9.5 KiB
| title | description | lead | date | draft | images | menu | weight | toc | aliases | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Passwords | A reference guide on passwords and hashing etc | This section contains reference documentation for Authelia. | 2022-06-15T17:51:47+10:00 | false |
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220 | true |
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User / Password File
This file should be set with read/write permissions as it could be updated by users resetting their passwords.
YAML Format
The format of the YAML file is as follows:
users:
john:
disabled: false
displayname: "John Doe"
password: "$argon2id$v=19$m=65536,t=3,p=2$BpLnfgDsc2WD8F2q$o/vzA4myCqZZ36bUGsDY//8mKUYNZZaR0t4MFFSs+iM"
email: john.doe@authelia.com
groups:
- admins
- dev
harry:
disabled: false
displayname: "Harry Potter"
password: "$argon2id$v=19$m=65536,t=3,p=2$BpLnfgDsc2WD8F2q$o/vzA4myCqZZ36bUGsDY//8mKUYNZZaR0t4MFFSs+iM"
email: harry.potter@authelia.com
groups: []
bob:
disabled: false
displayname: "Bob Dylan"
password: "$argon2id$v=19$m=65536,t=3,p=2$BpLnfgDsc2WD8F2q$o/vzA4myCqZZ36bUGsDY//8mKUYNZZaR0t4MFFSs+iM"
email: bob.dylan@authelia.com
groups:
- dev
james:
disabled: false
displayname: "James Dean"
password: "$argon2id$v=19$m=65536,t=3,p=2$BpLnfgDsc2WD8F2q$o/vzA4myCqZZ36bUGsDY//8mKUYNZZaR0t4MFFSs+iM"
email: james.dean@authelia.com
Passwords
The file contains hashed passwords instead of plain text passwords for security reasons.
You can use Authelia binary or docker image to generate the hash of any password. The crypt hash generate command has
many supported algorithms. To view them run the authelia crypto hash generate --help command. To see the tunable
options for an algorithm subcommand include that command before --help. For example for the Argon2 algorithm use the
authelia crypto hash generate argon2 --help command to see the available options.
Passwords passed to crypt hash generate should be single quoted if using the --password parameter instead of the
console prompt, especially if it has special characters to prevent parameter substitution. For instance to generate an
Argon2 hash with the docker image just run:
$ docker run authelia/authelia:latest authelia crypto hash generate argon2 --password 'password'
Digest: $argon2id$v=19$m=65536,t=3,p=4$Hjc8e7WYcBFcJmEDUOsS9A$ozM7RyZR1EyDR8cuyVpDDfmLrGPGFgo5E2NNqRumui4
You may also use the --config flag to point to your existing configuration. When used, the values defined in the
config will be used instead. For example to generate the password with a configuration file named configuration.yml
in the current directory:
$ docker run -v ./configuration.yml:/configuration.yml -it authelia/authelia:latest authelia crypto hash generate --config /configuration.yml
Enter Password:
Confirm Password:
Digest: $argon2id$v=19$m=65536,t=3,p=4$Hjc8e7WYcBFcJmEDUOsS9A$ozM7RyZR1EyDR8cuyVpDDfmLrGPGFgo5E2NNqRumui4
See the full CLI reference documentation.
Cost
The most important part about choosing a password hashing function is the cost. It's generally recommended that the cost takes roughly 500 milliseconds on your hardware to complete, however if you have very old hardware you may want to consider more than 500 milliseconds, or if you have really high end hardware you may want to consider slightly less depending on if you have a large quantity of users.
Ideally on average hardware the amount of time would be roughly 500 milliseconds at minimum.
In consideration of your cost you should take into account the fact some algorithms only support scaling the cost for one factor and not others It's usually considered better to have a mix of cost types however this is not possible with all algorithms. The main cost type measurements are:
- CPU
- Memory
Important Note: When using algorithms that use a memory cost like Argon2 and Scrypt it should be noted that this memory is released by Go after the hashing process completes, however the operating system may not reclaim the memory until a later time such as when the system is experiencing memory pressure which may cause the appearance of more memory being in use than Authelia is actually actively using. Authelia will typically reuse this memory if it has not be reclaimed as long as another hashing calculation is not still utilizing it.
