Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/jose/backends/native.py: 38%

1import hashlib 

2import hmac 

3import os 

4 

5from jose.backends.base import Key 

6from jose.constants import ALGORITHMS 

7from jose.exceptions import JWKError 

8from jose.utils import base64url_decode, base64url_encode, is_pem_format, is_ssh_key 

9 

10 

11def get_random_bytes(num_bytes): 

12 return bytes(os.urandom(num_bytes)) 

13 

14 

15class HMACKey(Key): 

16 """ 

17 Performs signing and verification operations using HMAC 

18 and the specified hash function. 

19 """ 

20 

21 HASHES = {ALGORITHMS.HS256: hashlib.sha256, ALGORITHMS.HS384: hashlib.sha384, ALGORITHMS.HS512: hashlib.sha512} 

22 

23 def __init__(self, key, algorithm): 

24 if algorithm not in ALGORITHMS.HMAC: 

25 raise JWKError("hash_alg: %s is not a valid hash algorithm" % algorithm) 

26 self._algorithm = algorithm 

27 self._hash_alg = self.HASHES.get(algorithm) 

28 

29 if isinstance(key, dict): 

30 self.prepared_key = self._process_jwk(key) 

31 return 

32 

33 if not isinstance(key, str) and not isinstance(key, bytes): 

34 raise JWKError("Expecting a string- or bytes-formatted key.") 

35 

36 if isinstance(key, str): 

37 key = key.encode("utf-8") 

38 

39 if is_pem_format(key) or is_ssh_key(key): 

40 raise JWKError( 

41 "The specified key is an asymmetric key or x509 certificate and" 

42 " should not be used as an HMAC secret." 

43 ) 

44 

45 self.prepared_key = key 

46 

47 def _process_jwk(self, jwk_dict): 

48 if not jwk_dict.get("kty") == "oct": 

49 raise JWKError("Incorrect key type. Expected: 'oct', Received: %s" % jwk_dict.get("kty")) 

50 

51 k = jwk_dict.get("k") 

52 k = k.encode("utf-8") 

53 k = bytes(k) 

54 k = base64url_decode(k) 

55 

56 return k 

57 

58 def sign(self, msg): 

59 return hmac.new(self.prepared_key, msg, self._hash_alg).digest() 

60 

61 def verify(self, msg, sig): 

62 return hmac.compare_digest(sig, self.sign(msg)) 

63 

64 def to_dict(self): 

65 return { 

66 "alg": self._algorithm, 

67 "kty": "oct", 

68 "k": base64url_encode(self.prepared_key).decode("ASCII"), 

69 }