re | [RCTF2019]asm

re | [RCTF2019]asm

简单file一下：

推测是risc-v64位，去网上找逆向脚本：
这个反汇编器是可以用的：
https://github.com/riscv/riscv-gnu-toolchain

或者用下面这个idaproc可以打开，但是效果不太好。
https://github.com/bingseclab/ida_riscv

总之就是装第一个工具然后objdump能够查看反汇编(这里参考了官方wp)，exp如下：

data = [0x11,0x76,0xd0,0x1e,0x99,0xb6,0x2c,0x91,0x12,0x45,0xfb,0x2a,0x97,0xc6,0x63,0xb8,0x14,0x7c,0xe1,0x1e,0x83,0xe6,0x45,0xa0,0x19,0x63,0xdd,0x32,0xa4,0xdf,0x71,0x00]
print(len(data))
flag = ""
a = ord('R')
data_len = len(data)
for i in range(data_len):
    flag += chr(a)
    a = a ^ data[i] ^ ((i * 97) % 256)
print(flag)