To get a rough estimate of how much memory should be utilized with these algorithms you can utilize the following command:
stress-ng --vm-bytes $(awk '/MemFree/{printf "%d\n", $2 * 0.9;}' < /proc/meminfo)k --vm-keep -m 1
If this is not desirable we recommend investigating the following options in order of most to least secure:
Algorithms
The default hash algorithm is the Argon2 id variant version 19 with a salt. Argon2 is at the time of this writing
widely considered to be the best hashing algorithm, and in 2015 won the Password Hashing Competition. It benefits from
customizable parameters including a memory parameter allowing the cost of computing a hash to scale into the
future with better hardware which makes it harder to brute-force.
For backwards compatibility and user choice support for the SHA2 Crypt algorithm (SHA512 variant) is still available.
While it's a reasonable hashing function given high enough iterations, as hardware improves it has a higher chance of
being brute-forced since it only allows scaling the CPU cost whereas Argon2 allows scaling both for CPU and
Memory cost.
Identification
The algorithm that a hash is utilizing is identifiable by its prefix:
| Algorithm | Variant | Prefix |
|---|---|---|
| Argon2 | argon2id |
$argon2id$ |
| Argon2 | argon2i |
$argon2i$ |
| Argon2 | argon2d |
$argon2d$ |
| Scrypt | N/A | $scrypt$ |
| PBKDF2 | sha1 |
$pbkdf2$ |
| PBKDF2 | sha224 |
$pbkdf2-sha224$ |
| PBKDF2 | sha256 |
$pbkdf2-sha256$ |
| PBKDF2 | sha384 |
$pbkdf2-sha384$ |
| PBKDF2 | sha512 |
$pbkdf2-sha512$ |
| SHA2 Crypt | SHA256 |
$5$ |
| SHA2 Crypt | SHA512 |
$6$ |
| Bcrypt | standard |
$2b$ |
| Bcrypt | sha256 |
$bcrypt-sha256$ |
See the Crypt (C) Wiki page for more information.
Tuning
The configuration variables are unique to the file authentication provider, thus they all exist in a key under the file authentication configuration key called password. The defaults are considered as sane for a reasonable system however we still recommend taking time to figure out the best values to adequately determine the cost.
While there are recommended parameters for each algorithm it's your responsibility to tune these individually for your particular system.
Algorithm Choice
We generally discourage Bcrypt except when needed for interoperability with legacy systems. The argon2id variant of
the Argon2 algorithm is the best choice of the algorithms available, but it's important to note that the argon2id
variant is the most resilient variant, followed by the argon2d variant and the argon2i variant not being recommended.
It's strongly recommended if you're unsure that you use argon2id. Scrypt is a likely second best algorithm. PBKDF2
is practically the only choice when it comes to FIPS-140 compliance. The sha512 variant of the SHA2 Crypt
algorithm is also a reasonable option, but is mainly available for backwards compatability.
All other algorithms and variants available exist only for interoperability and we discourage their use if a better algorithm is available in your scenario.
Recommended Parameters: Argon2
This table adapts the RFC9106 Parameter Choice recommendations to our configuration options:
| Situation | Variant | Iterations (t) | Parallelism (p) | Memory (m) | Salt Size | Key Size |
|---|---|---|---|---|---|---|
| Low Memory | argon2id | 3 | 4 | 65536 | 16 | 32 |
| Recommended | argon2id | 1 | 4 | 2097152 | 16 | 32 |
Recommended Parameters: SHA2 Crypt
This table suggests the parameters for the SHA2 Crypt algorithm:
| Situation | Variant | Iterations (rounds) | Salt Size |
|---|---|---|---|
| Standard CPU | sha512 | 50000 | 16 |
| High End CPU | sha512 | 150000 | 16 |