OX Guard 2.4+ Configuration

There are two main files for configuring OX Guard: guard-api.properties and guard-core.properties. The first configuration file is part of the OX backend and contains properties, among others, that enable the OX Guard functionality for various modules such as Mail and Drive as well as some capabilities. The second configuration file is part of the OX Guard and contains properties that configures the behaviour of the product.

Configuration File (guard-api.properties)

Main Properties

com.openexchange.capability.guard = true

Enables Guard. If not set, no guard functions will be loaded in the UI. Needed if users should be able to do ANY Guard functions including reading encrypted emails. This level will allow users without "guard-mail" enabled to read emails sent to them, reply to those emails, but not create new emails. Recommended minimum level for all users.

com.openexchange.capability.guard-mail = true

Enables the user(s) ability to send encrypted emails. If False but guard enabled, they can read encrypted emails and reply to the original sender, but they cannot compose new emails

com.openexchange.capability.guard-drive = true

Enables the drive functionality. If false, user(s) will not be able to decode nor upload new encrypted files

Optional Properties

com.openexchange.guard.templateID = 0

Define template customization ID for the Guest reader emails, the Guest reader, and system emails. See Customization for details.

com.openexchange.guard.endpoint =

Specifies the URI to the OX Guard end-point; e.g. http://guard.host.invalid:8009/guardadmin. By default is empty.


com.openexchange.capability.guard-pin = true

Enables optional PIN function when sending emails to non-OX users. Will provide an additional 4 digit pin that should be sent to the recipient. Extra protection during the time that the temporary password was assigned and sent.

com.openexchange.capability.guard-nodeleterecovery = true

(Guard 2.0) Disable the ability of the user to delete the recovery keys. Makes it impossible to reset password, but also adds level of protection/security

com.openexchange.capability.guard-nodeleteprivate = true

(Guard 2.0) Disable the ability of the user to delete their private key. They can revoke it, but not delete the key.

com.openexchange.capability.guard-nodeleteonrevoke = true

(Deprecated as of Guard 2.0) Default when revoking an item is to delete the content key, making the item impossible to decode. If this option is true, then the item is merely expired and can later be retrieved for decoding in case of legal requirements, corporate requirements, etc

com.openexchange.capability.guard-noextra = true

(Deprecated as of Guard 2.0) Disables the ability to add an extra password to encrypted items. May be required by some industry

Configuration File (guard-core.properties)


com.openexchange.guard.oxguardDatabaseHostname = localhost

The address of the MySQL database for OX Guard data. May be the same as the OX MySQL database.


Optional read-only IP/name for the OX Guard database that might be used in Master-Slave setups.


IP/Name for the location of the Guest database shards. Additional shards will be created on this database


Optional read-only IP/name for Guest database shards that might be used in Master-Slave setups.

com.openexchange.guard.databaseUsername = username

The username to access the OX Backend and Guard database. This user needs to have select, create, lock, insert, update privileges. Guard database user also should have alter (for updates), drop, index.

com.openexchange.guard.databasePassword = password

The password for the databases


com.openexchange.guard.restApiHostname = localhost

The address for the OX REST API. It would be the location of the OX Backend

com.openexchange.guard.OXBackendPort =  8009

The port for the OX Backend. Default is 8009 (which is direct communication with the backend). Could be 80, etc, if going through load balancers

com.openexchange.guard.restApiUsername = open-xchange com.openexchange.guard.restApiPassword = secret

Username and password for the REST API

com.openexchange.guard.externalEmailURL = example.com/appsuite/api/oxguard/reader/reader.html

When Guard sends an e-Mail to external recipients those recipients will be able to access the encrypted content by opening a link in that e-Mail. The description and the link of that e-Mail are not encrypted and always readable by the recipient. The link points to the Guard reader for external recipients, a servlet to decrypt and display the encrypted e-Mail content. Specify which domain and path should be used. The https link will be created dynamically by Guard. This value will be used as the default unless over-written by cascade value com.openexchange.guard.externalReaderURL.

Support API

com.openexchange.guard.supportapiusername = xxxxx
com.openexchange.guard.supportapipassword = yyyyy

If the support API is to be used, a username and password should be configured.

com.openexchange.guard.exposedKeyDurationInHours = 168

When a user is deleted, the Private keys are saved in a temporary deleted Keys table (in case of accidental deletion). If support "exposes" the key, the user can then retrieve it using link generated. For security reasons, this link is only valid for a short period of time. This property defines that duration.

File Storage

Local/remote storage is required for temporary caching of encrypted emails to guest/non-OX users. This can be an attached local file store, or Amazon S3 compatible object store depending on which open-xchange-guard-*-storage package is installed (file or S3).

