[Sharif University CTF Quals 2013] one Line encoder For Specialist pRogrammer (crypto200)
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>>> len(key) 9 >>> set(key) set(['1', '0']) >>> >>> >>> suctf_enc = lambda text, key: reduce(lambda x, y: (x[0] + str(int(y) ^ int(x[1][0])), x[1][1:] + str(int(x[1][4]) ^ int(x[1][0]))), ''.join(map(lambda x: bin(ord(x))[2:].rjust(8, '0'), text)), ('', key))[0] >>> >>> >>> suctf_enc(text, key) '10100101011010000001001011101110010000001000010111000001101000110010110110001010100000001110010001111011010101100110101001111111001110010110101111111011100000001011110101111100010101001111100011011111111011000110100010000011000110100000010111101100010110000000110010101001100001101110110111101101001001001101010100001101100101001000111110110110001111001000011000011000110000100100001001001100011101101111111101010101000010101110001100010011000111010110010101101011111100111000010100100001000001101010111111011101101110000111111000000000011111010011011010100010000101111100100111000001111001111010101001101110110110011001111101110011100111101100001101101011010110111011111011001100001111001000101101010100000000010011001001110000101100011101011010101100001011101001110010010110111011011011101001110110010000000010100100101000101001001000100110101110111111101111100010101001101110111110010010101011001001100000000101110001001110100010011010100110100001001010111011101111011000111100111010000011111001111010110010110011001000000100010001111001101111100101000110011111' >>> >>> # flag = md5(key) |
Có thể để ý ngay những chữ viết hoa trong tên bài, nó là LFSR, nhưng kệ Nội dung chính Ở bài này, chúng ta có một hàm encode, đầu vào là...
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