whale-fall-code
2bb83f3685
App 端免签名接口（设备注册 + detail + CDN 直链），一体化流水线 下载→抽音→传COS→记录→删本地，AI 作品四档判定，四份文档： README（使用指南）、PROGRESS（批次进度）、RE（逆向全过程）、AI（判定规则）。 Co-Authored-By: Claude Code <noreply@anthropic.com>
180 lines
5.6 KiB
Python
180 lines
5.6 KiB
Python
"""a_bogus 依赖的底层密码学原语：SM3、RC4、自定义 Base64。
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这三样都是公开算法，与抖音无关，可以独立验证正确性：
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- SM3 见 GB/T 32905-2016，本文件底部带官方测试向量自检
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- RC4 标准流密码
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- 自定义 Base64 只是把标准码表换成抖音自己那套字符顺序
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"""
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from __future__ import annotations
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from typing import Iterable, List, Sequence
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# --------------------------------------------------------------------------- #
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# SM3
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# --------------------------------------------------------------------------- #
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_IV = [
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0x7380166F, 0x4914B2B9, 0x172442D7, 0xDA8A0600,
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0xA96F30BC, 0x163138AA, 0xE38DEE4D, 0xB0FB0E4E,
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]
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_MASK = 0xFFFFFFFF
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def _rotl(x: int, n: int) -> int:
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n &= 31
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return ((x << n) | (x >> (32 - n))) & _MASK
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def _ff(j: int, x: int, y: int, z: int) -> int:
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return (x ^ y ^ z) if j < 16 else ((x & y) | (x & z) | (y & z))
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def _gg(j: int, x: int, y: int, z: int) -> int:
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return (x ^ y ^ z) if j < 16 else ((x & y) | ((~x & _MASK) & z))
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def _p0(x: int) -> int:
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return x ^ _rotl(x, 9) ^ _rotl(x, 17)
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def _p1(x: int) -> int:
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return x ^ _rotl(x, 15) ^ _rotl(x, 23)
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def _cf(v: Sequence[int], block: bytes) -> List[int]:
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"""压缩函数 CF(V, B)。"""
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w = [int.from_bytes(block[i * 4:i * 4 + 4], "big") for i in range(16)]
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for j in range(16, 68):
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w.append(
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_p1(w[j - 16] ^ w[j - 9] ^ _rotl(w[j - 3], 15))
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^ _rotl(w[j - 13], 7)
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^ w[j - 6]
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)
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w1 = [w[j] ^ w[j + 4] for j in range(64)]
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a, b, c, d, e, f, g, h = v
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for j in range(64):
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t = 0x79CC4519 if j < 16 else 0x7A879D8A
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ss1 = _rotl((_rotl(a, 12) + e + _rotl(t, j)) & _MASK, 7)
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ss2 = ss1 ^ _rotl(a, 12)
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tt1 = (_ff(j, a, b, c) + d + ss2 + w1[j]) & _MASK
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tt2 = (_gg(j, e, f, g) + h + ss1 + w[j]) & _MASK
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d = c
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c = _rotl(b, 9)
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b = a
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a = tt1
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h = g
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g = _rotl(f, 19)
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f = e
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e = _p0(tt2)
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return [x ^ y for x, y in zip(v, (a, b, c, d, e, f, g, h))]
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def sm3(data: bytes) -> bytes:
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"""SM3 摘要，返回 32 字节。"""
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bit_len = len(data) * 8
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padded = data + b"\x80"
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padded += b"\x00" * ((56 - len(padded) % 64) % 64)
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padded += bit_len.to_bytes(8, "big")
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v = list(_IV)
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for i in range(0, len(padded), 64):
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v = _cf(v, padded[i:i + 64])
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return b"".join(x.to_bytes(4, "big") for x in v)
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def sm3_to_list(data: bytes | Iterable[int]) -> List[int]:
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"""SM3 摘要，返回 32 个 int（a_bogus 内部按字节数组传递）。"""
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if not isinstance(data, (bytes, bytearray)):
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data = bytes(bytearray(data))
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return list(sm3(bytes(data)))
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# --------------------------------------------------------------------------- #
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# RC4
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# --------------------------------------------------------------------------- #
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def rc4(key: bytes, data: bytes) -> bytes:
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"""标准 RC4。加解密同一函数。"""
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s = list(range(256))
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j = 0
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klen = len(key)
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for i in range(256):
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j = (j + s[i] + key[i % klen]) & 0xFF
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s[i], s[j] = s[j], s[i]
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out = bytearray(len(data))
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i = j = 0
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for n, ch in enumerate(data):
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i = (i + 1) & 0xFF
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j = (j + s[i]) & 0xFF
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s[i], s[j] = s[j], s[i]
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out[n] = ch ^ s[(s[i] + s[j]) & 0xFF]
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return bytes(out)
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# --------------------------------------------------------------------------- #
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# 自定义码表 Base64
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# --------------------------------------------------------------------------- #
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STD_ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="
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def b64_encode(data: bytes, alphabet: str, pad: bool = True) -> str:
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"""按给定 64(+1) 字符码表做 Base64 编码。
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alphabet 长度为 64 时不补位；为 65 时最后一位作为填充字符。
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"""
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if len(alphabet) not in (64, 65):
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raise ValueError(f"码表长度必须是 64 或 65，收到 {len(alphabet)}")
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fill = alphabet[64] if len(alphabet) == 65 else ""
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out: List[str] = []
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for i in range(0, len(data), 3):
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chunk = data[i:i + 3]
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n = int.from_bytes(chunk + b"\x00" * (3 - len(chunk)), "big")
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quad = [alphabet[(n >> shift) & 0x3F] for shift in (18, 12, 6, 0)]
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keep = len(chunk) + 1 # 1字节->2字符, 2字节->3字符, 3字节->4字符
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out.extend(quad[:keep])
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if pad and fill:
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out.extend(fill * (4 - keep))
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return "".join(out)
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# --------------------------------------------------------------------------- #
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# 自检
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# --------------------------------------------------------------------------- #
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# GB/T 32905-2016 附录 A 给出的两组标准测试向量
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_SM3_VECTORS = [
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(b"abc",
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"66c7f0f462eeedd9d1f2d46bdc10e4e24167c4875cf2f7a2297da02b8f4ba8e0"),
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(b"abcd" * 16,
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"debe9ff92275b8a138604889c18e5a4d6fdb70e5387e5765293dcba39c0c5732"),
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]
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def self_test() -> None:
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"""跑通即说明 SM3/RC4/Base64 实现无误。"""
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for msg, want in _SM3_VECTORS:
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got = sm3(msg).hex()
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assert got == want, f"SM3({msg[:8]!r}...) = {got}, 期望 {want}"
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# RC4 官方测试向量：key="Key", plaintext="Plaintext" -> BBF316E8D940AF0AD3
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assert rc4(b"Key", b"Plaintext").hex().upper() == "BBF316E8D940AF0AD3"
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# 用标准码表时，自定义 Base64 应与 base64 模块完全一致
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import base64
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import os
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for n in range(1, 40):
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raw = os.urandom(n)
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assert b64_encode(raw, STD_ALPHABET) == base64.b64encode(raw).decode()
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print("crypto self-test OK: SM3 / RC4 / custom-base64 均通过")
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if __name__ == "__main__":
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self_test()
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