* Encrypted repositories [not found] <fcbea7c0-b433-414b-abd3-b0e205a96fc5@zcs> @ 2012-09-06 2:23 ` Enrico Weigelt 2012-09-06 5:37 ` Junio C Hamano 0 siblings, 1 reply; 6+ messages in thread From: Enrico Weigelt @ 2012-09-06 2:23 UTC (permalink / raw) To: git Hi, I'm currently planning to implement an strong encryption in git (not like gitcrypt, but with encrypted blobs, directories, etc, directly in the core). The idea goes like this: * blobs are encrypted with their (original) content hash as encryption keys * directory objects only hold randomized filenames and pointers to the encrypted blob (content hash of the encrypted data) * new ext-directory objects are holding a mapping of the randomized file names to the real ones and the encryption keys, stored encrypted similar to the blobs * ext-directory object is referenced by a special filename in the directory object. * commit objects also hold an encrypted section (eg. uuencoded) with the ext-directory node's key, additional commit text, etc, itself encrypted with the repository key This way, the lowlevel / bare repository operations (including remote sync and gc) should continue to work, while only actual access (eg. checkout or commit) need to be changed and have the repository key available. What do you think about this approach ? cu -- Mit freundlichen Grüßen / Kind regards Enrico Weigelt VNC - Virtual Network Consult GmbH Head Of Development Pariser Platz 4a, D-10117 Berlin Tel.: +49 (30) 3464615-20 Fax: +49 (30) 3464615-59 enrico.weigelt@vnc.biz; www.vnc.de ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Encrypted repositories 2012-09-06 2:23 ` Encrypted repositories Enrico Weigelt @ 2012-09-06 5:37 ` Junio C Hamano 2012-09-06 13:56 ` Enrico Weigelt 0 siblings, 1 reply; 6+ messages in thread From: Junio C Hamano @ 2012-09-06 5:37 UTC (permalink / raw) To: Enrico Weigelt; +Cc: git Enrico Weigelt <enrico.weigelt@vnc.biz> writes: > * blobs are encrypted with their (original) content hash as > encryption keys What does this even mean? Is it expected that anybody who has access to the repository can learn names of objects (e.g. by running "ls .git/objects/??/")? If so, from whom are you protecting your repository? How does this encryption interact with delta compression employed in pack generation? ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Encrypted repositories 2012-09-06 5:37 ` Junio C Hamano @ 2012-09-06 13:56 ` Enrico Weigelt 2012-09-06 19:49 ` Junio C Hamano 0 siblings, 1 reply; 6+ messages in thread From: Enrico Weigelt @ 2012-09-06 13:56 UTC (permalink / raw) To: Junio C Hamano; +Cc: git Hi, > Enrico Weigelt <enrico.weigelt@vnc.biz> writes: > > > * blobs are encrypted with their (original) content hash as > > encryption keys > > What does this even mean? > > Is it expected that anybody who has access to the repository can > learn names of objects (e.g. by running "ls .git/objects/??/")? If > so, from whom are you protecting your repository? Well, everybody can access the objects, but they're encrypted, so you need the repo key (which, of course isn't contained in the repo itself ;-p) to decrypt them. The whole tree will still be consistent even without encryption support (so, gc etc shouldn't break), but to actually _use_ the repo (eg. checkout or adding new commits), you'll need the encryption support and the repo key (well, committing should theoretically even work with diffrent repo key, even this doesn't make much sense ;-)). > How does this encryption interact with delta compression employed > in pack generation? Probably not at all ;-o For the usecases I have in mind (backups, filesharing, etc) this wouldn't hurt so much, if the objects are compressed before encryption. cu -- Mit freundlichen Grüßen / Kind regards Enrico Weigelt VNC - Virtual Network Consult GmbH Head Of Development Pariser Platz 4a, D-10117 Berlin Tel.: +49 (30) 3464615-20 Fax: +49 (30) 3464615-59 enrico.weigelt@vnc.biz; www.vnc.de ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Encrypted repositories 2012-09-06 13:56 ` Enrico Weigelt @ 2012-09-06 19:49 ` Junio C Hamano 2012-09-08 3:34 ` Enrico Weigelt 0 siblings, 1 reply; 6+ messages in thread From: Junio C Hamano @ 2012-09-06 19:49 UTC (permalink / raw) To: Enrico Weigelt; +Cc: git Enrico Weigelt <enrico.weigelt@vnc.biz> writes: >> Enrico Weigelt <enrico.weigelt@vnc.biz> writes: >> >> > * blobs are encrypted with their (original) content hash as >> > encryption keys >> >> What does this even mean? >> >> Is it expected that anybody who has access to the repository can >> learn names of objects (e.g. by running "ls .git/objects/??