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from the resistance-is-futile.-/home-will-be-assimilated dept.
Good News:
Linux home directory management is about to undergo major change:
With systemd 245 comes systemd-homed. Along with that, Linux admins will have to change the way they manage users and users' home directories.
[...] Prior to systemd every system and resource was managed by its own tool, which was clumsy and inefficient. Now? Controlling and managing systems on Linux is incredibly easy.
But one of the creators, Leannart Poettering, has always considered systemd to be incomplete. With the upcoming release of systemd 245, Poettering will take his system one step closer to completion. That step is by way of homed.
[...] let's take a look at the /home directory. This is a crucial directory in the Linux filesystem hierarchy, as it contains all user data and configurations. For some admins, this directory is so important, it is often placed on a separate partition or drive than the operating system. By doing this, user data is safe, even if the operating system were to implode.
However, the way /home is handled within the operating system makes migrating the /home directory not nearly as easy as it should be. Why? With the current iteration of systemd, user information (such as ID, full name, home directory, and shell) is stored in /etc/passwd and the password associated with that user is stored in /etc/shadow. The /etc/passwd file can be viewed by anyone, whereas /etc/shadow can only be viewed by those with admin or sudo privileges.
[...] Poettering has decided to make a drastic change. That change is homed. With homed, all information will be placed in a cryptographically signed JSON record for each user. That record will contain all user information such as username, group membership, and password hashes.
Each user home directory will be linked as LUKS-encrypted containers, with the encryption directly coupled to user login. Once systemd-homed detects a user has logged in, the associated home directory is decrypted. Once that user logs out, the home directory is automatically encrypted.
[...] Of course, such a major change doesn't come without its share of caveats. In the case of systemd-homed, that caveat comes by way of SSH. If a systemd-homed home directory is encrypted until a user successfully logs in, how will users be able to log in to a remote machine with SSH?
The big problem with that is the .ssh directory (where SSH stores known_hosts and authorized_keys) would be inaccessible while the user's home directory is encrypted. Of course Poettering knows of this shortcoming. To date, all of the work done with systemd-homed has been with the standard authentication process. You can be sure that Poettering will come up with a solution that takes SSH into consideration.
Older articles:
- Pack Your Bags – Systemd Is Taking You To A New Home
- Systemd-Homed Merged As A Fundamental Change To Linux Home Directories
Will systemd be considered complete once the kernel and boot loader have been absorbed into systemd?
(Score: 0) by Anonymous Coward on Saturday May 02 2020, @01:45PM (3 children)
You are over thinking it. You are trying to say the intent is what defines it, but the base function, remains the same: symbol replacement.
One of the best an easiest in encryption method is ZIP files, with a simple password. Why the "compression" function makes the texst unreadable and then add a simple xor over the space makes breaking very hard. But this gets down to simple again simple processes.
Take just the simple rotate encryption method and make a minor change. Start with a list of 256 characters filled so that element 00 is filled with x00, 01 is x01 and so on. Now look up each letter in the table and spit out the replacement address. Then move the found letter to the 00 position and shift others down. So EEGEG would be replaced with E,x00,G,x01,x01. You call that encryption. But is also a precursor to improve compression, since it heavily coverts a lot of text to a heavily weighted "left handed character steam, so it improves the compression algorithm. IF it outputs a number stream asc(E),0,asc(G),1,1 then we get down to 11 symbols to compress 0-9 and ",". Even better compression can be preformed. Just using the initial list the decoding will work in reverse. See Dr Jobbs from earily 80's.
Now make one more change the original list instead of seeding with x00,x01,x02. But a random string of non-repeating characters, using some "pass key". Then stream is not clear text readable. but the patterns are same, so all the other work just the same. all the other benefits are present highly compressible. Just without the "pass key" seed the list again, the stream is junk. But yes, you could make hundreds of runs crack it so the over all encryption is weak, but still encrypted.
I used this method in the 90's to improve storing signatures that had to be sent via cellular modem. Took a 70k "B&W" signature picture and compress to under 768 bytes. was very conversion on 386 table of day and quick send over modem (2400 baud), also fairly secure since 3 symbol replacements methods were used together transform the data giving both reduction in size and human readability.
So again the only difference between encryption and compression which are both symbol replacements is what is known and not known. Compression everything is known, starting key/pad/list and methodical. Encryption at least starting key/pad/list is not generally known.
(Score: 1) by khallow on Saturday May 02 2020, @03:58PM (2 children)
I'd say "succeeding at". You can abstract any human activity (just the phrase alone does it) to a level where you're not distinguishing the differences. But once you abstract enough that you lose track of why the activity happens, then you've gone too far.
Here, not only have you lost track of the differences between encryption and compression, you've conflated it with a bunch of other human activity. Such as the very generic activities of communication, translation, and recording/logging.
(Score: 0) by Anonymous Coward on Sunday May 03 2020, @12:07AM (1 child)
Another Trump ID-10T was just heard from. Scientists are liars. The world is flat. Get me my metal hat to keep the rats out.
Remember base learning.
A=B, C=B there for A=C Simple math.
Encryption is translation, Compression is translation, a translation is a translation, period. The only thing missing in one to but not in the other is the base key.
PS: Learned have used these facts, outside of Chicago, working inside a big circle. With real scientists that dealt with number theories and military encryption. That was their specialty. Its wonderful who you can meet and talk with for hours in the intersection between MENSA and LUGs.
(Score: 1) by khallow on Sunday May 03 2020, @12:15AM
Except, of course, when A!=B or C!=B. Simple math. The problem here is not simple math. It's the use of an equivalence relation that is too general.
Facts which were irrelevant to the thread!