a secondary channel () in the frame of a main channel () and to a method of decoding a stream of bits relating to a secondary channel () embedded in the frames of a main channel () into a stream of data bits (). In order to enable a certain synchronization and to guarantee a fixed amount of storage capacity in the secondary channel as well as to be able to correct deletions or insertions of bits in the secondary channel it is proposed according to the invention to form a secondary frame () having a fixed number of frame bits, to fill a fixed part of the secondary frame () with data bits (), an end-bit () set to a first bit-value and, if necessary, with filling bits () set to a second bit-value, to encode the secondary frame () producing encoded data bits () and parity bits (), which are finally embedded in the frame of the main channel (). The invention relates also to a device for storing a number of data bits of the secondary channel () in the frame of a main channel () and to a device for decoding a stream of bits of relating to a secondary channel () embedded in the frames of a main channel ().

Method of storing or decoding a stream of bits

A method of selecting a generator matrix (G) for encoding information words (m) including information symbols (m, m, m) into codewords (c) of a code (C) provides an enhanced error correction capability if at least one information symbol (m, m, m) is known a priori to a decoder decoding received, possibly mutilated codewords (r). In order to design a code of which the correction power is enhanced if some information symbols are known to the decoder prior to decoding, the generator matrix (G) is selected such that the minimum Hamming distance of at least one subcode (C') of the code (C) is larger than the minimum Hamming distance of the code (C), and that a subcode generator matrix (G&#x2032;) of the at least one subcode (C&#x2032;) is derived from the generator matrix (G) of the code (C) by omitting the at least one row from the generator matrix (G) corresponding to the at least one a priori known information symbol (m, m, m).

Coding for informed decoders

An information carrier includes runlength limited marks in a track. The runlengths of the marks represent main channel bits and variations of a further parameter of the marks representing secondary channel bits. Not all marks have the variations, only marks of at least a predetermined runlength have the variations.

Information carrier, device for encoding, method for encoding, device for decoding and method for decoding

A watermark detector is disclosed to judge whether multimedia content can be copied or not. The watermark detector examines the multimedia content and outputs a signal indicating whether a watermark is present or not. A decision variable indicating to which extent the watermark is present is determined, for example, the amount of correlation between the input signal and a reference copy of the watermark to be detected. The watermark is detected if the decision variable exceeds a predetermined threshold (y ). The detector also generates a random output signal for a predetermined range of decision values between the threshold (y ) and a further threshold (y ).

Device for optically scanning a record carrier

Multiword information is encoded as based on multibit symbols in relative contiguity with respect to a medium, whilst providing wordwise interleaving and wordwise error protection code facilities. This may provide error locative clues across words of multiword groups, that originate in high protectivity clue words and point to low protectivity target words. The clue words may have a first uniform size and be interspersed in a first uniform manner. The target words may have a second uniform size and be interspersed in a second uniform manner. The organization may be applied for use with optical storage. Sectors may get provisional protectivity as a low-latency error correction mechanism.

Method and apparatus for encoding multiword information with error locative clues directed to low protectivity words

Multiword information is based on multibit symbols disposed in relative contiguity with respect to a medium, and is encoded with a wordwise interleaving and wordwise error protection code for providing error locative clues across multiword groups. In particular, the clues originate in high protectivity clue words (BIS) that are interleaved among clue columns, and also in synchronizing columns constituted from synchronizing bit groups. The synchronizing columns are located where the clue columns are relatively scarcer disposed. The clues are directed to low protectivity target words (LDS) that are interleaved in a substantially uniform manner among target columns which form uniform-sized column groups between periodic arrangements of clue columns and synchronizing columns.

Encoding multiword information by wordwise interleaving

An encrypting exponentiation modulo M is effected by a modular multiplication X*YmodM, where M is a temporally steady but instance-wise non-uniform modulus. The method involves an iterative series of steps. Each step executes one or two first multiplications to produce a first result, and a trim-down reduction of the size of the first result by one or more second multiplications to produce a second result. The method furthermore takes a distinctive measure for keeping the final result of each step below a predetermined multiplicity of the modulus. In particular, the method postpones substantially any subtraction of the modulus as pertaining to the measure to a terminal phase of the modular exponentiation. This is possible through choosing in an appropriate manner one or more parameters figuring in the method. This further maintains overall temporal performance.

Method and device for executing a decrypting mechanism through calculating a standardized modular exponentiation for thwarting timing attacks

A stream of channel bits, of a signal relating to a binary channel, is decoded into a stream of source bits, of a signal relating to a binary source. This binary channel includes a main channel and a secondary channel. This secondary channel is embedded in the main channel. Errors in the stream of secondary channel bits are corrected using a stream of corrected main channel bits. This stream of corrected main channel bits is reconstructed from a stream of corrected source bits. The secondary channel can be embedded in the main channel in different manners, e.g. via multi-level coding or via merging-bit coding.

Method of decoding a stream of channel bits of a signal relating to a binary channel signal into a steam of source bits of a signal relating to a binary source signal

Growing community of inventors

Eindhoven, Netherlands

Marten Erik Van Dijk