/")? If >> so, from whom are you protecting your repository? > > Well, everybody can access the objects, but they're encrypted, > so you need the repo key (which, of course isn't contained in > the repo itself ;-p) to decrypt them. So, in short, blobs are not encrypted with the hash of their contents as encryption keys at all. >> How does this encryption interact with delta compression employed >> in pack generation? > > Probably not at all ;-o > > For the usecases I have in mind (backups, filesharing, etc) this > wouldn't hurt so much, if the objects are compressed before encryption. For that kind of usage pattern, you are better off looking at encrypted tarballs or zip archives. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Encrypted repositories 2012-09-06 19:49 ` Junio C Hamano @ 2012-09-08 3:34 ` Enrico Weigelt 2012-09-08 4:10 ` David Aguilar 0 siblings, 1 reply; 6+ messages in thread From: Enrico Weigelt @ 2012-09-08 3:34 UTC (permalink / raw) To: Junio C Hamano; +Cc: git > > Well, everybody can access the objects, but they're encrypted, > > so you need the repo key (which, of course isn't contained in > > the repo itself ;-p) to decrypt them. > > So, in short, blobs are not encrypted with the hash of their > contents as encryption keys at all. No, the blobs are encrypted with their content hash as key, and the encrypted blob will be stored with it's content hash as object id. > > For the usecases I have in mind (backups, filesharing, etc) this > > wouldn't hurt so much, if the objects are compressed before > > encryption. > > For that kind of usage pattern, you are better off looking at > encrypted tarballs or zip archives. No, that doesn't give us anything like history, incremental synchronization, etc, etc. What I finnaly wanna has is a usual git, just with encryption, but I can live with loosing differential compression. cu -- Mit freundlichen Grüßen / Kind regards Enrico Weigelt VNC - Virtual Network Consult GmbH Head Of Development Pariser Platz 4a, D-10117 Berlin Tel.: +49 (30) 3464615-20 Fax: +49 (30) 3464615-59 enrico.weigelt@vnc.biz; www.vnc.de ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Encrypted repositories 2012-09-08 3:34 ` Enrico Weigelt @ 2012-09-08 4:10 ` David Aguilar 0 siblings, 0 replies; 6+ messages in thread From: David Aguilar @ 2012-09-08 4:10 UTC (permalink / raw) To: Enrico Weigelt; +Cc: Junio C Hamano, git On Fri, Sep 7, 2012 at 8:34 PM, Enrico Weigelt <enrico.weigelt@vnc.biz> wrote: > >> > Well, everybody can access the objects, but they're encrypted, >> > so you need the repo key (which, of course isn't contained in >> > the repo itself ;-p) to decrypt them. >> >> So, in short, blobs are not encrypted with the hash of their >> contents as encryption keys at all. > > No, the blobs are encrypted with their content hash as key, and the > encrypted blob will be stored with it's content hash as object id. > >> > For the usecases I have in mind (backups, filesharing, etc) this >> > wouldn't hurt so much, if the objects are compressed before >> > encryption. >> >> For that kind of usage pattern, you are better off looking at >> encrypted tarballs or zip archives. > > No, that doesn't give us anything like history, incremental > synchronization, etc, etc. > > What I finnaly wanna has is a usual git, just with encryption, > but I can live with loosing differential compression. Something like this? https://gist.github.com/873637 I've never tried it myself, who knows if it works, but google found it when I searched for "git clean smudge filter encryption". I hope that helps, -- David ^ permalink raw reply [flat|nested] 6+ messages in thread
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[not found] <fcbea7c0-b433-414b-abd3-b0e205a96fc5@zcs>
2012-09-06 2:23 ` Encrypted repositories Enrico Weigelt
2012-09-06 5:37 ` Junio C Hamano
2012-09-06 13:56 ` Enrico Weigelt
2012-09-06 19:49 ` Junio C Hamano
2012-09-08 3:34 ` Enrico Weigelt
2012-09-08 4:10 ` David Aguilar
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