Apache HTTP Server Version 2.3

Apache > HTTP Server > Documentation > Version 2.3 > Modules

# Apache Module mod_session_crypto

Available Languages: en

Description: | Session encryption support
Status: | Experimental
Module Identifier: | session_crypto_module
Source File: | mod_session_crypto.c
Compatibility: | Available in Apache 2.3 and later

### Summary

### Warning

The session modules make use of HTTP cookies, and as such can fall victim to Cross Site Scripting attacks, or expose potentially private information to clients. Please ensure that the relevant risks have been taken into account before enabling the session functionality on your server.

This submodule of `mod_session` provides support for the encryption of user sessions before being written to a local database, or written to a remote browser via an HTTP cookie.

This can help provide privacy to user sessions where the contents of the session should be kept private from the user, or where protection is needed against the effects of cross site scripting attacks.

For more details on the session interface, see the documentation for the `mod_session` module.

### Directives

### Topics

- Basic Usage

### See also

- `mod_session`
- `mod_session_cookie`
- `mod_session_dbd`

## Basic Usage

To create a simple encrypted session and store it in a cookie called session, configure the session as follows:

### Browser based encrypted session

`Session On
SessionCookieName session path=/
SessionCryptoPassphrase secret`

The session will be encrypted with the given key. Different servers can be configured to share sessions by ensuring the same encryption key is used on each server.

If the encryption key is changed, sessions will be invalidated automatically.

For documentation on how the session can be used to store username and password details, see the `mod_auth_form` module.

## SessionCryptoDriver Directive

Description: | The crypto driver to be used to encrypt the session
Syntax: | `SessionCryptoDriver name [param[=value]]`
Default: | `none`
Context: | server config
Status: | Experimental
Module: | mod_session_crypto
Compatibility: | Available in Apache 2.3.0 and later

The `SessionCryptoDriver` directive specifies the name of the crypto driver to be used for encryption. If not specified, the driver defaults to the recommended driver compiled into APR-util.

The NSS crypto driver requires some parameters for configuration, which are specified as parameters with optional values after the driver name.

### NSS without a certificate database

`SessionCryptoDriver nss`

### NSS with certificate database

`SessionCryptoDriver nss dir=certs`

### NSS with certificate database and parameters

`SessionCryptoDriver nss dir=certs key3=key3.db cert7=cert7.db secmod=secmod`

The NSS crypto driver might have already been configured by another part of the server, for example from `mod_nss` or `mod_ldap`. If found to have already been configured, a warning will be logged, and the existing configuration will have taken affect. To avoid this warning, use the noinit parameter as follows.

### NSS with certificate database

`SessionCryptoDriver nss noinit`

To prevent confusion, ensure that all modules requiring NSS are configured with identical parameters.

## SessionCryptoPassphrase Directive

Description: | The key used to encrypt the session
Syntax: | `SessionCryptoPassphrase secret`
Default: | `none`
Context: | server config, virtual host, directory, .htaccess
Status: | Experimental
Module: | mod_session_crypto
Compatibility: | Available in Apache 2.3.0 and later

The `SessionCryptoPassphrase` directive specifies the key to be used to enable symmetrical encryption on the contents of the session before writing the session, or decrypting the contents of the session after reading the session.

Keys are more secure when they are long, and consist of truly random characters. Changing the key on a server has the effect of invalidating all existing sessions.

The cipher can be set to 3des192 or aes256 using the cipher parameter as per the example below. If not set, the cipher defaults to aes256.

### Cipher

`SessionCryptoPassphrase secret cipher=aes256`

The openssl crypto driver supports an optional parameter to specify the engine to be used for encryption.

### OpenSSL with engine support

`SessionCryptoPassphrase secret engine=name`

Available Languages: en