闲来无事，喝杯茶冷静一下。
TEA
微型加密算法（Tiny Encryption Algorithm，TEA）是一种易于描述和执行的块密码，通常只需要很少的代码就可实现。TEA 操作处理在两个 32 位无符号整型上（可能源于一个 64 位数据），并且使用一个 128 位的密钥。设计者是 Roger Needham 和 David Wheeler。
加密过程：
Python 实现：
#!/usr/bin/env python
def encrypt(v, k):
v0 = v[0]
v1 = v[1]
x = 0
delta = 0x9E3779B9
k0 = k[0]
k1 = k[1]
k2 = k[2]
k3 = k[3]
for i in range(32):
x += delta
x = x & 0xFFFFFFFF
v0 += ((v1 << 4) + k0) ^ (v1 + x) ^ ((v1 >> 5) + k1)
v0 = v0 & 0xFFFFFFFF
v1 += ((v0 << 4) + k2) ^ (v0 + x) ^ ((v0 >> 5) + k3)
v1 = v1 & 0xFFFFFFFF
v[0] = v0
v[1] = v1
return v
def decrypt(v, k):
v0 = v[0]
v1 = v[1]
x = 0xC6EF3720
delta = 0x9E3779B9
k0 = k[0]
k1 = k[1]
k2 = k[2]
k3 = k[3]
for i in range(32):
v1 -= ((v0 << 4) + k2) ^ (v0 + x) ^ ((v0 >> 5) + k3)
v1 = v1 & 0xFFFFFFFF
v0 -= ((v1 << 4) + k0) ^ (v1 + x) ^ ((v1 >> 5) + k1)
v0 = v0 & 0xFFFFFFFF
x -= delta
x = x & 0xFFFFFFFF
v[0] = v0
v[1] = v1
return v
if __name__ == '__main__':
plain = [1, 2]
key = [2, 2, 3, 4]
encrypted = encrypt(plain, key)
print encrypted
decrypted = decrypt(encrypted, key)
print decrypted
XTEA
XTEA 是 TEA 的升级版，增加了更多的密钥表，移位和异或操作等等。
加密过程：
Python 实现：
#!/usr/bin/env python
def encrypt(rounds, v, k):
v0 = v[0]
v1 = v[1]
x = 0
delta = 0x9E3779B9
for i in range(rounds):
v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (x + k[x & 3])
v0 = v0 & 0xFFFFFFFF
x += delta
x = x & 0xFFFFFFFF
v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (x + k[(x >> 11) & 3])
v1 = v1 & 0xFFFFFFFF
v[0] = v0
v[1] = v1
return v
def decrypt(rounds, v, k):
v0 = v[0]
v1 = v[1]
delta = 0x9E3779B9
x = delta * rounds
for i in range(rounds):
v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (x + k[(x >> 11) & 3])
v1 = v1 & 0xFFFFFFFF
x -= delta
x = x & 0xFFFFFFFF
v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (x + k[x & 3])
v0 = v0 & 0xFFFFFFFF
v[0] = v0
v[1] = v1
return v
if __name__ == '__main__':
plain = [1, 2]
key = [2, 2, 3, 4]
rounds = 32
encrypted = encrypt(rounds, plain, key)
print encrypted
decrypted = decrypt(rounds, encrypted, key)
print decrypted
XXTEA
XXTEA，又称 Corrected Block TEA，是 XTEA 的升级版。
加密过程：
Python 实现：
#!/usr/bin/env python
def shift(z, y, x, k, p, e):
return ((((z >> 5) ^ (y << 2)) + ((y >> 3) ^ (z << 4))) ^ ((x ^ y) + (k[(p & 3) ^ e] ^ z)))
def encrypt(v, k):
delta = 0x9E3779B9
n = len(v)
rounds = 6 + 52 / n
x = 0
z = v[n - 1]
for i in range(rounds):
x = (x + delta) & 0xFFFFFFFF
e = (x >> 2) & 3
for p in range(n - 1):
y = v[p + 1]
v[p] = (v[p] + shift(z, y, x, k, p, e)) & 0xFFFFFFFF
z = v[p]
p += 1
y = v[0]
v[n - 1] = (v[n - 1] + shift(z, y, x, k, p, e)) & 0xFFFFFFFF
z = v[n - 1]
return v
def decrypt(v, k):
delta = 0x9E3779B9
n = len(v)
rounds = 6 + 52 / n
x = (rounds * delta) & 0xFFFFFFFF
y = v[0]
for i in range(rounds):
e = (x >> 2) & 3
for p in range(n - 1, 0, -1):
z = v[p - 1]
v[p] = (v[p] - shift(z, y, x, k, p, e)) & 0xFFFFFFFF
y = v[p]
p -= 1
z = v[n - 1]
v[0] = (v[0] - shift(z, y, x, k, p, e)) & 0xFFFFFFFF
y = v[0]
x = (x - delta) & 0xFFFFFFFF
return v
if __name__ == '__main__':
plain = [1, 2]
key = [2, 2, 3, 4]
encrypted = encrypt(plain, key)
print encrypted
decrypted = decrypt(encrypted, key)
print decrypted