1
import hashlib, base64, secrets
2

3
# Step 1: 生成 code_verifier（高熵随机字符串，43-128 chars）
4
code_verifier = base64.urlsafe_b64encode(secrets.token_bytes(32)).rstrip(b'=').decode()
5

6
# Step 2: 计算 code_challenge = BASE64URL(SHA256(code_verifier))
7
code_challenge = base64.urlsafe_b64encode(
8
    hashlib.sha256(code_verifier.encode()).digest()
9
).rstrip(b'=').decode()
10

11
print(f"code_verifier:  {code_verifier}")
12
print(f"code_challenge: {code_challenge}")

1
code_verifier:  U7j1QxRl9HRvlszG63RFQqVcMzW1Jr181yczQAjqLyk
2
code_challenge: hoZLEUI4_x5OuPB068oKDKNtCdjGXRS_EcaXcKRb4-s

1
import json, base64
2

3
# 模拟一个 ES256 JWT
4
token = "eyJhbGciOiJFUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJhdXRoLXNlcnZlciIsInN1YiI6InVzZXItMTIzNDUiLCJhdWQiOiJteS1hcHAiLCJleHAiOjE3NzgxNjQ5MjQsImlhdCI6MTc3ODE2NDAyNH0.signature"
5

6
# 解码 Header
7
header = json.loads(base64.urlsafe_b64decode(token.split('.')[0] + '=='))
8
print(f"Header: {json.dumps(header, indent=2)}")
9

10
# 解码 Payload
11
payload = json.loads(base64.urlsafe_b64decode(token.split('.')[1] + '=='))
12
print(f"Payload: {json.dumps(payload, indent=2)}")

1
Header: {
2
  "alg": "ES256",
3
  "typ": "JWT"
4
}
5
Payload: {
6
  "iss": "auth-server",
7
  "sub": "user-12345",
8
  "aud": "my-app",
9
  "exp": 1778164924,
10
  "iat": 1778164024
11
}

1
{
2
  "keys": [
3
    {
4
      "kty": "EC",
5
      "kid": "key-2024-01",
6
      "crv": "P-256",
7
      "x": "WKn-ZIGevcwGIyyrzFoZNBdaq9_TsqzGl96oc0CWuis",
8
      "y": "M77RAy4FqQO7L7jC5E0f0VRqXeS0a5fSQh2gFC7Lqms",
9
      "use": "sig",
10
      "alg": "ES256"
11
    },
12
    {
13
      "kty": "EC",
14
      "kid": "key-2024-02",
15
      "crv": "P-256",
16
      "x": "new-key-x-value-here",
17
      "y": "new-key-y-value-here",
18
      "use": "sig",
19
      "alg": "ES256"
20
    }
21
  ]
22
}

1
import jwt, json, base64
2

3
# 构造 alg=none 的伪造 Token
4
header = base64.urlsafe_b64encode(
5
    json.dumps({"alg": "none", "typ": "JWT"}).encode()
6
).rstrip(b'=').decode()
7
payload = base64.urlsafe_b64encode(
8
    json.dumps({"sub": "admin", "role": "admin"}).encode()
9
).rstrip(b'=').decode()
10
forged_token = f"{header}.{payload}."
11

12
# 现代库会拒绝 none 算法
13
try:
14
    decoded = jwt.decode(forged_token, public_key, algorithms=["ES256"])
15
    print("  alg=none 攻击成功！")
16
except jwt.InvalidAlgorithmError:
17
    print(" alg=none 攻击被防御")

1
 alg=none 攻击被防御

1
# 构造 alg=HS256 的伪造 Token（用公钥作 HMAC 密钥）
2
try:
3
    decoded = jwt.decode(hs256_forged_token, public_pem, algorithms=["HS256"])
4
    print("  算法混淆攻击成功！")
5
except jwt.InvalidKeyError:
6
    print(" 算法混淆攻击被防御")

1
 算法混淆攻击被防御

1
# 签发一个已过期的 Token
2
expired_token = jwt.encode(
3
    {"sub": "user123", "exp": now - 3600},
4
    private_key, algorithm="ES256"
5
)
6
try:
7
    jwt.decode(expired_token, public_key, algorithms=["ES256"])
8
except jwt.ExpiredSignatureError:
9
    print(" 过期 Token 被拒绝")

1
 过期 Token 被拒绝