RE: Literal packets and canonicalization

["Hasnain Mujtaba" <hmujtaba@xxxxxxxxxxxx>]

I understand that line endings need to be converted to CRLF. But what about trailing whitespace? When canonicalizing the literal data prior to encryption, do we have to strip off trailing whitespaces? From the RFC, it seems that for signatures the canonicalization must do both, i.e convert line endings and strip off trailing whitespaces. But I am not sure if the same needs to be done for encrypting text data.
 
Thanks

	-----Original Message----- 
	From: owner-ietf-openpgp@xxxxxxxxxxxx on behalf of David Shaw 
	Sent: Thu 5/6/2004 4:49 PM 
	To: ietf-openpgp@xxxxxxx 
	Cc: 
	Subject: Re: Literal packets and canonicalization
	
	


	On Thu, May 06, 2004 at 04:27:49PM -0400, Hasnain Mujtaba wrote:
	>
	> Thank you for the answer David. If, as the RFC states, we canoncialize
	> the data before storing it in the literal packet, then the
	> implementation is tampering with the file before performing the
	> operation, say encryption.
	
	"Tampering" is perhaps a little strong.  The canonicalization is part
	of the standard, so while it may be tampering, it's legal
	tampering. ;)
	
	> When I use GPG to encrypt and decrypt a text file, the checksums of
	> the source text file and the decrypted file are the same. So, the
	> file in not being canonicalized prior to encryption?
	
	Maybe, maybe not.  If you are encrypting and decrypting that text file
	on the same platform, then you would expect to end up with the same
	file since the data is canonicalized on the way in, and
	decanonicalized on the way out.
	
	Alternately, if you specified the text file as binary, then no
	canonicalization is done.
	
	GnuPG uses the "--textmode" switch to turn on canonicalization.  PGP
	has a checkbox for it named something like "Input is text".
	
	David