I have previously blogged about how to create a LTPA session cookie for Lotus Domino and now I am finally able to present the code for creating this LTPA cookie that can be implemented on the F5 BIG-IP platform using the F5 iRules Control Language (which builds upon the Tcl scripting language). I created the code by going through a Java library for creating a LTPA cooke created by Miha Vitorovič.

The F5 iRule code is available for you to download – you just need to add the code necessary to do authentication of the user. Check F5 DevCentral for examples on this – for instance this iRule example that does reverse proxy with basic SSO.

Update: Based on this blog post I have created an article on this in the Lotus Notes & Domino wiki per request from Joyce Davis.

The following shows the actual code:

when RULE_INIT {
 set cookie_name "LtpaToken"           # Don't change this
 set ltpa_version "\x00\x01\x02\x03"   # Don't change this
 set ltpa_secret "b64encodedsecretkey" # Set this to the LTPA secrey key from your Lotus Domino LTPA configuration
 set ltpa_timeout "1800"               # Set this to the timeout value from your Lotus Domino LTPA configuration
}

when HTTP_REQUEST {
 #
 # Do your usual F5 HTTP authentication here
 #

 # Initial values
 set creation_time_temp [clock seconds]
 set creation_time [format %X $creation_time_temp]
 set expr_time_temp [expr { $creation_time_temp + $::ltpa_timeout}]
 set expr_time [format %X $expr_time_temp]
 set username [HTTP::username]
 set ltpa_secret_decode [b64decode $::ltpa_secret]

 # First part of token
 set cookie_data_raw {}
 append cookie_data_raw $::ltpa_version
 append cookie_data_raw $creation_time
 append cookie_data_raw $expr_time
 append cookie_data_raw $username
 append cookie_data_raw $ltpa_secret_decode

 # SHA1 of first part of token
 set sha_cookie_raw [sha1 $cookie_data_raw]

 # Final not yet encoded token
 set ltpa_token_raw {}
 append ltpa_token_raw $::ltpa_version
 append ltpa_token_raw $creation_time
 append ltpa_token_raw $expr_time
 append ltpa_token_raw $username
 append ltpa_token_raw $sha_cookie_raw

 # Final Base64 encoded token
 set ltpa_token_final [b64encode $ltpa_token_raw]

 # Insert the cookie
 HTTP::cookie insert name $::cookie_name value $ltpa_token_final
 }

 # Remove Authorization HTTP header to avoid using basic authentication
 if { [HTTP::header exists "Authorization"] } {
 HTTP::header remove "Authorization"
 }
}