蓝帽2023半决

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# PREFACE: 赛中总觉得是该用 z3 写，或者 angr 跑，但是死活出不来，结果发现就是一个矩阵乘法

先给个程序流程，比较简单的

image-20230919191052104

image-20230919191107056

就没了，就结束了…

exp

import numpy as np
A = [0xfe, 0xb, 0x1d, 0xf6, 0x83, 0xff, 0xe0, 0xb8, 0xdd, 0xb0, 0xc5, 0xde, 0xf6, 0x14, 0x9f, 0xdd, 0xd9, 0x7, 0x2d, 0x6b, 0x19, 0xca, 0x73, 0xfd, 0x87, 0x72, 0x24, 0x4, 0x49, 0x7e, 0xa9, 0xce, 0x91, 0xbe, 0x41, 0x18, 0x60, 0x3f, 0x2b, 0x63, 0x1c, 0xd2, 0x90, 0xe9, 0x8e, 0xba, 0x1e, 0xf3, 0x41, 0xad,
     0x2c, 0x3, 0x69, 0xda, 0x10, 0xfd, 0xfd, 0xe7, 0x6, 0x36, 0xd6, 0x2, 0x59, 0x18, 0xcc, 0x50, 0x87, 0xaf, 0xfb, 0x18, 0x44, 0x7f, 0xad, 0xf8, 0x2c, 0x67, 0x1d, 0x22, 0x84, 0xac, 0xe, 0x23, 0xdc, 0xe6, 0xbb, 0xd2, 0xb8, 0x4a, 0xbc, 0xde, 0x50, 0x9c, 0x1c, 0x1e, 0x86, 0x3a, 0x2d, 0xdd, 0xc3, 0x3]
B = [0x1c633, 0x1df94, 0x20ebf, 0x2ba40, 0x1e884, 0x260d1, 0x1f9b1, 0x1ea1a, 0x1eeaa, 0x1dfb2, 0x1c1d0, 0x1eef2, 0x216e1, 0x2be00, 0x1fb5e, 0x25d74, 0x1f000, 0x202d6, 0x20002, 0x1ddfe, 0x1c017, 0x1f08c, 0x227f6, 0x2c7ba, 0x201ae, 0x27fbf, 0x20e21, 0x1ff5c, 0x1fd62, 0x1e948, 0x1be6e, 0x1f4d7, 0x22c8d, 0x2c353, 0x1f8db, 0x26e1d, 0x1ff61, 0x1ea0f, 0x1f0d6, 0x1eda8, 0x1ad7d, 0x18218, 0x1ccd4, 0x239b6, 0x1ac4c, 0x20d7c, 0x1d967, 0x1a4f4, 0x1cad8, 0x196ae,
     0x1831b, 0x17e45, 0x1d0cf, 0x23edf, 0x181ae, 0x21760, 0x1d3b4, 0x175d6, 0x17d3a, 0x1994f, 0x1189d, 0x14ccf, 0x1568e, 0x17eeb, 0x1327e, 0x16a45, 0x12921, 0x11ff0, 0x13643, 0x11729, 0x15191, 0x17d17, 0x17262, 0x1a863, 0x17010, 0x17b10, 0x14f9c, 0x143e8, 0x15e9b, 0x1242c, 0xf68c, 0x1192a, 0x150ad, 0x1b1a0, 0x14c60, 0x182ab, 0x13f4b, 0x141a6, 0x15aa3, 0x135c9, 0x1d86f, 0x1e8fa, 0x2158d, 0x2bdac, 0x20e4f, 0x27ee6, 0x213b9, 0x20e86, 0x211ff, 0x1e1ef]
A_Mat = []
B_Mat = []
for i in range(0, 100, 10):
    tmp = A[i:i+10]
    A_Mat.append(tmp)
    tmp = B[i:i+10]
    B_Mat.append(tmp)
A_Mat = np.mat(A_Mat)
B_Mat = np.mat(B_Mat)
X_Mat = np.dot(B_Mat, np.linalg.inv(A_Mat))
for i in range(len(X_Mat)):
    tmp = X_Mat[i].tolist()[0]
    for j in range(len(tmp)):
        print(chr(round(tmp[j])), end="")
# there_are_a_lot_useless_information_but_oh.o0O_flag{8f9c6cf7-f362-4a4e-ace2-a34d90939589}_you_get_it