pythonでsha256

#概要

pythonでsha256やってみた。

#参考にしたページ。

https://qiita.com/elm200/items/298636764646de2ef254

#サンプルコード

```
import copy
import struct
import sys

def hexdigest(m):
	return Sha256(m).hexdigest()

class Sha256(object):
	_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)
	_h = (0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19)
	_output_size = 8
	blocksize = 1
	block_size = 64
	digest_size = 32
	def __init__(self, m):
		self._buffer = b''
		self._counter = 0
		if type(m) is not str:
			raise TypeError('%s() argument 1 must be string, not %s' % (self.__class__.__name__, type(m).__name__))
		b = bytearray.fromhex(m)
		self.update(b)
	def _rotr(self, x, y):
		return ((x >> y) | (x << (32 - y))) & 0xFFFFFFFF
	def _sha256_process(self, c):
		w = [0] * 64
		w[0:16] = struct.unpack('!16L', c)
		for i in range(16, 64):
			s0 = self._rotr(w[i - 15], 7) ^ self._rotr(w[i - 15], 18) ^ (w[i - 15] >> 3)
			s1 = self._rotr(w[i - 2], 17) ^ self._rotr(w[i - 2], 19) ^ (w[i - 2] >> 10)
			w[i] = (w[i - 16] + s0 + w[i - 7] + s1) & 0xFFFFFFFF
		a, b, c, d, e, f, g, h = self._h
		for i in range(64):
			s0 = self._rotr(a, 2) ^ self._rotr(a, 13) ^ self._rotr(a, 22)
			maj = (a & b) ^ (a & c) ^ (b & c)
			t2 = s0 + maj
			s1 = self._rotr(e, 6) ^ self._rotr(e, 11) ^ self._rotr(e, 25)
			ch = (e & f) ^ ((~e) & g)
			t1 = h + s1 + ch + self._k[i] + w[i]
			h = g
			g = f
			f = e
			e = (d + t1) & 0xFFFFFFFF
			d = c
			c = b
			b = a
			a = (t1 + t2) & 0xFFFFFFFF
		self._h = [(x + y) & 0xFFFFFFFF for x, y in zip(self._h, [a, b, c, d, e, f, g, h])]
	def update(self, m):
		self._buffer += m
		self._counter += len(m)
		while len(self._buffer) >= 64:
			self._sha256_process(self._buffer[:64])
			self._buffer = self._buffer[64:]
	def digest(self):
		mdi = self._counter & 0x3F
		length = struct.pack('!Q', self._counter << 3)
		if mdi < 56:
			padlen = 55 - mdi
		else:
			padlen = 119 - mdi
		r = self.copy()
		r.update(b'\x80' + (b'\x00' * padlen) + length)
		return b''.join([struct.pack('!L', i) for i in r._h[:self._output_size]])
	def hexdigest(self):
		return self.digest().hex()
	def copy(self):
		return copy.deepcopy(self)

print('in: 616263')
print(hexdigest('616263'))
print('in: ')
print(hexdigest(''))
print('in: d3')
print(hexdigest('d3'))
print('in: 11af')
print(hexdigest('11af'))





```

#結果

```



in: 616263
ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad
in:
e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
in: d3
28969cdfa74a12c82f3bad960b0b000aca2ac329deea5c2328ebc6f2ba9802c1
in: 11af
5ca7133fa735326081558ac312c620eeca9970d1e70a4b95533d956f072d1f98


```

以上。