Re: New crypto in 2.3.4

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Denis Corbin wrote:

[...]

>> Denis Corbin wrote:
>>> I don't neither, even if the crypto algorithm used was not perfect.
>>> Another solution is to keep the original algorithm beside the new and
>>> lable the old algorithm "wbf" (or "weak-blowfish"). Thus, having the
>>> real blowfish "bf" available in the resulting binary based on the
>>> presence of theses offending headers.
>> This would be a nice solution, since it would allow "strong blowfish"
>> versions of dar to still produce "weak blowfish" archives, if
>> compatibility with weak blowfish versions of dar was desired.
> 
> This is also a not too complicated solution.
> 
> note that actually, dar-2.3.4 is able to read encrypted archive
> generated with older version of dar.
> 

Well, here what is done in CVS and what will be available with release
2.3.5 about this issue:

dar compiles with or without the headers files openssl/evp.h and
openssl/hmac.h. If they are missing the new blowfish implementation will
not be available only the old implementation will be available. If they
are present both new and old implementation will be present.

bf or blowfish stay for the new implementation
bfw or blowfish_weak design the old implementation weakened by frequent
IV collision.

For backward compatibility, based on the archive revision (an archive
internal number that defines the archive format) dar will apply bfw
decryption if the archive has been generated by a dar version older than
2.3.4 even if the user specified 'bf' cipher. For archive generated by
more recent version (>= 2.3.4) bf and bfw are two different algorithms
and thus cannot be used interchangably.

the summary at then end of what the configure script produces as well as
'dar -V' let the user know whether the new blowfish encryption is
available or not as well as whether strong encryption is available at
all or not.

> 
>> Dave
> 
> 

Regards,
Denis.
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