Re: Compression used in an encrypted message
Thank you for the explanations, everone. --Avi On 3/11/11, David Shaw wrote: > On Mar 11, 2011, at 2:01 PM, Avi wrote: > >> Thanks, everyone. >> >> So we can see the algorithm, but can not be able to see the compression >> level used, correct? > > Not directly, no. OpenPGP just encapsulates the compressed stream, so you'd > have to extract the compressed data and examine it. I'm not sure if a > single-number answer is available even then. Basically, if you can get the > level from a regular compressed .gz or .bz2 file, then you can get it here, > but either way, GPG does not have visibility into that. > > David > > -- Sent from my mobile device User:Avraham pub 3072D/F80E29F9 1/30/2009 Avi (Wikimedia-related key) Primary key fingerprint: 167C 063F 7981 A1F6 71EC ABAA 0D62 B019 F80E 29F9 ___ Gnupg-users mailing list Gnupg-users@gnupg.org http://lists.gnupg.org/mailman/listinfo/gnupg-users
Re: Compression used in an encrypted message
On Mar 11, 2011, at 2:01 PM, Avi wrote: > Thanks, everyone. > > So we can see the algorithm, but can not be able to see the compression level > used, correct? Not directly, no. OpenPGP just encapsulates the compressed stream, so you'd have to extract the compressed data and examine it. I'm not sure if a single-number answer is available even then. Basically, if you can get the level from a regular compressed .gz or .bz2 file, then you can get it here, but either way, GPG does not have visibility into that. David ___ Gnupg-users mailing list Gnupg-users@gnupg.org http://lists.gnupg.org/mailman/listinfo/gnupg-users
Re: Compression used in an encrypted message
Thanks, everyone. So we can see the algorithm, but can not be able to see the compression level used, correct? Thanks, --Avi User:Avraham pub 3072D/F80E29F9 1/30/2009 Avi (Wikimedia-related key) Primary key fingerprint: 167C 063F 7981 A1F6 71EC ABAA 0D62 B019 F80E 29F9 On Fri, Mar 11, 2011 at 1:35 PM, David Shaw wrote: > On Mar 11, 2011, at 12:50 PM, Avi wrote: > > > Forgive my ignorance, but is there a way to take a given > > encrypted message/file and determine which compression algorithm > > was used (and which level)? I know how to set compression > > algorithm and level prefs, but I'm curious to see what others > > use, if possible. > > You can't tell which compression is used in any arbitrary message since you > need to be able to decrypt it first. If the message is to you, however, you > can run 'gpg --list-packets' on it. > > When running list-packets, you should see a line like this: > > :compressed packet: algo=2 > > Algo 1 == ZIP > Algo 2 == ZLIB > Algo 3 == BZIP2 > > If there is no "compressed packet" line at all, then the message is > uncompressed. > > David > > ___ Gnupg-users mailing list Gnupg-users@gnupg.org http://lists.gnupg.org/mailman/listinfo/gnupg-users
Re: Compression used in an encrypted message
On Mar 11, 2011, at 12:50 PM, Avi wrote: > Forgive my ignorance, but is there a way to take a given > encrypted message/file and determine which compression algorithm > was used (and which level)? I know how to set compression > algorithm and level prefs, but I'm curious to see what others > use, if possible. You can't tell which compression is used in any arbitrary message since you need to be able to decrypt it first. If the message is to you, however, you can run 'gpg --list-packets' on it. When running list-packets, you should see a line like this: :compressed packet: algo=2 Algo 1 == ZIP Algo 2 == ZLIB Algo 3 == BZIP2 If there is no "compressed packet" line at all, then the message is uncompressed. David ___ Gnupg-users mailing list Gnupg-users@gnupg.org http://lists.gnupg.org/mailman/listinfo/gnupg-users
Re: Compression used in an encrypted message
On Fri, Mar 11, 2011 at 12:50:26PM -0500, Avi wrote: > -BEGIN PGP SIGNED MESSAGE- > Hash: SHA512 > > Forgive my ignorance, but is there a way to take a given > encrypted message/file and determine which compression algorithm > was used (and which level)? I know how to set compression > algorithm and level prefs, but I'm curious to see what others > use, if possible. If the file has been encrypted to you (or, more specifically, to one of the secret keys currently accessible to you), then, yes, you most probably can - "gpg --list-packets filename" should tell you what compression algorithm has been used, then it's just a matter of looking it up in RFC 4880 :) If the message has been encrypted to someone else's key, then you most probably won't be able to examine it - at least GnuPG does the compression before the encryption, so that the information about the compression algorithm used is contained within the encrypted data. You may still give it a shot with --list-packets, but don't expect too much :) Hope that helps. G'luck, Peter -- Peter Pentchev r...@ringlet.net r...@freebsd.org pe...@packetscale.com PGP key:http://people.FreeBSD.org/~roam/roam.key.asc Key fingerprint FDBA FD79 C26F 3C51 C95E DF9E ED18 B68D 1619 4553 This sentence contains exactly threee erors. signature.asc Description: Digital signature ___ Gnupg-users mailing list Gnupg-users@gnupg.org http://lists.gnupg.org/mailman/listinfo/gnupg-users
Compression used in an encrypted message
-BEGIN PGP SIGNED MESSAGE- Hash: SHA512 Forgive my ignorance, but is there a way to take a given encrypted message/file and determine which compression algorithm was used (and which level)? I know how to set compression algorithm and level prefs, but I'm curious to see what others use, if possible. Thanks, Avi -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.11 (MingW32) - GPGshell v3.77 Comment: Most recent key: Click show in box @ http://is.gd/4xJrs iJgEAREKAEAFAk16YNE5GGh0dHA6Ly9wZ3AubmljLmFkLmpwL3Brcy9sb29rdXA/ b3A9Z2V0JnNlYXJjaD0weEY4MEUyOUY5AAoJEA1isBn4Din5uvUA/2qqX7JAcw1C 36V3m9rSWMTt96xQeK6l+/abhwgb7Z6kAQCK0kPjBRiFromrcBueppwKKcvA6Rmw gO/pjOJhkKxMWQ== =kVV4 -END PGP SIGNATURE- User:Avraham pub 3072D/F80E29F9 1/30/2009 Avi (Wikimedia-related key) Primary key fingerprint: 167C 063F 7981 A1F6 71EC ABAA 0D62 B019 F80E 29F9 ___ Gnupg-users mailing list Gnupg-users@gnupg.org http://lists.gnupg.org/mailman/listinfo/gnupg-users
