Python中cryptography.hazmat.backends.openssl.x509模块的证书链验证方法

cryptography.hazmat.backends.openssl.x509模块提供了一些用于证书链验证的方法，可以用于验证X.509证书链的完整性和有效性。下面是一些常用的方法和使用示例。

1. verify_certificate_chain方法

verify_certificate_chain方法用于验证证书链的完整性和有效性。该方法需要传入一个证书链列表，其中包含待验证的证书链。

from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric import rsa
from cryptography import x509
from cryptography.x509.oid import NameOID
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import hashes
from cryptography.x509 import load_pem_x509_certificate
from cryptography.hazmat.backends.openssl.x509 import (
    load_certificate_request_data, X509Req
)
from cryptography.hazmat.primitives.asymmetric import padding

def create_self_signed_cert():
    # 生成RSA私钥
    private_key = rsa.generate_private_key(
        public_exponent=65537,
        key_size=2048,
        backend=default_backend()
    )
    # 构建X.509证书
    subject = issuer = x509.Name([
        x509.NameAttribute(NameOID.COUNTRY_NAME, u"CN"),
        x509.NameAttribute(NameOID.STATE_OR_PROVINCE_NAME, u"Shandong"),
        x509.NameAttribute(NameOID.LOCALITY_NAME, u"Qingdao"),
        x509.NameAttribute(NameOID.ORGANIZATION_NAME, u"Example Company"),
        x509.NameAttribute(NameOID.COMMON_NAME, u"example.com"),
    ])
    cert = x509.CertificateBuilder().subject_name(
        subject
    ).issuer_name(
        issuer
    ).public_key(
        private_key.public_key()
    ).serial_number(
        x509.random_serial_number()
    ).not_valid_before(
        datetime.datetime.utcnow()
    ).not_valid_after(
        datetime.datetime.utcnow() + datetime.timedelta(days=10)
    ).sign(private_key, hashes.SHA256(), default_backend())

    return cert, private_key

# 创建自签名证书和私钥
cert, private_key = create_self_signed_cert()

# 将证书链中添加自签名证书
cert_chain = [cert]

# 验证证书链的完整性和有效性
try:
    x509.verify_certificate_chain(cert_chain)
    print("Certificate chain is valid")
except x509.InvalidCertificate as e:
    print("Invalid certificate chain:", e)

2. check_signature方法

check_signature方法用于验证证书的签名是否正确。该方法需要传入待验证的证书和签名算法。

from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import hashes, serialization
from cryptography.hazmat.primitives.asymmetric import padding

# 创建一个X.509证书对象
cert = load_pem_x509_certificate(cert_data, default_backend())

# 验证证书的签名是否正确
try:
    cert.public_key().verify(
        cert.signature,
        cert.tbs_certificate_bytes,
        padding.PKCS1v15(),
        cert.signature_hash_algorithm
    )
    print("Certificate signature is valid")
except InvalidSignature as e:
    print("Invalid certificate signature:", e)

以上是cryptography.hazmat.backends.openssl.x509模块中验证证书链的方法及其使用示例。通过这些方法，你可以验证X.509证书链的完整性和有效性，以确保证书的安全性。