In computer programming, machine code is computer code consisting of machine language instructions, which are used to control a computer's central processing unit (CPU). Although decimal computers were once common, the contemporary marketplace is dominated by binary computers; for those computers, machine code is "the binary representation of a computer program which is actually read and interpreted by the computer. A program in machine code consists of a sequence of machine instructions ."
A disassembler is a computer program that translates machine language into assembly language—the inverse operation to that of an assembler. Disassembly, the output of a disassembler, is often formatted for human-readability rather than suitability for input to an assembler, making it principally a reverse-engineering tool. Common uses of disassemblers include analyzing high-level programing language compilers output and their optimizations, recovering source code of a program whose original source was lost, malware analysis, modifying software, and software cracking.
In computing, cross-platform software is computer software that is designed to work in several computing platforms. Some cross-platform software requires a separate build for each platform, but some can be directly run on any platform without special preparation, being written in an interpreted language or compiled to portable bytecode for which the interpreters or run-time packages are common or standard components of all supported platforms.
Bytecode is a form of instruction set designed for efficient execution by a software interpreter. Unlike human-readable source code, bytecodes are compact numeric codes, constants, and references that encode the result of compiler parsing and performing semantic analysis of things like type, scope, and nesting depths of program objects.
In computer architecture, 64-bit integers, memory addresses, or other data units are those that are 64 bits wide. Also, 64-bit central processing units (CPU) and arithmetic logic units (ALU) are those that are based on processor registers, address buses, or data buses of that size. A computer that uses such a processor is a 64-bit computer.
In computer science, dynamic recompilation is a feature of some emulators and virtual machines, where the system may recompile some part of a program during execution. By compiling during execution, the system can tailor the generated code to reflect the program's run-time environment, and potentially produce more efficient code by exploiting information that is not available to a traditional static compiler.
LLVM is a set of compiler and toolchain technologies that can be used to develop a frontend for any programming language and a backend for any instruction set architecture. LLVM is designed around a language-independent intermediate representation (IR) that serves as a portable, high-level assembly language that can be optimized with a variety of transformations over multiple passes. The name LLVM originally stood for Low Level Virtual Machine, though the project has expanded and the name is no longer officially an initialism.
The Interactive Disassembler (IDA) is a disassembler for computer software which generates assembly language source code from machine-executable code. It supports a variety of executable formats for different processors and operating systems. It can also be used as a debugger for Windows PE, Mac OS X Mach-O, and Linux ELF executables. A decompiler plug-in, which generates a high level, C source code-like representation of the analysed program, is available at extra cost.
CMUCL is a free Common Lisp implementation, originally developed at Carnegie Mellon University.
QEMU is a free and open-source emulator. It emulates a computer's processor through dynamic binary translation and provides a set of different hardware and device models for the machine, enabling it to run a variety of guest operating systems. It can interoperate with Kernel-based Virtual Machine (KVM) to run virtual machines at near-native speed. QEMU can also do emulation for user-level processes, allowing applications compiled for one architecture to run on another.
Ghidra is a free and open source reverse engineering tool developed by the National Security Agency (NSA) of the United States. The binaries were released at RSA Conference in March 2019; the sources were published one month later on GitHub. Ghidra is seen by many security researchers as a competitor to IDA Pro. The software is written in Java using the Swing framework for the GUI. The decompiler component is written in C++, and is therefore usable in a stand-alone form.
Dalvik is a discontinued process virtual machine (VM) in the Android operating system that executes applications written for Android. Dalvik was an integral part of the Android software stack in the Android versions 4.4 "KitKat" and earlier, which were commonly used on mobile devices such as mobile phones and tablet computers, and more in some devices such as smart TVs and wearables. Dalvik is open-source software, originally written by Dan Bornstein, who named it after the fishing village of Dalvík in Eyjafjörður, Iceland.
A decompiler is a computer program that translates an executable file to high-level source code. It does therefore the opposite of a typical compiler, which translates a high-level language to a low-level language. While disassemblers translate an executable into assembly language, decompilers go a step further and translate the code into a higher level language such as C or Java, requiring more sophisticated techniques. Decompilers are usually unable to perfectly reconstruct the original source code, thus will frequently produce obfuscated code. Nonetheless, they remain an important tool in the reverse engineering of computer software.
Jad is, as of August 2011, an unmaintained decompiler for the Java programming language. Jad provides a command-line user interface to extract source code from class files.
This article compares the application programming interfaces (APIs) and virtual machines (VMs) of the programming language Java and operating system Android.
Java bytecode is the instruction set of the Java virtual machine (JVM), crucial for executing programs written in the Java language and other JVM-compatible languages. Each bytecode operation in the JVM is represented by a single byte, hence the name "bytecode", making it a compact form of instruction. This intermediate form enables Java programs to be platform-independent, as they are compiled not to native machine code but to a universally executable format across different JVM implementations.
Ethereum is a decentralized blockchain with smart contract functionality. Ether is the native cryptocurrency of the platform. Among cryptocurrencies, ether is second only to bitcoin in market capitalization. It is open-source software.
Android Runtime (ART) is an application runtime environment used by the Android operating system. Replacing Dalvik, the process virtual machine originally used by Android, ART performs the translation of the application's bytecode into native instructions that are later executed by the device's runtime environment.
Radare2 is a complete framework for reverse-engineering and analyzing binaries; composed of a set of small utilities that can be used together or independently from the command line. Built around a disassembler for computer software which generates assembly language source code from machine-executable code, it supports a variety of executable formats for different processor architectures and operating systems.
Binary Ninja is a reverse-engineering platform developed by Vector 35 Inc. It can disassemble a binary and display the disassembly in linear or graph views. It performs automated in-depth analysis of the code, generating information that helps to analyze a binary. It lifts the instructions into intermediate languages, and eventually generates the decompiled code.
