1 """Class for storing SRP password verifiers."""
3 from utils.cryptomath import *
4 from utils.compat import *
6 from BaseDB import BaseDB
8 class VerifierDB(BaseDB):
9 """This class represent an in-memory or on-disk database of SRP
12 A VerifierDB can be passed to a server handshake to authenticate
13 a client based on one of the verifiers.
15 This class is thread-safe.
17 def __init__(self, filename=None):
18 """Create a new VerifierDB instance.
21 @param filename: Filename for an on-disk database, or None for
22 an in-memory database. If the filename already exists, follow
23 this with a call to open(). To create a new on-disk database,
24 follow this with a call to create().
26 BaseDB.__init__(self, filename, "verifier")
28 def _getItem(self, username, valueStr):
29 (N, g, salt, verifier) = valueStr.split(" ")
32 salt = base64ToString(salt)
33 verifier = base64ToNumber(verifier)
34 return (N, g, salt, verifier)
36 def __setitem__(self, username, verifierEntry):
37 """Add a verifier entry to the database.
40 @param username: The username to associate the verifier with.
41 Must be less than 256 characters in length. Must not already
44 @type verifierEntry: tuple
45 @param verifierEntry: The verifier entry to add. Use
46 L{tlslite.VerifierDB.VerifierDB.makeVerifier} to create a
49 BaseDB.__setitem__(self, username, verifierEntry)
52 def _setItem(self, username, value):
53 if len(username)>=256:
54 raise ValueError("username too long")
55 N, g, salt, verifier = value
58 salt = stringToBase64(salt)
59 verifier = numberToBase64(verifier)
60 valueStr = " ".join( (N, g, salt, verifier) )
63 def _checkItem(self, value, username, param):
64 (N, g, salt, verifier) = value
65 x = mathtls.makeX(salt, username, param)
67 return (verifier == v)
70 def makeVerifier(username, password, bits):
71 """Create a verifier entry which can be stored in a VerifierDB.
74 @param username: The username for this verifier. Must be less
75 than 256 characters in length.
78 @param password: The password for this verifier.
81 @param bits: This values specifies which SRP group parameters
82 to use. It must be one of (1024, 1536, 2048, 3072, 4096, 6144,
83 8192). Larger values are more secure but slower. 2048 is a
84 good compromise between safety and speed.
87 @return: A tuple which may be stored in a VerifierDB.
89 return mathtls.makeVerifier(username, password, bits)
90 makeVerifier = staticmethod(makeVerifier)