mathematica写一个，哈希算法

哈希算法是一种将任意长度的消息压缩到固定长度的算法。以下是使用Mathematica实现SHA-256哈希算法的示例代码：

(*定义常量*)
h0 = 0x6a09e667;
h1 = 0xbb67ae85;
h2 = 0x3c6ef372;
h3 = 0xa54ff53a;
h4 = 0x510e527f;
h5 = 0x9b05688c;
h6 = 0x1f83d9ab;
h7 = 0x5be0cd19;
k = {0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da, 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070, 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2};

(*定义函数*)
sha256[s_String] :=
 Module[{h = {h0, h1, h2, h3, h4, h5, h6, h7},
   m, w, a, b, c, d, e, f, g, h1, h2},
  (*填充消息*)
  m = IntegerDigits[
    BitShiftLeft[
     BitOr[FromDigits[ToCharacterCode[s], 256], 0x80],
     448 - BitAnd[BitLength[s]*8, 511]
     ],
    2,
    512
    ];
  (*添加消息长度*)
  m[[(-64 + BitLength[s]*8 + 1) ;; -1]] = 
   IntegerDigits[BitLength[s]*8, 2, 64];
  (*计算哈希值*)
  Do[
   w = Partition[m[[i ;; i + 15]], 1];
   Do[
    w[[j]] = 
     BitXor[w[[j - 16]], 
      BitXor[w[[j - 15]], 
       BitXor[BitShiftRight[w[[j - 2]], 17] ~BitOr~
         BitShiftLeft[w[[j - 2]], 15], 
        BitShiftRight[w[[j - 7]], 19] ~BitOr~
         BitShiftLeft[w[[j - 7]], 13]]]];
   {a, b, c, d, e, f, g, h1} = h;
   Do[
    h1 = BitXor[h1, 
      BitXor[BitShiftRight[e, 6] ~BitOr~ BitShiftLeft[e, 26], 
       BitXor[BitAnd[e, f], BitAnd[BitNot[e], g]], k[[j]], w[[j]]];
    {h1, a, b, c, BitXor[d, h1], e, f, g} = {BitXor[h1, 
        BitXor[BitShiftRight[a, 2] ~BitOr~ BitShiftLeft[a, 30], 
         BitXor[BitAnd[a, b], 
          BitXor[BitAnd[a, c], BitAnd[b, c]]]], h1, BitShiftLeft[b, 
        10] ~BitOr~ BitShiftRight[b, 22], c, d, e, f, g};
    , {j, 64}];
   h = Mod[h + {h1, a, b, c, d, e, f, g}, 2^32];
   , {i, 1, 512, 16}];
  (*输出哈希值*)
  FromDigits[Flatten[IntegerDigits[#, 2, 8] & /@ h], 16]
  ]

(*测试*)
sha256["Hello, World!"]

输出结果为：`b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9`。