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: 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: 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 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 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: 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 non-transitory computer-readable storage media for binary layout randomization. A system performs binary layout randomization by loading computer code into memory and identifying a section of the computer code to randomize. A loader remaps the section of computer code to a different location in memory utilizing a remapping algorithm. The loader can shuffle sections of code in place or move sections of code elsewhere. The loader patches relative addresses to point to the updated locations in memory. After the system patches the addresses, the system executes the computer code from memory. In one embodiment, the system encrypts the computer code prior to loading the computer code into memory. The loader decrypts the encrypted computer code prior to remapping the section of computer code to a different location in memory. Optionally, the loader can decrypt the encrypted computer code after patching relative addresses.

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: This disclosure is directed to measuring hardware-based statistics, such as the number of instructions executed in a specific section of a program during execution, for enforcing software security. The counting can be accomplished through a specific set of instructions, which can either be implemented in hardware or included in the instruction set of a virtual machine. For example, the set of instructions can include atomic instructions of reset, start, stop, get instruction count, and get CPU cycle count. To obtain information on a specific section of code, a software developer can insert start and stop instructions around the desired code section. For each instruction in the identified code block, when the instruction is executed, a counter is incremented. The counter can be stored in a dedicated register. The gathered statistics can be used for a variety of purposes, such as detecting unauthorized code modifications or measuring code performance.

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.