TEA、XTEA、XXTEA加密解密算法 - 简书

以下均为标准加解密流程，正式题目中会有魔改

TEA

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def tea_encrypt(v, k, rounds=32):
    v0, v1 = v
    sum = 0
    delta = 0x9E3779B9
    for _ in range(rounds):
        sum = (sum + delta) & 0xFFFFFFFF
        v0 = (v0 + (((v1 << 4) + k[0]) ^ (v1 + sum) ^ ((v1 >> 5) + k[1]))) & 0xFFFFFFFF
        v1 = (v1 + (((v0 << 4) + k[2]) ^ (v0 + sum) ^ ((v0 >> 5) + k[3]))) & 0xFFFFFFFF
    return v0, v1

def tea_decrypt(v, k, rounds=32):
    v0, v1 = v
    delta = 0x9E3779B9
    sum = (delta * rounds) & 0xFFFFFFFF
    for _ in range(rounds):
        v1 = (v1 - (((v0 << 4) + k[2]) ^ (v0 + sum) ^ ((v0 >> 5) + k[3]))) & 0xFFFFFFFF
        v0 = (v0 - (((v1 << 4) + k[0]) ^ (v1 + sum) ^ ((v1 >> 5) + k[1]))) & 0xFFFFFFFF
        sum = (sum - delta) & 0xFFFFFFFF
    return v0, v1


XTEA

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def xtea_encrypt(v, k, rounds=32):
    v0, v1 = v
    sum = 0
    delta = 0x9E3779B9
    for _ in range(rounds):
        v0 = (v0 + (((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]))) & 0xFFFFFFFF
        sum = (sum + delta) & 0xFFFFFFFF
        v1 = (v1 + (((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[(sum >> 11) & 3]))) & 0xFFFFFFFF
    return v0, v1

def xtea_decrypt(v, k, rounds=32):
    v0, v1 = v
    delta = 0x9E3779B9
    sum = (delta * rounds) & 0xFFFFFFFF
    for _ in range(rounds):
        v1 = (v1 - (((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[(sum >> 11) & 3]))) & 0xFFFFFFFF
        sum = (sum - delta) & 0xFFFFFFFF
        v0 = (v0 - (((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]))) & 0xFFFFFFFF
    return v0, v1


XXTEA

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def xxtea_encrypt(data, key):
    def mx(sum, y, z, p, e, k):
        return (((z >> 5 ^ y << 2) + (y >> 3 ^ z << 4)) ^ ((sum ^ y) + (k[(p & 3) ^ e] ^ z))) & 0xFFFFFFFF

    n = len(data)
    if n < 2: return data
    delta = 0x9E3779B9
    rounds = 6 + 52 // n
    sum = 0
    z = data[-1]
    for _ in range(rounds):
        sum = (sum + delta) & 0xFFFFFFFF
        e = (sum >> 2) & 3
        for p in range(n - 1):
            y = data[p + 1]
            data[p] = (data[p] + mx(sum, y, z, p, e, key)) & 0xFFFFFFFF
            z = data[p]
        y = data[0]
        data[-1] = (data[-1] + mx(sum, y, z, n - 1, e, key)) & 0xFFFFFFFF
    return data

def xxtea_decrypt(data, key):
    def mx(sum, y, z, p, e, k):
        return (((z >> 5 ^ y << 2) + (y >> 3 ^ z << 4)) ^ ((sum ^ y) + (k[(p & 3) ^ e] ^ z))) & 0xFFFFFFFF

    n = len(data)
    if n < 2: return data
    delta = 0x9E3779B9
    rounds = 6 + 52 // n
    sum = (rounds * delta) & 0xFFFFFFFF
    y = data[0]
    for _ in range(rounds):
        e = (sum >> 2) & 3
        for p in range(n - 1, 0, -1):
            z = data[p - 1]
            data[p] = (data[p] - mx(sum, y, z, p, e, key)) & 0xFFFFFFFF
            y = data[p]
        z = data[-1]
        data[0] = (data[0] - mx(sum, y, z, 0, e, key)) & 0xFFFFFFFF
        sum = (sum - delta) & 0xFFFFFFFF
    return data