from Cryptodome.PublicKey import RSA 
from Cryptodome.Cipher import PKCS1_v1_5
from Cryptodome import Random
def encrypt(pub_key_str, msg, length=100):
    """
    单次加密串的长度最大为 (key_size/8)-11
    1024bit的证书用100， 2048bit的证书用 200
    """
    pubobj = RSA.importKey(pub_key_str)
    pubobj = PKCS1_v1_5.new(pubobj)
    res = []
    for i in range(0, len(msg), length):
        res.append(pubobj.encrypt(msg[i:i+length]))
    return "".join(res)


def decrypt(priv_key_str, msg, length=128):
    """
    1024bit的证书用128，2048bit证书用256位
    """
    privobj = RSA.importKey(priv_key_str)
    privobj = PKCS1_v1_5.new(privobj)
    res = []
    for i in range(0, len(msg), length):
        res.append(privobj.decrypt(msg[i:i+length], 'xyz'))
    return "".join(res)
def createkey(len):
    random_generator = Random.new().read
    rsa = RSA.generate(len, random_generator)
    private_pem = rsa.exportKey()
    public_pem = rsa.publickey().exportKey()
    return (public_pem.decode('utf-8'),private_pem.decode('utf-8'))
print(createkey(1024))