反转 RSA 公钥的编码

逆向工程 密码学
2021-06-19 07:33:15

我想弄清楚这个的格式/编码：

00040000a56e4a0e701017589a5187dc7ea841d156f2ec0e36ad52a44dfeb1e61f7ad991d8c51056ffedb162b4c0f283a12a88a394dff526ab7291cbb307ceabfce0b1dfd5cd9508096d5b2b8b6df5d671ef6377c0921cb23c270a70e2598e6ff89d19f105acc2d3f0cb35f29280e1386b6f64c4ef22e1e1f20d0ce8cffb2249bd9a2137000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001000100040000a56e4a0e70101759a5187dc7ea841d156f2ec0e36ad52a44dfeb1e61f7ad991d8c51056ffedb162b4c0f283a12a88a394dff526ab7291cbb307ceabfce0b1dfd5cd9508096d5b2b8b6df5d671ef6377c0921cb23c270a70e2598e6ff89d19f105acc2d3f0cb35f29280e1386b6f64c4ef22e1e1f20d0ce8cffb2249bd9a2137000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000010001 用我自己的公钥复制它。

我看过这个https://crypto.stackexchange.com/questions/41871/how-to-find-the-encoding-of-an-rsa-public-key并且从我所看到的有相似之处，虽然它似乎与那不一样。

1个回答

00040000 看起来像一个代表数据长度的 32 位值。

如果我们用 little-endian 解码它，我们会得到1024：

sage: int.from_bytes(bytes.fromhex('00040000'), 'little')
1024

我假设这给出了后面的位数；接下来的 1024 位 ( n) 是：

f21a03ef61ad05c0af8d2acf29d3d779c2f73b61aa88533dac358410ac7a08d005dbd6325bb5064eb8afb24e3aef680cfad779d854b7ef97d4f5a1f2f16eb63ebf1b1235f89b65053c01f68a19bcda4183516c20cd907a49301d1314f956fbcc2018e4cfe6991c224d0e177eb11d7fae8477cd6701580754cc116782a0b6b6db

后跟 1024 位 ( e) 是

0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000010001

后者很可能是指数，但在大端：

sage: int.from_bytes(bytes.fromhex('00010001'), 'big')
65537

65537 是一个非常常用的指数。

由于e是大端，我认为n也是，所以你的公共模数是：

sage: int.from_bytes(bytes.fromhex('f21a03ef61ad05c0af8d2acf29d3d779c2f73b61aa88533dac358410ac7a08d005dbd6325bb5064eb8afb24e3aef680cfad779d854b7ef97d4f5a1f2f16eb63ebf1b1235f89b65053c01f68a19bcda4183516c20cd907a49301d1314f956fbcc2018e4cfe6991c224d0e177eb11d7fae8477cd6701580754cc116782a0b6b6db'), 'big')
170009540932613151769038469988293650218844004053584339002200232194264352712884216925985784801458591501781573072892989116728048997832334682982748978655741179946010134561466243581524386945399240608537896417387019700398948330733836779231824938918338194668413830256507020494474648180467264074322450994971415066331

然后，有相同长度的另一个公共密钥00040000以相同e 00010001。

它的公共模数是：

sage: int.from_bytes(bytes.fromhex('af5105fa343e9d8e72294fb8e752a703f54f9b403826f8dd06cf2628ece496806e182ab0e88591f6c0ee7873cb69409e735c62105dd2e28bd45428806836cdb8d94b204ace06d342d24ed824c6988b7db3bd840b50071d291aa4a8cda9187a3f698616fb8ae398f0011a3e38ef31312f07aba316b35858d8e5fe7e7ef8c01209'), 'big')
123111431213688323191113429717081285154340099011946618199498087171573056754335780131987080307395734064403880657942875702088682210145904820435534801337217797703105810136529933603381871426734823683013576987571192787312359697878601542181638347168216122667608679225431011863788903839101406098646701462875195576841
其它你可能感兴趣的问题
上一篇调试器无法附加到所选进程 下一篇'test al, al' 是什么意思？