1 files changed, 62 insertions, 23 deletions
diff --git a/lib/Crypto/Hash/SHA224.py b/lib/Crypto/Hash/SHA224.py
index 872ed81..959b56d 100644
--- a/lib/Crypto/Hash/SHA224.py
+++ b/lib/Crypto/Hash/SHA224.py
@@ -18,31 +18,28 @@
 # SOFTWARE.
 # ===================================================================
 
-# Just use the SHA module from the Python standard library
+"""SHA-224 cryptographic hash algorithm.
 
-__revision__ = "$Id$"
+SHA-224 belongs to the SHA-2_ family of cryptographic hashes.
+It produces the 224 bit digest of a message.
 
-__all__ = ['new', 'digest_size']
+    >>> from Crypto.Hash import SHA224
+    >>>
+    >>> h = SHA224.new()
+    >>> h.update(b'Hello')
+    >>> print h.hexdigest()
 
-from Crypto.Util.wrapper import Wrapper
-from Crypto.Util.py3compat import *
+*SHA* stands for Secure Hash Algorithm.
 
-# The OID for SHA-224 is:
-#
-# id-sha224    OBJECT IDENTIFIER ::= {
-#			joint-iso-itu-t(2)
-#			country(16) us(840) organization(1) gov(101) csor(3)
-#			nistalgorithm(4) hashalgs(2) 4
-#		}
-oid = b('\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x04')
-
-def new(data=b("")):
-    obj = Wrapper(hashFactory, data)
-    obj.oid = oid
-    obj.new = globals()['new']
-    if not hasattr(obj, 'digest_size'):
-        obj.digest_size = digest_size
-    return obj
+.. _SHA-2: http://csrc.nist.gov/publications/fips/fips180-2/fips180-2.pdf
+"""
+
+_revision__ = "$Id$"
+
+__all__ = ['new', 'digest_size', 'SHA224Hash' ]
+
+from Crypto.Util.py3compat import *
+from Crypto.Hash.hashalgo import HashAlgo
 
 try:
     import hashlib
@@ -52,5 +49,47 @@ except ImportError:
     from Crypto.Hash import _SHA224
     hashFactory = _SHA224
 
-digest_size = 28
-block_size = 64
+class SHA224Hash(HashAlgo):
+    """Class that implements a SHA-224 hash
+    
+    :undocumented: block_size
+    """
+
+    #: ASN.1 Object identifier (OID)::
+    #:
+    #:  id-sha224    OBJECT IDENTIFIER ::= {
+    #:      joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3)
+    #:      nistalgorithm(4) hashalgs(2) 4
+    #:  }
+    #:
+    #: This value uniquely identifies the SHA-224 algorithm.
+    oid = b('\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x04')
+
+    digest_size = 28
+    block_size = 64
+
+    def __init__(self, data=None):
+        HashAlgo.__init__(self, hashFactory, data)
+
+    def new(self, data=None):
+        return SHA224Hash(data)
+
+def new(data=None):
+    """Return a fresh instance of the hash object.
+
+    :Parameters:
+       data : byte string
+        The very first chunk of the message to hash.
+        It is equivalent to an early call to `SHA224Hash.update()`.
+        Optional.
+
+    :Return: A `SHA224Hash` object
+    """
+    return SHA224Hash().new(data)
+
+#: The size of the resulting hash in bytes.
+digest_size = SHA224Hash.digest_size
+
+#: The internal block size of the hash algorithm in bytes.
+block_size = SHA224Hash.block_size
+