Abstract: A device receives a password from a user, obtains a public key for a cryptographic algorithm for the device, obtains a password verifier by applying a one-way function to a combination of a unique identifier, the password and the public key, generates the certificate comprising the unique identifier, the public key and the password verifier, signs the certificate using a private key corresponding to the public key thereby obtaining a self-signed certificate, and outputs the self-signed certificate. Also provided is the device.

Abstract: A device receives a password from a user, obtains a public key for a cryptographic algorithm for the device, obtains a password verifier by applying a one-way function to a combination of a unique identifier, the password and the public key, generates the certificate comprising the unique identifier, the public key and the password verifier, signs the certificate using a private key corresponding to the public key thereby obtaining a self-signed certificate, and outputs the self-signed certificate. Also provided is the device.

Abstract: A cryptographic hash value is computed in a hardware processing unit of an apparatus. The cryptographic hash value is computed iteratively processing blocks of data in a predetermined order by, for each block: obtaining at least one intermediate value for the block by applying a function to the block, computing a value of a weight function, and updating at least one hash variable with a corresponding intermediate value only if the value of a weight function is equal to at least one predetermined value. The processing unit then generates the cryptographic hash value from the at least one hash variable.

Abstract: A device downloads and installs an APK file for the application, during which the code is modified. A checksum for the modified code is sent to a trusted entity that checks that the received checksum matches a stored checksum for the application. If so, the received checksum is signed and returned to the device where it is stored. The device can then check the integrity of the modified code by calculating a checksum for the modified code that is compared to the signed checksum. The solution is particularly suitable for devices using the Android OS since the DEX during installation is optimized to an ODEX for which there is no certified checksum.

Abstract: During execution of a modified application that has been obtained by modification of an unmodified application a device determines that code corresponding to the unmodified application also corresponds to the modified application, generates a checksum for the code corresponding to the unmodified application that is compared with a stored checksum for the unmodified application to determine whether these match, and determines that the integrity of the modified application has been successfully verified in case the modified application corresponds to the code corresponding to the unmodified application and in case the checksum for the code corresponding to the unmodified application matches the stored checksum for the unmodified application. The solution is particularly suitable for devices using the Android OS since the DEX during installation is optimized to an ODEX or OAT compiled to ELF files for which there is no certified checksum.

Abstract: During execution of modified code, a device generates a checksum for the modified code, and checks whether the generated checksum matches one of a plurality of stored possible checksums for the modified code, each possible checksum corresponding to a possible code obtained by modification of an original code that was modified to obtain the modified code. In case of a match, the device verifies a signature on the plurality of stored possible checksums, and, if successfully verified, verifies the validity of a certificate for the signing key. The solution is particularly suitable for devices using the Android OS since the DEX during installation is optimized to an ODEX or OAT complied to ELF files for which there is no certified checksum.

Abstract: A device receives an APK file for the application, during which the code is modified. A checksum for the modified code is generated and signed using a signing key of a trusted entity in the OS of the device. The signed checksum and a certificate for the signing key are stored in reserved spaces in memory. The modified application may then be executed during which an integrity verification module in the library of the application can verify the integrity of the modified application. The solution is particularly suitable for devices using the Android OS since the DEX during installation is optimized to an ODEX or compiled to ELF for which there is no signature.

Abstract: A cryptographic hash value is computed in a hardware processing unit of an apparatus. The cryptographic hash value is computed iteratively processing blocks of data in a predetermined order by, for each block: obtaining at least one intermediate value for the block by applying a function to the block, computing a value of a weight function, and updating at least one hash variable with a corresponding intermediate value only if the value of a weight function is equal to at least one predetermined value. The processing unit then generates the cryptographic hash value from the at least one hash variable.

Abstract: A cryptographic device performs modular addition between a first integer value x and a second integer value y in a processor by: obtaining a first masked input {circumflex over (x)}, a second masked input ?, a first mask rx and a second mask ry, the first masked input {circumflex over (x)} resulting from the first integer value x masked by the first mask rx and the second masked input ? resulting from the second integer value y masked by the second mask ry; computing a first iteration masked carry value ?1, using the first masked input {circumflex over (x)}, the second masked input ?, the first mask rx, the second mask ry and a carry mask value ?; recursively updating the masked carry value ?i to obtain a final masked carry value ?k?1, wherein the masked carry value is updated using the first masked input {circumflex over (x)}, the second masked input ?, the first mask rx, the second mask ry, and the carry mask value ?; combining the first masked input {circumflex over (x)} and the second masked input ? and t

Abstract: A method for distributing content in a content distribution system is disclosed which comprises the steps of: encrypting at a Content Packager a content using a content encryption key to generate an encrypted content; sending the content encryption key to a Licensing Authority; receiving from the Licensing Authority a distribution key containing an encryption of the content decryption key (Kc) for a given set of authorized devices; creating a secure link between the content encryption key (Kc) and the content protected by this content encryption key using a signature of the content; and distributing the encrypted content together with the signature of the content. A method for receiving content distributed according to the above-mentioned method in a device able to play back the content is also disclosed where the content signature is checked before any play back of the content.

