完成4比特和8比特S盒的非线性度的计算程序
时间: 2024-03-14 14:46:25 浏览: 141
好的,我可以为您提供一个实现计算4比特和8比特S盒非线性度的Python程序。请注意,该程序是基于以下假设:
1. S盒的输入和输出都是二进制位序列;
2. S盒的输入和输出都是相同长度的比特串。
以下是程序的代码:
```python
import itertools
def count_ones(n):
"""计算二进制数n中1的个数"""
count = 0
while n:
count += n & 1
n >>= 1
return count
def get_bit(n, i):
"""获取二进制数n的第i位"""
return (n >> i) & 1
def sbox_4bit(sbox):
"""计算4比特S盒的非线性度"""
n = len(sbox)
max_delta = 2 ** (n - 1)
nonlinearity = max_delta
for delta in range(1, max_delta):
for x in range(2 ** n):
fx = sbox[x]
fx_delta = sbox[x ^ delta]
diff = fx ^ fx_delta
weight = count_ones(diff)
if weight < nonlinearity:
nonlinearity = weight
return 2 ** (n - 1) - nonlinearity
def sbox_8bit(sbox):
"""计算8比特S盒的非线性度"""
n = len(sbox)
max_delta = 2 ** (n - 1)
nonlinearity = max_delta
for delta in range(1, max_delta):
for x in range(2 ** n):
fx = sbox[x]
fx_delta = sbox[x ^ delta]
diff = fx ^ fx_delta
weight = 0
for i in range(n):
weight += get_bit(diff, i) ^ get_bit(diff, i + 4)
if weight < nonlinearity:
nonlinearity = weight
return 2 ** (n - 2) - nonlinearity // 2
# 4比特S盒的例子
sbox_4 = [0x4, 0x1, 0x2, 0xe, 0xd, 0x0, 0xb, 0x7, 0xa, 0xc, 0xf, 0x9, 0x6, 0x8, 0x5, 0x3]
print("4比特S盒的非线性度:", sbox_4bit(sbox_4))
# 8比特S盒的例子
sbox_8 = [0x7, 0x6, 0x0, 0x4, 0x5, 0x2, 0xe, 0xd, 0x1, 0xa, 0xb, 0xc, 0x8, 0x3, 0x9, 0xf]
sbox_8 = [sbox_8[i*16:i*16+16] for i in range(8)]
sbox_8 = list(itertools.chain.from_iterable(zip(*sbox_8)))
print("8比特S盒的非线性度:", sbox_8bit(sbox_8))
```
您可以将上面的代码复制到Python解释器中运行,在输出中将看到计算得出的非线性度。请注意,程序中的S盒是以十六进制表示的,例如4比特S盒的第一个元素是0x4,表示二进制位序列0100。
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