使用Python解密IBM生成的JWE时遇InvalidUnwrap错误求助

相关示例 #

JWE: eyJlbmMiOiJBMTI4Q0JDLUhTMjU2IiwiYWxnIjoiQTI1NktXIiwiY3R5IjoiSldUIn0.5Dx7B_0XI8F2ZZzkHjiJkeNsw11LlOuMzln9Z6OuGCAMpLeCOXnnPw.VEV_6HmnlroYO483zJdHFw.jS97NRZaPQfO46J9UvG9YsQ0po2SnUJuCe7M9VNIghD8lyUgdqaGx6xXH6MnAD01VLbjYROwh0z8CFGQ5PbamoiNxzMGM3UHDqvKU4j1pdRkcyPZbyZ6oo-NtY5dlwT6FhMMgu3kk7JKaFKXz0mhyNnvx22QTHKWHpMReEuc4AwdeDBL47iX8kT9cyqBzlGWKl-jLvEM73gUzPLC8RxG9_mtyIzEqyiGWtbDavD4yqf7lgo39jBIvwBu-VDVW05A.o15bGBayvRp9Dgzlqd2WAw

JWK: { "alg": "A256KW", "kty": "oct", "use": "enc", "k": "hD-S5Ll-StGTM6K0N891J3KdAgLVdUNRuKCpiweXJh8", "kid": "test"}

我的Python3代码 #

import base64

from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
from cryptography.hazmat.primitives.keywrap import aes_key_unwrap

encrypted_jwe = ('eyJlbmMiOiJBMTI4Q0JDLUhTMjU2IiwiYWxnIjoiQTI1NktXIiwiY3R5IjoiSldUIn0'
                 '.5Dx7B_0XI8F2ZZzkHjiJkeNsw11LlOuMzln9Z6OuGCAMpLeCOXnnPw.VEV_6HmnlroYO483zJdHFw'
                 '.jS97NRZaPQfO46J9UvG9YsQ0po2SnUJuCe7M9VNIghD8lyUgdqaGx6xXH6MnAD01VLbjYROwh0z8CFGQ5PbamoiNxzMGM3UHDqvKU4j1pdRkcyPZbyZ6oo-NtY5dlwT6FhMMgu3kk7JKaFKXz0mhyNnvx22QTHKWHpMReEuc4AwdeDBL47iX8kT9cyqBzlGWKl-jLvEM73gUzPLC8RxG9_mtyIzEqyiGWtbDavD4yqf7lgo39jBIvwBu-VDVW05A.o15bGBayvRp9Dgzlqd2WAw')


jwk = {
    "kty": "oct",
    "k": "hD-S5Ll-StGTM6K0N891J3KdAgLVdUNRuKCpiweXJh8"
}

parts = encrypted_jwe.split('.')

if len(parts) != 5:
    print("invalid JWE")
    exit(1)

header, encrypted_key, iv, ciphertext, tag = parts


cek_encrypted = base64.urlsafe_b64decode( encrypted_key + '=' * (-len(encrypted_key) % 4))

cek_key = base64.urlsafe_b64decode(jwk['k'] + '=' )

cek = aes_key_unwrap(cek_key, cek_encrypted)


print("decrypted CEK:", cek)


decoded_ciphertext = base64.urlsafe_b64decode(ciphertext + '=' * (-len(ciphertext) % 4))

decoded_iv = base64.urlsafe_b64decode(iv + '=' * (-len(iv) % 4))

cipher = Cipher(algorithms.AES(cek), modes.CBC(decoded_iv), backend=default_backend())

decryptor = cipher.decryptor()
decrypted_payload = decryptor.update(decoded_ciphertext) + decryptor.finalize()

print("decrypted Payload:", decrypted_payload)

我认为的解密步骤 #

• 对JWK对象的k值进行Base64解码
• 对加密后的CEK进行Base64解码，并用步骤1得到的密钥通过A256KW解密
• 使用解密后的CEK创建AES128CBC解密器，结合解码后的IV解密Base64解码后的密文

运行错误 #

cryptography.hazmat.primitives.keywrap.InvalidUnwrap

请问我哪里出错了？急需一份能完成该任务的Python基准脚本，感谢帮助。

内容的提问来源于stack exchange，提问作者docdev