defget_base64_diff_value(s1, s2): base64chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/' res = 0 for i in xrange(len(s2)): if s1[i] != s2[i]: returnabs(base64chars.index(s1[i]) - base64chars.index(s2[i])) return res
defsolve_stego(): withopen('1.txt', 'rb') as f: file_lines = f.readlines() bin_str = '' for line in file_lines: steg_line = line.replace('\n', '') norm_line = line.replace('\n', '').decode('base64').encode('base64').replace('\n', '') diff = get_base64_diff_value(steg_line, norm_line) print diff pads_num = steg_line.count('=') if diff: bin_str += bin(diff)[2:].zfill(pads_num * 2) else: bin_str += '0' * pads_num * 2 print goflag(bin_str)
defgoflag(bin_str): res_str = '' for i in xrange(0, len(bin_str), 8): res_str += chr(int(bin_str[i:i + 8], 2)) return res_str
if __name__ == '__main__': solve_stego()
直接输入base64隐写后的内容即可
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