Abstract: A method for secured entry of personal data is disclosed. This method comprises for each item of personal data a first step of presentation of a virtual keyboard comprising keys and a first cursor, followed by a step of selection of a key corresponding to the item of personal data wherein the virtual keyboard also comprises at least one dummy cursor and wherein the position on the virtual keyboard of the at least one dummy cursor depends on the position of the first cursor. A device for secured entry of personal data configured to implement the method is further disclosed.

Abstract: A method for discovering emulated clients. A verifier sends a cryptographic challenge C to a client and preferably starts a timer. The client uses a deterministic key search algorithm to find the correct key and returns the result as a number of tries needed. The verifier then stops the timer if this was started and verifies that the result is correct and preferably that the response was timely. Also provided is a verifier.

Abstract: There are times when a first user may wish to distribute an excerpt of a protected digital content to a second user, for example for criticism. The protected digital content is divided into a plurality of parts, each part being encrypted using a control word specific for the part, wherein each control word can be generated from a master control word for the protected digital content. A device belonging to the first user selects the parts of the excerpt; generates the control words for the selected parts from the master control word; generates a license for the selected parts, the license comprising the control words for the selected parts; and transmits the selected parts and the license to the receiver of the second user. Also provided is the device of the first user.

Abstract: A device receives a password from a user, obtains a public key for a cryptographic algorithm for the device, obtains a password verifier by applying a one-way function to a combination of a unique identifier, the password and the public key, generates the certificate comprising the unique identifier, the public key and the password verifier, signs the certificate using a private key corresponding to the public key thereby obtaining a self-signed certificate, and outputs the self-signed certificate. Also provided is the device.

Abstract: A cryptographic device performs modular addition between a first integer value x and a second integer value y in a processor by: obtaining a first masked input {circumflex over (x)}, a second masked input ?, a first mask rx and a second mask ry, the first masked input {circumflex over (x)} resulting from the first integer value x masked by the first mask rx and the second masked input ? resulting from the second integer value y masked by the second mask ry; computing a first iteration masked carry value ?1, using the first masked input {circumflex over (x)}, the second masked input ?, the first mask rx, the second mask ry and a carry mask value ?; recursively updating the masked carry value ?i to obtain a final masked carry value ?k?1, wherein the masked carry value is updated using the first masked input {circumflex over (x)}, the second masked input ?, the first mask rx, the second mask ry, and the carry mask value ?; combining the first masked input {circumflex over (x)} and the second masked input ? and t

Abstract: Collaborative execution by a first device and a second device of a software application comprising at least one encrypted instruction. The first device obtains a first encrypted instruction; generates a session key; encrypts the first encrypted instruction; encrypts the session key using a symmetric algorithm and a first key; and transfers the encrypted first encrypted instruction and the encrypted session key to the second device. The second device decrypts the encrypted session key using the first key; decrypts the encrypted first encrypted instruction to obtain the first encrypted instruction; decrypts the first encrypted instruction using a third key to obtain an instruction; encrypts the instruction using the symmetric encryption algorithm and the session key to obtain a second encrypted instruction; and transfers the second encrypted instruction to the first device. The first device decrypts the second encrypted instruction using the session key to obtain the instruction; and executes the instruction.

Abstract: A method for performing a m-ary right-to-left exponentiation using a base x, a secret exponent d and a modulus N, wherein m is a power of 2.

Abstract: A method of generating a segment key KSmt from a given basic key KmT and a given modification key K?MT 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?m and T?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?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?m)+(T?t). This result is XOR-ed with the target basic key to obtain the segment key KSmtAlso provided is a device.

Abstract: A method for secured entry of personal data is disclosed. This method comprises for each item of personal data a first step of presentation of a virtual keyboard comprising keys and a first cursor, followed by a step of selection of a key corresponding to the item of personal data wherein the virtual keyboard also comprises at least one dummy cursor and wherein the position on the virtual keyboard of the at least one dummy cursor depends on the position of the first cursor. A device for secured entry of personal data configured to implement the method is further disclosed.

Abstract: A method of encrypting compiled computer code instructions to be decrypted instruction by instruction during execution. The computer code instructions are encrypted using a chaining mode so that an encrypted instruction depends on the values of the instruction, the value of the preceding instruction and a pseudo-random number. As it may happen that the instruction can be arrived at from more than one preceding instruction, at least one of the preceding instructions is associated with a random number compensator for use during decryption of the encrypted instruction, so that the decryption of the encrypted instruction yields the same result regardless of which the preceding instruction was. Also provided are an encryption device, a decryption device and method, and a digital support medium storing encrypted compiled computer code instructions.