diff options
Diffstat (limited to 'Lib/hmac.py')
| -rw-r--r-- | Lib/hmac.py | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/Lib/hmac.py b/Lib/hmac.py index 1911689ea7..6f2ae2e110 100644 --- a/Lib/hmac.py +++ b/Lib/hmac.py @@ -3,6 +3,8 @@ Implements the HMAC algorithm as described by RFC 2104. """ +import warnings as _warnings + trans_5C = bytes((x ^ 0x5C) for x in range(256)) trans_36 = bytes((x ^ 0x36) for x in range(256)) @@ -16,7 +18,7 @@ digest_size = None _secret_backdoor_key = [] class HMAC: - """RFC2104 HMAC class. + """RFC 2104 HMAC class. Also complies with RFC 4231. This supports the API for Cryptographic Hash Functions (PEP 247). """ @@ -52,7 +54,21 @@ class HMAC: self.inner = self.digest_cons() self.digest_size = self.inner.digest_size - blocksize = self.blocksize + if hasattr(self.inner, 'block_size'): + blocksize = self.inner.block_size + if blocksize < 16: + # Very low blocksize, most likely a legacy value like + # Lib/sha.py and Lib/md5.py have. + _warnings.warn('block_size of %d seems too small; using our ' + 'default of %d.' % (blocksize, self.blocksize), + RuntimeWarning, 2) + blocksize = self.blocksize + else: + _warnings.warn('No block_size attribute on given digest object; ' + 'Assuming %d.' % (self.blocksize), + RuntimeWarning, 2) + blocksize = self.blocksize + if len(key) > blocksize: key = self.digest_cons(key).digest() |