Abstract: A method and an apparatus for receiving a first source code having a code block to update the first source code with multiple copies of the code block to protect against correlation attacks are described. The code block can perform one or more operations for execution based on the first source code. The operations can be performed via a random one of the copies of the code block. A second source code based on the updated first source code can be generated to be executed by a processor to produce an identical result as the first source code.

Abstract: Disclosed herein are systems, methods, and non-transitory computer-readable storage media for obfuscating branches in computer code. A compiler or a post-compilation tool can obfuscate branches by receiving source code, and compiling the source code to yield computer-executable code. The compiler identifies branches in the computer-executable code, and determines a return address and a destination value for each branch. Then, based on the return address and the destination value for each branch, the compiler constructs a binary tree with nodes and leaf nodes, each node storing a balanced value, and each leaf node storing a destination value. The non-leaf nodes are arranged such that searching the binary tree by return address leads to a corresponding destination value. Then the compiler inserts the binary tree in the computer-executable code and replaces each branch with instructions in the computer-executable code for performing a branching operation based on the binary tree.

Abstract: In the field of computer enabled cryptography, such as a block cipher, the cipher is hardened against an attack by protecting the cipher key, by applying to it a predetermined linear permutation before using one key to encrypt or decrypt a message. This is especially advantageous in a “White Box” environment where an attacker has full access to the cipher algorithm, including the algorithm's internal state during its execution. This method and the associated computing apparatus are useful where the key is derived through a process and so is unknown when the software code embodying the cipher is compiled. This is typically the case where there are many users of the cipher and each has his own key, or where each user session has its own key.

Abstract: Method and apparatus to prevent hacking of encrypted audio or video content during playback. Hackers, using a debugging attachment or other tools, can illicitly access encrypted data in memory in a playback device when the data is decrypted during playback and momentarily stored in digital form. This hacking is defeated here by methodically “poisoning” the encrypted data so that it is no longer playable by a standard decoder. The poisoning involves deliberate alteration of certain bit values. On playback, the player invokes a special secure routine that provides correction of the poisoned bit values, for successful playback.

Abstract: Method and apparatus for obfuscating computer software code, to protect against reverse-engineering of the code. The obfuscation here is of the part of the code that performs a Boolean logic operation such as an exclusive OR on two (or more) data variables. In the obfuscated code, each of the two variables is first modified by applying to it a function which deconstructs the value of each of the variables, and then the exclusive OR operation is replaced by an arithmetic operation such as addition, subtraction, or multiplication, which is performed on the two deconstructed variables. The non-obfuscated result is recovered by applying a third function to the value generated by the arithmetic operation. This obfuscation is typically carried out by suitably annotating (modifying) the original source code.

Abstract: A video on demand system in the context of the Internet, for video rentals. A user accesses an on-line store to rent a video program or movie. The rental is for a limited time (such as 30 days) and within that thirty days, the video program or movie can only be viewed for a 24 hour time window. The time limits are enforced by the on-line store which maintains a database of each rental transaction and allows supply of the needed keys for decrypting the (encrypted) video or movie only if within the time limits.

Abstract: In the data security field, a data protection process embodied in a computer system or computing device or equivalent and which securely descrambles protected (scrambled) data. The process descrambles the data using a dynamic process employing a set of multi-level trees of deterministic functions to generate a descrambling mask value and recover the descrambled message.

Abstract: In the field of cryptography, such as for a computer enabled block cipher, a cipher or other cryptographic process is hardened against an attack by protecting the cipher key or subkeys by using a masking process for these keys. The subkeys are thereby protected by applying to them a mask or set of masks to hide their contents. This is especially advantageous in a “White Box” computing environment where an attacker has full access to the cipher algorithm, including the algorithm's internal state during execution. Further, this method and the associated apparatus are useful where the key is derived through a process and so is unknown when the software code embodying the cipher is compiled. This is typically the case where there are many users of the cipher and each has his own key or where each user session has its own key.

Abstract: In the field of computer software (code) security, it is known to include verification data such as hash values in or associated with the code to allow subsequent detection of tampering by a attacker with the code. This verification technique is used here in a “White Box” cryptographic process by tying the verification data to the content of functional table lookups present in the object (compiled) code, where values in the table lookups are selectively masked (prior to the source code being compiled into the subject code) by being subject to permutation operations.

