Security

Encryption

ASF currently supports the following encryption methods as a definition of ECryptoMethod:

Value	Name
0	PlainText
1	AES
2	ProtectedDataForCurrentUser
3	EnvironmentVariable
4	File

The exact description and comparison of them is available below.

In order to generate encrypted password, e.g. for SteamPassword usage, you should execute encrypt command with the appropriate encryption that you chose and your original plain-text password. Afterwards, put the encrypted string that you've got as SteamPassword bot config property, and finally change PasswordFormat to the one that matches your chosen encryption method. Some formats do not require encrypt command, for example EnvironmentVariable or File, just put appropriate path for them.

`PlainText`

This is the most simple and insecure way of storing a password, defined as ECryptoMethod of 0. ASF expects the string to be a plain text - a password in its direct form. It's the easiest one to use, and 100% compatible with all the setups, therefore it's a default way of storing secrets, totally insecure for safe storage.

`AES`

Considered secure by today standards, AES way of storing the password is defined as ECryptoMethod of 1. ASF expects the string to be a base64-encoded sequence of characters resulting in AES-encrypted byte array after translation, which then should be decrypted using included initialization vector and ASF encryption key.

The method above guarantees security as long as attacker doesn't know ASF encryption key which is being used for decryption as well as encryption of passwords. ASF allows you to specify key via --cryptkey command-line argument, which you should use for maximum security. If you decide to omit it, ASF will use its own key which is known and hardcoded into the application, meaning anybody can reverse the ASF encryption and get decrypted password. It still requires some effort and is not that easy to do, but possible, that's why you should almost always use AES encryption with your own --cryptkey which is kept in secret. AES method used in ASF provides security that should be satisfying and it's a balance between simplicity of PlainText and complexity of ProtectedDataForCurrentUser, but it's highly recommended to use it with custom --cryptkey. If used properly, guarantees decent security for safe storage.

`ProtectedDataForCurrentUser`

Currently the most secure way of encrypting the password that ASF offers, and much safer than AES method explained above, is defined as ECryptoMethod of 2. The major advantage of this method is at the same time the major disadvantage - instead of using encryption key (like in AES), data is encrypted using login credentials of currently logged in user, which means that it's possible to decrypt the data only on the machine it was encrypted on, and in addition to that, only by the user who issued the encryption. This ensures that even if you send your entire Bot.json with encrypted SteamPassword using this method to somebody else, he will not be able to decrypt the password without direct access to your PC. This is excellent security measure, but at the same time has a major disadvantage of being least compatible, as the password encrypted using this method will be incompatible with any other user as well as machine - including your own if you decide to e.g. reinstall your operating system. Still, it's one of the best methods of storing passwords, and if you're worried about security of PlainText, and don't want to put password each time, then this is your best bet as long as you don't have to access your configs from any other machine than your own.

Please note that this option is available only for machines running Windows OS as of now.

`EnvironmentVariable`

Memory-based storage. ASF will read the password out of the environment variable with given name specified in the password field (e.g. SteamPassword). For example, setting SteamPassword to ASF_PASSWORD_MYACCOUNT and PasswordFormat to 3 will cause ASF to evaluate ${ASF_PASSWORD_MYACCOUNT} environment variable and use whatever is assigned to it as the account password.

`File`

File-based storage outside of the ASF config directory. ASF will read the password out of the file path specified in the password field (e.g. SteamPassword). The specified path can be either relative to ASF's location (the folder where the config directory is included, or the one specified by --path command-line argument), or absolute. This method can be used for example with Docker secrets, which create such files for usage, but can also be used outside of Docker if you create appropriate file yourself. Gentle reminder to ensure that file containing the password is not readable by unathorized users. For example, setting SteamPassword to /etc/secrets/MyAccount.pass and PasswordFormat to 4 will cause ASF to read /etc/secrets/MyAccount.pass and use whatever is written to that file as the account password.

Recommendation

If compatibility is not an issue for you, and you're fine with the way how ProtectedDataForCurrentUser method works, it is the recommended option of storing the password in ASF, as it provides the best security. AES method is a good choice for people who still want to make use of their configs on any machine they want, while PlainText is the most simple way of storing the password, if you don't mind that anybody can look into JSON configuration file for it.

Please keep in mind that all of those 3 methods are considered insecure if attacker has access to your PC. ASF must be able to decrypt the encrypted passwords, and if the program running on your machine is capable of doing that, then any other program running on the same machine will be capable of doing so, too. ProtectedDataForCurrentUser is the most secure variant as even other user using the same PC will not be able to decrypt it, but it's still possible to decrypt the data if somebody is able to steal your login credentials and machine info in addition to ASF config file.

In addition to encryption methods specified above, it's possible to also avoid specifying passwords entirely, for example as SteamPassword by using an empty string or null value. ASF will ask you for your password when it's required, and won't save it anywhere but keep in memory of currently running process, until you close it. While being the most secure method of dealing with passwords (they're not saved anywhere), it's also the most troublesome as you need to enter your password manually on each ASF run (when it's required). If that's not a problem for you, this is your best bet security-wise.

Decryption

ASF doesn't support any way of decrypting already encrypted passwords, as decryption methods are used only internally for accessing the data inside the process. If you want to revert encryption procedure e.g. for moving ASF to other machine when using ProtectedDataForCurrentUser, then simply repeat the procedure from beginning in the new environment.

Hashing

ASF currently supports the following hashing methods as a definition of EHashingMethod:

Value	Name
0	PlainText
1	SCrypt
2	Pbkdf2

The exact description and comparison of them is available below.

In order to generate a hash, e.g. for IPCPassword usage, you should execute hash command with the appropriate hashing method that you chose and your original plain-text password. Afterwards, put the hashed string that you've got as IPCPassword ASF config property, and finally change IPCPasswordFormat to the one that matches your chosen hashing method.

`PlainText`

This is the most simple and insecure way of hashing a password, defined as EHashingMethod of 0. ASF will generate hash matching the original input. It's the easiest one to use, and 100% compatible with all the setups, therefore it's a default way of storing secrets, totally insecure for safe storage.

`SCrypt`

Considered secure by today standards, SCrypt way of hashing the password is defined as EHashingMethod of 1. ASF will use the SCrypt implementation using 8 blocks, 8192 iterations, 32 hash length and encryption key as a salt to generate the array of bytes. The resulting bytes will then be encoded as base64 string.

ASF allows you to specify salt for this method via --cryptkey command-line argument, which you should use for maximum security. If you decide to omit it, ASF will use its own key which is known and hardcoded into the application, meaning hashing will be less secure. If used properly, guarantees decent security for safe storage.

`Pbkdf2`

Considered weak by today standards, Pbkdf2 way of hashing the password is defined as EHashingMethod of 2. ASF will use the Pbkdf2 implementation using 10000 iterations, 32 hash length and encryption key as a salt, with SHA-256 as a hmac algorithm to generate the array of bytes. The resulting bytes will then be encoded as base64 string.

ASF allows you to specify salt for this method via --cryptkey command-line argument, which you should use for maximum security. If you decide to omit it, ASF will use its own key which is known and hardcoded into the application, meaning hashing will be less secure.

Recommendation

If you'd like to use a hashing method for storing some secrets, such as IPCPassword, we recommend to use SCrypt with custom salt, as it provides a very decent security against brute-forcing attempts. Pbkdf2 is offered only for compatibility reasons, mainly because we already have a working (and needed) implementation of it for other use cases across Steam platform (e.g. parental pins). It's still considered secure, but weak compared to alternatives (e.g. SCrypt).