RSA 非對稱加密

Vibe Prompt

「幫我產生 RSA 2048 金鑰對，用公鑰加密檔案，用私鑰解密。」

實作

from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.asymmetric import rsa, padding
from cryptography.hazmat.primitives import serialization

# 產生金鑰對
private_key = rsa.generate_private_key(public_exponent=65537, key_size=2048)
public_key = private_key.public_key()

# 儲存私鑰
pem_private = private_key.private_bytes(
    encoding=serialization.Encoding.PEM,
    format=serialization.PrivateFormat.PKCS8,
    encryption_algorithm=serialization.NoEncryption()
)
with open('private.pem', 'wb') as f:
    f.write(pem_private)

# 儲存公鑰
pem_public = public_key.public_bytes(
    encoding=serialization.Encoding.PEM,
    format=serialization.PublicFormat.SubjectPublicKeyInfo
)
with open('public.pem', 'wb') as f:
    f.write(pem_public)

# 用公鑰加密
message = b"This is a top secret message"
ciphertext = public_key.encrypt(
    message,
    padding.OAEP(mgf=padding.MGF1(algorithm=hashes.SHA256()),
                  algorithm=hashes.SHA256(), label=None)
)

# 用私鑰解密
plaintext = private_key.decrypt(
    ciphertext,
    padding.OAEP(mgf=padding.MGF1(algorithm=hashes.SHA256()),
                  algorithm=hashes.SHA256(), label=None)
)
print(f"解密: {plaintext.decode()}")

數位簽章

# 簽章
signature = private_key.sign(
    message,
    padding.PSS(mgf=padding.MGF1(hashes.SHA256()), salt_length=padding.PSS.MAX_LENGTH),
    hashes.SHA256()
)

# 驗證
try:
    public_key.verify(
        signature, message,
        padding.PSS(mgf=padding.MGF1(hashes.SHA256()), salt_length=padding.PSS.MAX_LENGTH),
        hashes.SHA256()
    )
    print("✅ 簽章驗證成功！")
except:
    print("❌ 簽章無效！")