Abstract: In the field of computer enabled cryptography, such as a keyed block cipher having a plurality of sequenced rounds, the cipher is hardened against attack by a protection process. The protection process uses block lengths that are larger or smaller than and not an integer multiple of those of an associated standard cipher, and without using message padding. This is operative in conjunction with standard block ciphers such as the AES, DES or triple DES ciphers, and also with various block cipher cryptographic modes such as CBC or EBC.

Abstract: A method and associated apparatus for use in a data distribution process to allow an untrusted intermediary to re-encrypt data for transmission from an originator to a message receiver without revealing the data (message) or the cipher to the intermediary. This method uses a composition of two ciphers for re-encrypting the message at the intermediary, without revealing the plain text message or either cipher to the intermediary.

Abstract: In one embodiment, non-transitory computer-readable medium stores instructions for establishing a trusted two-way communications session for account creation for an online store, which include instructions for causing a processor to perform operations comprising retrieving and verifying a signed configuration file from a server, requesting a communication session using the configuration file, receiving a payload of account creation forms from a network client, signing the payload according to the server configuration file, and sending the signed payload containing account creation information to the server. In one embodiment, a computer-implemented method comprises analyzing timestamps for requests for data forms for supplying account creation information for evidence of automated account creation activity and rejecting the request for the locator of the second account creation form if evidence of automated account creation activity is detected.

Abstract: In the field of computer enabled cryptography, such as a keyed block cipher having a plurality of rounds, the cipher is hardened against an attack by a protection process which obscures the round keys using the properties of group field automorphisms and applying masks to the states of the cipher, for encryption or decryption. This is especially advantageous in a “White Box” environment where an attacker has full access to the cipher algorithm, including the algorithm's internal state during its execution. This method and the associated computing apparatus are useful for protection against known attacks on “White Box” ciphers, by eliminating S-box operations, together with improved masking techniques and increasing the cipher's complexity against reverse engineering and key storage attacks.

Abstract: Some embodiments of the invention provide a content-distribution system. In some embodiments, the content-distribution system distributes device-restricted content and device-unrestricted content. Device-restricted content is content that can only be played on devices that the system associates with the particular user. Device-unrestricted content is content that can be played on any device without any restrictions. However, for at least one operation or service other than playback, device-unrestricted content has to be authenticated before this operation or service can be performed on the content. In some embodiments, the system facilitates this authentication by specifying a verification parameter for a piece of device-unrestricted content.

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: First source code of a computer program having a plurality of lines of instructions is received. An obfuscation process is performed on the first source code, including at least two of a shuffling operation, a fertilizing operation, an aggregating operation, and a neutralizing operation. Second source code is generated based on the obfuscation process, where the second source code, when executed by a processor, produces an identical result as the first source code.

Abstract: Disclosed are systems, methods, and non-transitory computer-readable storage media for detecting changes in a source of entropy. A system configured to practice the method generates a cyclic graph based at least in part on the values in the entropy pool. Using the cyclic graph and one or more starting points, the system establishes one or more baseline properties for the cyclic graph. These properties can include the number of steps required to identify a cycle in the graph or the number of steps required to traverse the graph from one or more starting points to a selected end point. The computed properties are then stored for later use. As execution progresses, the system monitors the entropy pool to detect a change by regenerating the cyclic graph and using the stored properties.

Abstract: Disclosed herein are systems, methods, and computer-readable storage media for obfuscating by a common function. A system configured to practice the method identifies a set of functions in source code, generates a transformed set of functions by transforming each function of the set of functions to accept a uniform set of arguments and return a uniform type, and merges the transformed set of functions into a single recursive function. The single recursive function can allocate memory in the heap. The stack can contain a pointer to the allocated memory in the heap. The single recursive function can include instructions for creating and explicitly managing a virtual stack in the heap. The virtual stack can emulate what would happen to the real stack if one of the set of functions was called. The system can further compile the source code including the single recursive function.

Abstract: Method and apparatus for increasing security of a cryptographic algorithm such as deciphering, enciphering, or a digital signature using a block type cipher such as AES implemented for instance in a “whitebox” model with the cipher key either known or unknown at the compilation time. This method is secure for use in entrusted environments, particularly for securing cryptographic keys. The look up tables characteristic of such algorithms are protected against attack here by making all such tables of the same size and indistinguishable, and further by masking the output values of such tables, typically where the tables carry out a permutation function or a logical exclusive OR operation.

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.