Python 常用加密算法实现 - AES、RSA、ECC、DES、3DES、Rabin、ElGamal、Diffie-Hellman

以下是使用 Python 实现常见加密算法的代码示例：

1. AES 算法加密实现：

from Crypto.Cipher import AES
from Crypto.Random import get_random_bytes

def encrypt_aes(key, plaintext):
    cipher = AES.new(key, AES.MODE_EAX)
    nonce = cipher.nonce
    ciphertext, tag = cipher.encrypt_and_digest(plaintext.encode())
    return nonce + ciphertext

def decrypt_aes(key, ciphertext):
    nonce = ciphertext[:16]
    ciphertext = ciphertext[16:]
    cipher = AES.new(key, AES.MODE_EAX, nonce)
    plaintext = cipher.decrypt(ciphertext)
    return plaintext.decode()

2. RSA 算法加密实现：

from Crypto.PublicKey import RSA
from Crypto.Cipher import PKCS1_OAEP

def generate_rsa_keypair():
    key = RSA.generate(2048)
    private_key = key.export_key()
    public_key = key.publickey().export_key()
    return private_key, public_key

def encrypt_rsa(public_key, plaintext):
    key = RSA.import_key(public_key)
    cipher = PKCS1_OAEP.new(key)
    ciphertext = cipher.encrypt(plaintext.encode())
    return ciphertext

def decrypt_rsa(private_key, ciphertext):
    key = RSA.import_key(private_key)
    cipher = PKCS1_OAEP.new(key)
    plaintext = cipher.decrypt(ciphertext)
    return plaintext.decode()

3. ECC 算法加密实现：

from cryptography.hazmat.primitives.asymmetric import ec
from cryptography.hazmat.primitives import serialization

def generate_ecc_keypair():
    private_key = ec.generate_private_key(ec.SECP256R1())
    public_key = private_key.public_key()
    private_key_bytes = private_key.private_bytes(encoding=serialization.Encoding.PEM, format=serialization.PrivateFormat.PKCS8, encryption_algorithm=serialization.NoEncryption())
    public_key_bytes = public_key.public_bytes(encoding=serialization.Encoding.PEM, format=serialization.PublicFormat.SubjectPublicKeyInfo)
    return private_key_bytes, public_key_bytes

def encrypt_ecc(public_key, plaintext):
    public_key = serialization.load_pem_public_key(public_key)
    ciphertext = public_key.encrypt(plaintext.encode(), ec.ECIES())
    return ciphertext

def decrypt_ecc(private_key, ciphertext):
    private_key = serialization.load_pem_private_key(private_key, password=None)
    plaintext = private_key.decrypt(ciphertext, ec.ECIES())
    return plaintext.decode()

4. DES 算法加密实现：

from Crypto.Cipher import DES

def encrypt_des(key, plaintext):
    cipher = DES.new(key, DES.MODE_ECB)
    ciphertext = cipher.encrypt(plaintext.encode())
    return ciphertext

def decrypt_des(key, ciphertext):
    cipher = DES.new(key, DES.MODE_ECB)
    plaintext = cipher.decrypt(ciphertext)
    return plaintext.decode()

5. 3DES 算法加密实现：

from Crypto.Cipher import DES3

def encrypt_3des(key, plaintext):
    cipher = DES3.new(key, DES3.MODE_ECB)
    ciphertext = cipher.encrypt(plaintext.encode())
    return ciphertext

def decrypt_3des(key, ciphertext):
    cipher = DES3.new(key, DES3.MODE_ECB)
    plaintext = cipher.decrypt(ciphertext)
    return plaintext.decode()

6. Rabin 算法加密实现：

from Crypto.PublicKey import Rabin
from Crypto.Cipher import PKCS1_OAEP

def generate_rabin_keypair():
    key = Rabin.generate(2048)
    private_key = key.export_key()
    public_key = key.publickey().export_key()
    return private_key, public_key

def encrypt_rabin(public_key, plaintext):
    key = Rabin.import_key(public_key)
    cipher = PKCS1_OAEP.new(key)
    ciphertext = cipher.encrypt(plaintext.encode())
    return ciphertext

def decrypt_rabin(private_key, ciphertext):
    key = Rabin.import_key(private_key)
    cipher = PKCS1_OAEP.new(key)
    plaintext = cipher.decrypt(ciphertext)
    return plaintext.decode()

7. ElGamal 算法加密实现：

from Crypto.PublicKey import ElGamal
from Crypto.Cipher import PKCS1_OAEP

def generate_elgamal_keypair():
    key = ElGamal.generate(2048)
    private_key = key.export_key()
    public_key = key.publickey().export_key()
    return private_key, public_key

def encrypt_elgamal(public_key, plaintext):
    key = ElGamal.import_key(public_key)
    cipher = PKCS1_OAEP.new(key)
    ciphertext = cipher.encrypt(plaintext.encode())
    return ciphertext

def decrypt_elgamal(private_key, ciphertext):
    key = ElGamal.import_key(private_key)
    cipher = PKCS1_OAEP.new(key)
    plaintext = cipher.decrypt(ciphertext)
    return plaintext.decode()

8. Diffie-Hellman 算法密钥交换实现：

from cryptography.hazmat.primitives.asymmetric import dh
from cryptography.hazmat.primitives import serialization

def generate_dh_keypair():
    parameters = dh.generate_parameters(generator=2, key_size=2048)
    private_key = parameters.generate_private_key()
    public_key = private_key.public_key()
    private_key_bytes = private_key.private_bytes(encoding=serialization.Encoding.PEM, format=serialization.PrivateFormat.PKCS8, encryption_algorithm=serialization.NoEncryption())
    public_key_bytes = public_key.public_bytes(encoding=serialization.Encoding.PEM, format=serialization.PublicFormat.SubjectPublicKeyInfo)
    return private_key_bytes, public_key_bytes

def derive_dh_shared_key(private_key, peer_public_key):
    private_key = serialization.load_pem_private_key(private_key, password=None)
    peer_public_key = serialization.load_pem_public_key(peer_public_key)
    shared_key = private_key.exchange(peer_public_key)
    return shared_key

以上代码示例中使用了一些第三方库，如 pycryptodome 和 cryptography，需要通过安装对应的库来使用。