使用pycryptodome计算ecies hkdf对称密钥

from Crypto.PublicKey import ECC
from Crypto.Cipher import AES, PKCS1_OAEP
from Crypto.Random import get_random_bytes
from Crypto.Hash import HMAC, SHA256

# 生成椭圆曲线密钥对
key = ECC.generate(curve='P-256')
private_key = key.export_key(format='DER')
public_key = key.public_key().export_key(format='DER')

# 假设对方公钥已知
peer_public_key = ECC.import_key(public_key)

# 使用HKDF派生对称密钥
shared_secret = peer_public_key.pointQ.x().to_bytes(32, 'big')
hkdf = HMAC.new(shared_secret, digestmod=SHA256)
hkdf.update(b'context information')
symmetric_key = hkdf.digest()[:16]  # 使用前16字节作为AES密钥

# 使用对称密钥加密数据
cipher = AES.new(symmetric_key, AES.MODE_EAX)
nonce = cipher.nonce
ciphertext, tag = cipher.encrypt_and_digest(b'secret data')

# 解密数据
cipher = AES.new(symmetric_key, AES.MODE_EAX, nonce=nonce)
plaintext = cipher.decrypt_and_verify(ciphertext, tag)

print("Plaintext:", plaintext.decode())