[ sf.net patch # 1121611 ]

A new hashlib module to replace the md5 and sha modules.  It adds
support for additional secure hashes such as SHA-256 and SHA-512.  The
hashlib module uses OpenSSL for fast platform optimized
implementations of algorithms when available.  The old md5 and sha
modules still exist as wrappers around hashlib to preserve backwards
compatibility.

1 files changed, 110 insertions, 0 deletions

diff --git a/Lib/hashlib.py b/Lib/hashlib.py
new file mode 100644
index 0000000..3528699
--- /dev/null
+++ b/Lib/hashlib.py
@@ -0,0 +1,110 @@
+# $Id$
+#
+#  Copyright (C) 2005   Gregory P. Smith (greg@electricrain.com)
+#  Licensed to PSF under a Contributor Agreement.
+#
+
+__doc__ = """hashlib module - A common interface to many hash functions.
+
+new(name, string='') - returns a new hash object implementing the
+                       given hash function; initializing the hash
+                       using the given string data.
+
+Named constructor functions are also available, these are much faster
+than using new():
+
+md5(), sha1(), sha224(), sha256(), sha384(), and sha512()
+
+More algorithms may be available on your platform but the above are
+guaranteed to exist.
+
+Choose your hash function wisely.  Some have known weaknesses.
+sha384 and sha512 will be slow on 32 bit platforms.
+"""
+
+
+def __get_builtin_constructor(name):
+    if name in ('SHA1', 'sha1'):
+        import _sha
+        return _sha.new
+    elif name in ('MD5', 'md5'):
+        import _md5
+        return _md5.new
+    elif name in ('SHA256', 'sha256', 'SHA224', 'sha224'):
+        import _sha256
+        bs = name[3:]
+        if bs == '256':
+            return _sha256.sha256
+        elif bs == '224':
+            return _sha256.sha224
+    elif name in ('SHA512', 'sha512', 'SHA384', 'sha384'):
+        import _sha512
+        bs = name[3:]
+        if bs == '512':
+            return _sha512.sha512
+        elif bs == '384':
+            return _sha512.sha384
+
+    raise ValueError, "unsupported hash type"
+
+
+def __py_new(name, string=''):
+    """new(name, string='') - Return a new hashing object using the named algorithm;
+    optionally initialized with a string.
+    """
+    return __get_builtin_constructor(name)(string)
+
+
+def __hash_new(name, string=''):
+    """new(name, string='') - Return a new hashing object using the named algorithm;
+    optionally initialized with a string.
+    """
+    try:
+        return _hashlib.new(name, string)
+    except ValueError:
+        # If the _hashlib module (OpenSSL) doesn't support the named
+        # hash, try using our builtin implementations.
+        # This allows for SHA224/256 and SHA384/512 support even though
+        # the OpenSSL library prior to 0.9.8 doesn't provide them.
+        return __get_builtin_constructor(name)(string)
+
+
+try:
+    import _hashlib
+    # use the wrapper of the C implementation
+    new = __hash_new
+
+    for opensslFuncName in filter(lambda n: n.startswith('openssl_'), dir(_hashlib)):
+        funcName = opensslFuncName[len('openssl_'):]
+        try:
+            # try them all, some may not work due to the OpenSSL
+            # version not supporting that algorithm.
+            f = getattr(_hashlib, opensslFuncName)
+            f()
+            # Use the C function directly (very fast)
+            exec funcName + ' = f'
+        except ValueError:
+            try:
+                # Use the builtin implementation directly (fast)
+                exec funcName + ' = __get_builtin_constructor(funcName)'
+            except ValueError:
+                # this one has no builtin implementation, don't define it
+                pass
+    # clean up our locals
+    del f
+    del opensslFuncName
+    del funcName
+
+except ImportError:
+    # We don't have the _hashlib OpenSSL module?
+    # use the built in legacy interfaces via a wrapper function
+    new = __py_new
+
+    # lookup the C function to use directly for the named constructors
+    md5 = __get_builtin_constructor('md5')
+    sha1 = __get_builtin_constructor('sha1')
+    sha224 = __get_builtin_constructor('sha224')
+    sha256 = __get_builtin_constructor('sha256')
+    sha384 = __get_builtin_constructor('sha384')
+    sha512 = __get_builtin_constructor('sha512')
+