[Jython-bugs] [ jython-Bugs-1599004 ] SHA module produces incorrect results

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Bugs item #1599004, was opened at 2006-11-18 17:22
Message generated for change (Comment added) made by cgroves
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Category: Library
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: A.M. Kuchling (akuchling)
Assigned to: Nobody/Anonymous (nobody)
Summary: SHA module produces incorrect results

Initial Comment:
test_hmac and test_pep247 fail because of problems with the SHA module.

* SHA and MD5 objects lack a .digest_size attribute.

* Successive calls to digest() return different values.

* For digest(), the byte array is converted to a string using the default encoding, which produces weird results if it's UTF-8.  It should hardwire using ISO-8859-1, because we want a 1-to-1 mapping of characters.

The attached patch fixes test_pep247.  test_hmac still fails; I'm still looking into the problem.


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>Comment By: Charles Groves (cgroves)
Date: 2006-11-20 14:37

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I only see one problem in these changes: calling String.getBytes with
ISO-8859-1 uses CodingErrorAction.REPLACE in its internal CharsetEncoder. 
That just replaces characters above 255 with '?'.  I think we want it to
throw an exception, right?

Unfortunately, CharsetEncoder appeared in Java 1.4 so we can't just use it
directly for 2.2. As far as I can tell, there's no way in versions earlier
than 1.4 to get that kind of control over the encoding in Java's library. 
We may have to write a bit of code in PyString or the like that handles
converting Strings to bytes and reports errors instead of eating them. 
This applies to http://jython.org/bugs/1599900 as well.

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Comment By: A.M. Kuchling (akuchling)
Date: 2006-11-19 13:45

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Revised version of the patch against the trunk; this now fixes test_hmac. 
The problem was the use of .getBytes(), which uses a system-specific
encoding; here we need it to use ISO-8859-1.


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