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Diffstat (limited to 'frozen_deps/ecdsa/_sha3.py')
-rw-r--r-- | frozen_deps/ecdsa/_sha3.py | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/frozen_deps/ecdsa/_sha3.py b/frozen_deps/ecdsa/_sha3.py new file mode 100644 index 0000000..2db0058 --- /dev/null +++ b/frozen_deps/ecdsa/_sha3.py @@ -0,0 +1,181 @@ +""" +Implementation of the SHAKE-256 algorithm for Ed448 +""" + +try: + import hashlib + + hashlib.new("shake256").digest(64) + + def shake_256(msg, outlen): + return hashlib.new("shake256", msg).digest(outlen) + +except (TypeError, ValueError): + + from ._compat import bytes_to_int, int_to_bytes + + # From little endian. + def _from_le(s): + return bytes_to_int(s, byteorder="little") + + # Rotate a word x by b places to the left. + def _rol(x, b): + return ((x << b) | (x >> (64 - b))) & (2**64 - 1) + + # Do the SHA-3 state transform on state s. + def _sha3_transform(s): + ROTATIONS = [ + 0, + 1, + 62, + 28, + 27, + 36, + 44, + 6, + 55, + 20, + 3, + 10, + 43, + 25, + 39, + 41, + 45, + 15, + 21, + 8, + 18, + 2, + 61, + 56, + 14, + ] + PERMUTATION = [ + 1, + 6, + 9, + 22, + 14, + 20, + 2, + 12, + 13, + 19, + 23, + 15, + 4, + 24, + 21, + 8, + 16, + 5, + 3, + 18, + 17, + 11, + 7, + 10, + ] + RC = [ + 0x0000000000000001, + 0x0000000000008082, + 0x800000000000808A, + 0x8000000080008000, + 0x000000000000808B, + 0x0000000080000001, + 0x8000000080008081, + 0x8000000000008009, + 0x000000000000008A, + 0x0000000000000088, + 0x0000000080008009, + 0x000000008000000A, + 0x000000008000808B, + 0x800000000000008B, + 0x8000000000008089, + 0x8000000000008003, + 0x8000000000008002, + 0x8000000000000080, + 0x000000000000800A, + 0x800000008000000A, + 0x8000000080008081, + 0x8000000000008080, + 0x0000000080000001, + 0x8000000080008008, + ] + + for rnd in range(0, 24): + # AddColumnParity (Theta) + c = [0] * 5 + d = [0] * 5 + for i in range(0, 25): + c[i % 5] ^= s[i] + for i in range(0, 5): + d[i] = c[(i + 4) % 5] ^ _rol(c[(i + 1) % 5], 1) + for i in range(0, 25): + s[i] ^= d[i % 5] + # RotateWords (Rho) + for i in range(0, 25): + s[i] = _rol(s[i], ROTATIONS[i]) + # PermuteWords (Pi) + t = s[PERMUTATION[0]] + for i in range(0, len(PERMUTATION) - 1): + s[PERMUTATION[i]] = s[PERMUTATION[i + 1]] + s[PERMUTATION[-1]] = t + # NonlinearMixRows (Chi) + for i in range(0, 25, 5): + t = [ + s[i], + s[i + 1], + s[i + 2], + s[i + 3], + s[i + 4], + s[i], + s[i + 1], + ] + for j in range(0, 5): + s[i + j] = t[j] ^ ((~t[j + 1]) & (t[j + 2])) + # AddRoundConstant (Iota) + s[0] ^= RC[rnd] + + # Reinterpret octet array b to word array and XOR it to state s. + def _reinterpret_to_words_and_xor(s, b): + for j in range(0, len(b) // 8): + s[j] ^= _from_le(b[8 * j : 8 * j + 8]) + + # Reinterpret word array w to octet array and return it. + def _reinterpret_to_octets(w): + mp = bytearray() + for j in range(0, len(w)): + mp += int_to_bytes(w[j], 8, byteorder="little") + return mp + + def _sha3_raw(msg, r_w, o_p, e_b): + """Semi-generic SHA-3 implementation""" + r_b = 8 * r_w + s = [0] * 25 + # Handle whole blocks. + idx = 0 + blocks = len(msg) // r_b + for i in range(0, blocks): + _reinterpret_to_words_and_xor(s, msg[idx : idx + r_b]) + idx += r_b + _sha3_transform(s) + # Handle last block padding. + m = bytearray(msg[idx:]) + m.append(o_p) + while len(m) < r_b: + m.append(0) + m[len(m) - 1] |= 128 + # Handle padded last block. + _reinterpret_to_words_and_xor(s, m) + _sha3_transform(s) + # Output. + out = bytearray() + while len(out) < e_b: + out += _reinterpret_to_octets(s[:r_w]) + _sha3_transform(s) + return out[:e_b] + + def shake_256(msg, outlen): + return _sha3_raw(msg, 17, 31, outlen) |