摘要:
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.
摘要:
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.
摘要:
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. Calls can be routed through a select function before the function pointer is used to call the function evaluating the conditional statement. Each step in the method can be applied to source code of the computer program, an intermediate representation of the computer program, and assembly code of the computer program.
摘要:
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. The principles herein may be applied to single dimensional or multi-dimensional arrays. The obfuscated array contents may be accessed via an index to the first array which is translated to retrieve data elements stored in the plurality of expanded arrays.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.