Opdis is a wrapper for the libopcodes disassembler library distributed as part of GNU binutils. It extends the libopcodes library by offering linear and control-flow disassembly algorithms, instruction and operand objects that are suitable for analysis, and a command-line utility to perform disassembly on arbitrary locations in a file. The Opdis project consists of the libopdis library and the opdis command-line utility. There is a Ruby gem providing access to libopdis, and a supporting gem providing access to libbfd.
The Obcode (obfuscated code) library allows the programmer to perform arithmetic (e.g. data encryption and serial code generation) over abstract, parameterizable, and obfuscated data types using special high-level operators. The resulting low-level binary code doesn't reveal any real data directly and is if not very difficult, then at least very boring to reverse engineer and trace.
Chump is a table-driven assembler and dissembler with a very fast new architecture input format. Both the assembler and disassembler are created using a single description. It comes with descriptions for ARM, MIPS, Stump, and 6809. It is intended for use as a library compiled with other programs to allow line assembly and disassembly.
joeq is a Java 2 (JDK 1.3 and 1.4) compatible virtual machine. It is unique in that it is entirely implemented in Java, leading to greater reliability, portability, maintainability, and efficiency. It is also language-independent, so code from any supported language can be seamlessly compiled, linked, and executed dynamically.