General Properties

com.openexchange.guard.cacheDays = 30

How many days emails to guests are kept in file store before being deleted. Measured from time of sending, reset when someone reads the email. For this period a guest can access the mail directly via the provided link. If the cache is swiped though the mail will be removed from the server so the guest cannot directly read it anymore via the guest interface until he uploads the encrypted mail (received as attachment to the notification) within the guest UI for decrypted reading.

Storage Specific Properties

com.openexchange.guard.storage.file.uploadDirectory = /var/spool/open-xchange/guard/uploads

Defines the temporary upload and cache directory for OX Guard Drive files for open-xchange-guard-file-storage package. This directory needs to be shared between application servers serving the Guest Reader interface.

com.openexchange.guard.storage.s3.endpoint =
com.openexchange.guard.storage.s3.bucketName =
com.openexchange.guard.storage.s3.region =
com.openexchange.guard.storage.s3.accessKey =
com.openexchange.guard.storage.s3.secretKey =

S3 configuration options if the package open-xchange-guard-s3-storage is selected.


com.openexchange.guard.aesKeyLength=256 (Depreciated)

AES Key length. 256 is preferred, but not supported on all systems. May need to have the Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files installed.


RSA key length. Used when creating PGP keys


com.openexchange.guard.publicPGPDirectory = hkp://keys.gnupg.net:11371, hkp://pgp.mit.edu:11371

List of PGP Public key servers to query for public keys


A list of IP addresses of TRUSTED Guard servers. When the public PGP key server is queried, it will normally only find Guard keys that have already been created. If on the whitelist, the Guard server will also query the OX backend to see if the email address exists on the OX system, and if so, will create new keys for the user.

com.openexchange.guard.keyValidDays = 3650

PGP keys created will only be valid for this number of days. Default is 10 years. Set to 0 if no expiration date.


When looking up remote PGP keys, if found, the keys will be stored in a temporary cache. Set number of days until the cache item is expired and remote lookup is repeated.

com.openexchange.guard.usestarttls = true

Use TLS when delivering to the SMTP server when available



SMTP settings for outgoing emails from the guest reader. Emails sent from within the system use the OX Backend. The guest reader, however, sends replies through this SMTP. In addition, password emails (reset, initial) are sent through the SMTP server.

Bad Attempts

com.openexchange.guard.badMinuteLock = 10

Defines how long someone will be locked out after bad attempts. Defaults to 10 minutes.

com.openexchange.guard.badPasswordCount = 5

Defines how many times a person can attempt to unlock an encrypted item before being locked out. Defaults to 5 times.

RSA Key Generation

com.openexchange.guard.rsacache = true

RSA keys are pre-generated in the background, encrypted, and stored for future user keys. RSA key generation is the most time consuming function and the RSA cache significantly improves new user creation time.

com.openexchange.guard.rsacachecount = 100

Number of RSA keys to pre-generate

com.openexchange.guard.keycachecheckinterval = 30

Interval in seconds to check the RSA cache and re-populate if less than rsacachecount.

com.openexchange.guard.rsacertainty = 256

Bit certainty for RSA key generation. Higher numbers assure the number is in fact prime but time consuming. Lower is much faster. May need to be lower if not using cache.



Length of the randomly generated passwords when a user resets password.


Minimum password length.


com.openexchange.guard.oxbackendpath = /ajax/

URL used to communicated directly with the OX backend.

com.openexchange.guard.oxbackendidletime = 60

HTTP connections to the backend are kept open for faster response. This is the timeout setting that will close idle connections.

Guest Accounts


Guest users data are placed in databases oxguard_x. After set number of users, another database shard is created


Full path after domain name for the external reader (if changed from default)


If you do not want password recovery available, you can disable by adding

com.openexchange.guard.noRecovery = true

Keep in mind, that a lost password will result in total loss of encrypted data.


com.openexchange.guard.secureReply = true

(since Guard 2.2) Normally, when a person replies from an encrypted email, the reply is automatically encrypted. Set to false to disable this automatic encryption


Starting with 2.4.0, OX Guard is running inside the OSGi container, meaning that all its servlets are being registered and served by Grizzly.


com.openexchange.guard.backendSSL = false

Per default the connection between the Guard backend and the configured Open-Xchange REST API host is unencrypted. Even though that Guard will never transmit unencrypted emails to or from the REST API you can optionally encrypt the whole communication between those two components by using SSL. Please note: Enabling SSL might decrease performance and/or create more system load due to additional encoding of the HTTP streams.

Incoming SSL

The communication between the frontend load balancer (Apache or otherwise) to Guard is by default HTTP (if protected network). More information on how to enable SSL you can find here.