帮我写一个python的RC4加解密代码

当然，我可以帮你写一个Python的RC4加解密代码。以下是代码：

def KSA(key):
    # 初始化S盒
    S = list(range(256))
    j = 0
    for i in range(256):
        j = (j + S[i] + key[i % len(key)]) % 256
        S[i], S[j] = S[j], S[i]
    return S

def PRGA(S):
    # 生成密钥流
    i = 0
    j = 0
    while True:
        i = (i + 1) % 256
        j = (j + S[i]) % 256
        S[i], S[j] = S[j], S[i]
        K = S[(S[i] + S[j]) % 256]
        yield K

def RC4(key, data):
    S = KSA(key)
    key_stream = PRGA(S)
    res = []
    for d in data:
        res.append(d ^ next(key_stream))
    return bytes(res)

# 加密
key = b'example_key'
plaintext = b'hello world'
ciphertext = RC4(key, plaintext)
print(ciphertext)

# 解密
plaintext = RC4(key, ciphertext)
print(plaintext)

其中，`KSA`函数用于初始化S盒，`PRGA`函数用于生成密钥流，`RC4`函数实现RC4加解密。你可以将`key`和`data`替换成你需要加解密的内容。