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Merge pull request #274 from restic/fix-documentation 

Documentation fixes
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Alexander Neumann 2015-08-22 23:07:31 +02:00
parent 3f3cca8f2a 3a50c2bbfb
commit b188217e83
1 changed files with 16 additions and 17 deletions
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doc/Design.md
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@ -12,7 +12,7 @@ several subdirectories. A repository implementation must be able to fulfill a
number of operations, e.g. list the contents.
*Blob*: A Blob combines a number of data bytes with identifying information
like the SHA256 hash of the data and its length.
like the SHA-256 hash of the data and its length.
*Pack*: A Pack combines one or more Blobs, e.g. in a single file.
@ -246,18 +246,18 @@ repository password. This is then used with `scrypt`, a key derivation function
bytes. The first 32 bytes are used as the encryption key (for AES-256) and the
last 32 bytes are used as the message authentication key (for Poly1305-AES).
These last 32 bytes are divided into a 16 byte AES key `k` followed by 16 bytes
of secret key `r`. They key `r` is then masked for use with Poly1305 (see the
of secret key `r`. The key `r` is then masked for use with Poly1305 (see the
paper for details).
This message authentication key is used to compute a MAC over the bytes contained
in the JSON field `data` (after removing the Base64 encoding and not including
the last 32 byte). If the password is incorrect or the key file has been
tampered with, the computed MAC will not match the last 16 bytes of the data,
and restic exits with an error. Otherwise, the data is decrypted with the
encryption key derived from `scrypt`. This yields a JSON document which
contains the master encryption and message authentication keys for this
repository (encoded in Base64). The command `restic cat masterkey` can be used
as follows to decrypt and pretty-print the master key:
Those message authentication keys (`k` and `r`) are used to compute a MAC over
the bytes contained in the JSON field `data` (after removing the Base64
encoding and not including the last 32 byte). If the password is incorrect or
the key file has been tampered with, the computed MAC will not match the last
16 bytes of the data, and restic exits with an error. Otherwise, the data is
decrypted with the encryption key derived from `scrypt`. This yields a JSON
document which contains the master encryption and message authentication keys
for this repository (encoded in Base64). The command `restic cat masterkey` can
be used as follows to decrypt and pretty-print the master key:
$ restic -r /tmp/restic-repo cat masterkey
{
@ -315,9 +315,8 @@ Trees and Data
--------------
A snapshot references a tree by the SHA-256 hash of the JSON string
representation of its contents. Trees are saved in a subdirectory of the
directory `trees`. The sub directory's name is the first two characters of the
filename the tree object is stored in.
representation of its contents. Trees and data are saved in pack files in a
subdirectory of the directory `data`.
The command `restic cat tree` can be used to inspect the tree referenced above:
@ -462,10 +461,10 @@ General assumptions:
The restic backup program guarantees the following:
* Accessing the unencrypted content of stored files and meta data should not
* Accessing the unencrypted content of stored files and metadata should not
be possible without a password for the repository. Everything except the
`version` and `id` files and the meta data included for informational
purposes in the key files is encrypted and authenticated.
metadata included for informational purposes in the key files is encrypted and
authenticated.
* Modifications (intentional or unintentional) can be detected automatically
on several layers: