XOR ASM

An example of amd64 (x86-64) assembly language code on Linux to encrypt a file using a simple xor algorithm.

I originally coded this program for friends who were comparing the speed of executing a simple algorithm in different programming languages. And I decided to bring out the big guns.

Build instructions

You can use these parameters when assembling:

• -dUNROLL_LOOP // Unrolls the loop to increase the execution speed by increasing the binary size.
• -dBUFFER_SIZE=2048 // Reading buffer size. Be aware of the stack size limit.
• -dXOR_KEY=0xFF // One-byte xor key value.

And optionally, one of the options for SIMD instructions:

• -dXOR_SSE2
• -dXOR_AVX2
• -dXOR_AVX512

Building

nasm -f elf64 xor.asm
ld xor.o -s -o xor

License

The source code is published under GPLv3, the license is available here.