Abstract: Disclosed herein are systems, methods, and computer-readable storage media for obfuscating using inlined functions. A system configured to practice the method receives a program listing including annotated functions for obfuscation, identifies an annotated function called more than once in the program listing, and creates an inline control flow structure in the program listing for the identified annotated function, the control flow structure being computationally equivalent to inlining the identified annotated function into the program listing for each occurrence of the identified annotated function. The program listing can include tiers of annotated functions. The system can identify annotated functions called more than once based on an optionally generated callgraph. The system can create inline control flow structures in the program listing in order of annotation importance. The system can identify how many times each annotated function is called in the program listing.

Abstract: In the field of computer software, obfuscation techniques for enhancing software security are applied to compiled (object) software code. The obfuscation results here in different versions (instances) of the obfuscated code being provided to different installations (recipient computing devices). The complementary code execution uses a boot loader or boot installer-type program at each installation which contains the requisite logic. Typically, the obfuscation results in a different instance of the obfuscated code for each intended installation (recipient) but each instance being semantically equivalent to the others. This is accomplished in one version by generating a random value or other parameter during the obfuscation process, and using the value to select a particular version of the obfuscating process, and then communicating the value along with boot loader or installer program software.

Abstract: A branch auditing system can be automatically injected into a computer program, in one embodiment, in response to a programming call provided in source code by a programmer who has selected a particular branch, in a set of possible branches, for auditing. The branch auditing system can record, in an obfuscated data structure, a path taken at the particular branch and the parameters associated with the branch and later an auditor can determine whether the path taken was valid, and if the path taken was invalid, operations can be performed to protect the program, system and/or user.

Abstract: Methods, media and systems that obfuscate control flow in software programs. The obfuscation can impede or prevent static flow analysis of a software program's control flow. In one embodiment, a method, performed by a data processing system, identifies each branch point in a set of branch points in a first version of software and replaces, in each branch point in the set, a representation of a target of the branch point with a computed value that depends upon at least one prior computed value in a stream of instructions in the first version of software. Other embodiments are also described.

Abstract: Disclosed herein are systems, methods, and non-transitory computer-readable storage media for executing encrypted computer code. A system configured to practice the method receives a request to execute encrypted computer code. In response to the request, the system identifies a portion of the encrypted computer code for execution and decrypts the portion to yield decrypted computer code. Then the system stores the decrypted computer code in a pool of memory and executes the decrypted computer code from the pool of memory. The system can store the decrypted computer code in the pool of memory based on a randomization algorithm so that identical executions of the encrypted computer code result in selections of different available memory locations within the pool of memory. Related portions can be stored non-consecutively in the pool of memory. The pool of memory can store different portions of decrypted computer code over time.

Abstract: A method and an apparatus that provide rewriting code to dynamically mask program data statically embedded in a first code are described. The program data can be used in multiple instructions in the first code. A code location (e.g. an optimal code location) in the first code can be determined for injecting the rewriting code. The code location may be included in two or more execution paths of first code. Each execution path can have at least one of the instructions using the program data. A second code may be generated based on the first code inserted with the rewriting code at the optimal code location. The second code can include instructions using the program data dynamically masked by the rewriting code. When executed by a processor, the first code and the second code can generate identical results.

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: 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: Techniques, methods, systems, and computer-readable media for allocating and managing dynamically obfuscated heap memory allocations are described. In one embodiment a memory manager in a data processing system contains an addressor, to determine a first address of a program object in a first memory address space, and one or more encoders, to abstract memory access to the program object using the first address such that layout of the object data in the first address space differs from the layout of the object in a second address space. In one embodiment, a runtime system modifies object code of an executable file to include encoder routines to abstract memory accesses to data in an obfuscated heap. In one embodiment, a compiler system using an intermediate representation of a high level program generates an intermediate representation of a high level program capable of performing memory writes and memory reads using obfuscation encoder routines.

Abstract: In one embodiment, a system wide static global stack pool in a contiguous range of random access memory is generated, a block of memory in the system global pool is assigned to a thread of a running process, and the thread stores local variable information in static global stack pool, such that the local variable is hidden from a stack frame back-trace. In one embodiment, a dynamically allocated data structure in system heap memory is generated, the data structure is locked to ensure atomic access, a block of memory in the data structure is assigned to a thread of a process, the data structure is unlocked, and the thread stores local variable information in static global stack pool, such that the local variable is hidden from a stack frame back-trace.

