Abstract:
Some embodiments provide a method for performing an iterative block cipher. Line rotations and column rotations are combined to have a diversity of representations of the AES state. These protections can be performed either in static mode where the rotations are directly included in the code and the tables or in dynamic mode where the rotations are chosen randomly at execution time, depending on some entropic context variables. The two modes can also be advantageously combined together.
Abstract:
The disclosed hash and message padding functions are based on the permutation composition problem. To compute a hash of a message using permutation composition based hashing, the message is split into equal size blocks. For each block, a permutation composition value is computed. The block permutation composition values are then combined through composition to generate an overall permutation composition value. The hash of the message is then based on the overall permutation composition value. To pad a message using permutation composition based padding, the message is split into equal size blocks. For each block, a permutation composition value is computed and the permutation composition value is added to the block. The padded blocks are then recombined to generate the padded message.
Abstract:
Some embodiments provide a method for performing a block cryptographic operation that includes a plurality of rounds. The method receives a message that includes several blocks. The method selects a set of the blocks. The set has a particular number of blocks. The method applies a cryptographic operation to the selected set of blocks. A particular round of the cryptographic operation for a first block in the set is performed after a later round than the particular round for a second block in the set, while a different particular round for the first block is performed before an earlier round than the different particular round for the second block. In some embodiments, at least two rounds for the first block are performed one after the other without any intervening rounds for any other blocks in the set.
Abstract:
Various embodiments of a computer-implemented method of information security using block cipher column rotations are described. The cipher state column rotations provide resistance to white box side channel memory correlation attacks designed to reverse-engineer a symmetric cipher key associated with the information security system. The column rotation operations can be performed on the cipher state of a block cipher, and then removed from the result, to provide obfuscation of the data when in memory, while not impacting the resulting output of the cipher or decipher operation. The method additionally includes performing a first rotation of an iteration specific cipher subkey according to the first rotation index, performing an iteration of the block cipher operations on the cipher state matrix, and rotating the columns of the cipher state matrix according to an inverse of the first rotation index.
Abstract:
In a first computer (digital) data obfuscation process, data which is conventionally arranged in a data structure called an array (e.g., a table) and conventionally stored in computer or computer device memory is obfuscated (masked) by logically or mathematically combining the data, entry-by-entry, with a masking value which is computed as a logical or mathematical function of the entry itself or its index in the array, modulo a security value. The complementary unmasking value is a pointer to the entry's address in the table modulo the security value. In a second computer (digital) data obfuscation process, the addresses (location designations) in memory of a data array are themselves obfuscated (masked) by partitioning the array into blocks of entries and shuffling the order of the data entries in each block by a predetermined algorithm, resulting in a shuffled array also differing from the original array in terms of its size (the total number of entries).
Abstract:
Systems and methods are described for rate-limiting a message-sending client interacting with a message service based on dynamically calculated risk assessments of the probability that the client is, or is not, a sender of a spam messages. The message service sends a proof of work problem to a sending client device with a difficulty level that is related to a risk assessment that the client is a sender of spam messages. The message system limits the rate at which a known or suspected spammer can send messages by giving the known or suspected spammer client harder proof of work problems to solve, while minimizing the burden on normal users of the message system by given them easier proof of work problems to solve that can typically be solved by the client within the time that it takes to type a message.
Abstract:
Some embodiments provide a method for performing an iterative block cipher. Line rotations and column rotations are combined to have a diversity of representations of the AES state. These protections can be performed either in static mode where the rotations are directly included in the code and the tables or in dynamic mode where the rotations are chosen randomly at execution time, depending on some entropic context variables. The two modes can also be advantageously combined together.
Abstract:
Some embodiments provide a method for performing a cryptographic process. The method receives first and second cipher keys. The method generates a set of subkeys corresponding to each of the first and second cipher keys. The set of subkeys for the first cipher key is dependent on the first cipher key and the second cipher key. The method performs the cryptographic process by using the generated sets of subkeys.
Abstract:
In the fields of data security and system reliability and qualification, this disclosure is of a method, system and apparatus for verifying or authenticating a device to a host using a zero-knowledge based authentication technique which includes a keyed message authentication code such as an HMAC or keyed cipher function and which operates on secret information shared between the host and the device. This is useful both for security purposes and also to make sure that a device such as a computer peripheral or accessory or component is qualified to be interoperable with the host.
Abstract:
A device implementing a system for authenticating an identity document includes at least one processor configured to receive, from a service provider, a request associated with verifying an integrity of an identity document, and capture, responsive to receiving the request, image data of the identity document. The at least one processor is further configured to generate a representation based on the image data, the representation comprising form factor data of the identity document, and compare the representation with a prior representation of the identity document, the prior representation comprising prior form factor data of the identity document. The at least one processor is further configured to provide, to the service provider, a response to the request based on comparing the representation with the prior representation.