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Sadako
Advocate
Joined: 05 Aug 2004
Posts: 3792
Location: sleeping in the bathtub
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 Posted: Fri Jan 18, 2008 1:07 am Post subject: |
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| nielchiano wrote: | I'm no LUKS expert either, but according to the info I read, LUKS is acting more like a "header" It occupies the first N blocks of the partition. The crypto-data starts at sector N+1.
You can check that by creating a non-LUKS cryptomap and compare the offsets in dmtable:
| Code: | | loopcrypto: 0 20480 crypt aes-cbc-plain XXXXXXXX 0 7:0 0 |
| Code: | | loopcryptoLUKS: 0 19448 crypt aes-cbc-essiv:sha256 XXXXXXXX 0 7:0 1032 |
(format is documented here: http://www.saout.de/misc/dm-crypt/)
You can see that the luks-partition is offset by 1032 sectors from the beginning. In other words: the first 1032 sectors contain the LUKS header specifying the different keys that can be used to unlock the partition.
The (encrypted) filesystem doesn't even SEE the LUKS-data, just like it doesn't see the previous partition of the disk.
so this is correct: | depontius wrote: | | then LUKS is essentially a "container partition", meaning it sits *raw* inside a partition, and then itself acts like a partition to the filesystem it's hosting |
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Now why can't I ever expalin things that clearly?
This is what I came up with to try to create a picture of the layout; | Code: | | ( physical disk ( partition ( ( luks header ) ( dmcrypt mapping ( filesystem ) ) ) ) ) |
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wesw02
Apprentice
Joined: 10 Nov 2004
Posts: 213
Location: Dayton, Ohio, USA
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| Posted: Sun Apr 06, 2008 7:38 pm Post subject: Disadvantages of encrypting a partition |
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I'm extremely new to hard drive encryption, infact this article is only the second one I've read on the subject. I'm curious what are the disadvantages of encrypting your partition. I would imagine that read/write would be slowed a bit due to the overhead of encrypting and decrypting the data, but are there any others?
Edit: Also, what is the disadvantage of increasing the key-size, does it just slow down read/write the large the key-size? What is an ideal key-size to protect my data? Does it depend on the cipher I choose? |
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TBH the lolmaker
n00b
Joined: 01 Feb 2006
Posts: 64
Location: Poland
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| Posted: Sun Apr 06, 2008 9:01 pm Post subject: |
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Recently someone ran a test about efficiency of ecrypted filesystem, it was veeeeeeery little difference, I can confirm that 
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