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: Disclosed herein are systems, methods, and non-transitory computer-readable storage media for obfuscating a computer program. A system configured to practice the method identifies a set of executable instructions at a first location in an instruction section of the computer program and identifies a second location in a data section of the computer program. Then the system moves the set of executable instructions to the second location and patches references in the computer program to the set of executable instructions to point to the second location. The instruction section of the computer program can be labeled as _TEXT,_text and the data section of the computer program is labeled as _DATA,_data. The set of executable instructions can include one or more non-branching instructions optionally followed by a branching instruction. The placement of the first and second locations can be based on features of a target computing architecture, such as cache size.

Abstract: Disclosed herein are systems, methods, and computer readable-media for obfuscating code. The method includes extracting a conditional statement from a computer program, creating a function equivalent to the conditional statement, creating a pointer that points to the function, storing the pointer in an array of pointers, replacing the conditional statement with a call to the function using the pointer at an index in the array, and during runtime of the computer program, dynamically calculating the index corresponding to the pointer in the array. In one aspect, a subset of instructions is extracted from a path associated with the conditional statement and the subset of instructions is placed in the function to evaluate the conditional statement. In another aspect, the conditional statement is replaced with a call to a select function that (1) calculates the index into the array, (2) retrieves the function pointer from the array using the index, and (3) calls the function using the function pointer.

Abstract: Methods, media and systems that use an encoded opaque pointer in an API between a client process and a library process. An encoded opaque pointer, in one embodiment, can be received by the library process from the client process, and the library process can decode the opaque pointer to obtain an address in memory containing a data structure pointed to by the opaque pointer. The library process can operate on the data structure to create a revised or processed data structure, stored in the same or different address in heap memory or stack memory, and the library process can encode and return a new opaque pointer, for the processed data structure, to the client process.

Abstract: Methods, media and systems that obfuscate control flow in software programs. The obfuscation can impede or prevent static flow analysis of a software program's control flow. In one embodiment, a method, performed by a data processing system, identifies each branch point in a set of branch points in a first version of software and replaces, in each branch point in the set, a representation of a target of the branch point with a computed value that depends upon at least one prior computed value in a stream of instructions in the first version of software. Other embodiments are also described.

Abstract: Disclosed herein are systems, methods, and computer readable-media for obfuscating array contents in a first array, the method comprising dividing the first array into a plurality of secondary arrays having a combined total size equal to or greater than the first array, expanding each respective array in the plurality of the secondary arrays by a respective multiple M to generate a plurality of expanded arrays, and arranging data elements within each of the plurality of expanded arrays such that a data element located at an index I in a respective secondary array is located at an index I*M, wherein M is the respective multiple M in an associated expanded array, wherein data in the first array is obfuscated in the plurality of expanded arrays. One aspect further splits one or more of the secondary arrays by dividing individual data elements in a plurality of sub-arrays. The split sub-arrays may contain more data elements than the respective secondary array.

Abstract: Disclosed herein are systems, methods, and non-transitory computer-readable storage media for obfuscating data using instructions as a source of pseudorandom values. Obfuscation is performed by receiving instructions and data and compiling the instructions and the data into an executable file having a text section and a data section. The text section can include instructions and the data section can include data segments. The system obfuscates the data section iteratively by generating a hash of an address for a respective data segment, and based on the hash, identifying a corresponding address in the text section that includes at least one instruction. The system retrieves a mask key from the corresponding address and applies the mask key to the respective data segment, yielding a masked data segment. In one embodiment, integrity verification of obfuscated data is performed without exposing the data in an unprotected state by utilizing multiple mask keys.

Abstract: Disclosed herein are systems, methods, and computer readable-media for obfuscating code through conditional expansion obfuscation. The method includes identifying a conditional expression in a computer program, identifying a sequence of conditional expressions that is semantically equivalent to the conditional expression, and replacing the conditional expression with the semantically equivalent sequence of conditional expressions. One option replaces each like conditional expression in the computer program with a diverse set of sequences of semantically equivalent conditional expressions. A second option rearranges computer instructions that are to be processed after the sequence of conditional expression is evaluated so that a portion of the instructions is performed before the entire sequence of conditional expressions is evaluated. A third option performs conditional expansion obfuscation of a conditional statement in combination with branch extraction obfuscation.

Abstract: Disclosed herein are systems, computer-implemented methods, and computer-readable storage media for obfuscating a function call. The method receives a computer program having an annotated function and determines prolog instructions for setting up a stack frame of the annotated function and epilog instructions for tearing down the stack frame. The method places a first portion of the prolog instructions in the computer program preceding a jump to the annotated function and a second portion of the prolog instructions at a beginning of the annotated function. The method places a first portion of the epilog instructions at an end of the annotated function and a second portion of the epilog instructions in the computer program after the jump. Executing the first and second portions of the prolog instructions together sets up the stack frame. Executing the first and the second portions of the epilog instructions together tears down the stack frame.