How to create custom Signature for Outbound Web Service calls

From Orlando release we can create our own Signature for Outbound web service if you don't want to use AWS signing This is the new feature from Orlando version

From Orlando 

N/A

* In order to use this feature, you need to active following plugins (may be already available in your instances)
com.glide.external.app
com.glide.external.app.api
com.snc.core.automation
com.glide.hub.integrations

* ihub.rest.step.generate.auth
This property is used to enable/disable outbound request signing feature. Default is true. If set to false, then it will not do the signing even credential is linked with auth_algorithm.

ihub.rest.step.awsv4.signing.expiry
This property is used to set the signature expiry, in seconds. If this is not set, default it is 300 seconds(5 mins). This means the signature will only valid for 5 mins.

* sys_script_include (for Glide instance and available OOB, you can use RequestAuthInternal script include as a base Script include where you can extend that and insert your own Signature)
1.RequestAuthAWSV4Signer:
-Default script used for AWS signing.

2.RequestAuthInternal:
-Base script used for all signing, read-only.

3.RequestAuthTwitterSigner
-Script used for twitter signing.

ecc_agent_script_include(for MID server, if you want to use MID server then you need to pick these script includes from these tables and customize your own signature

1.RequestAuthAWSV4MIDSigner
Default script used for MID server AWS signing

2. RequestAuthInternal
Base script used for all MID server signing, read-only

3. RequestAuthTwitterSigner
-Script used for twitter signing, which use glide for actual signing

* Here is the table you can create your own "auth_algorithm" click new to create new Algorithm and select "Algorithm" as Custom Authentication over there you have an option to select the Script includes you created with custom signature, either MID server script include or Instance script include

* Then you can refer those Algorithms in connections as attached in screen shot which you can use in flow.

* Please follow below documentation on how you can create the custom Signature for Outbound REST requests
https://docs.servicenow.com/csh?topicname=configure-authentication-algorithm.html&version=latest

https://docs.servicenow.com/csh?topicname=HttpRequestAuthedDataAPI.html&version=latest

* Here is Developer site where you can take some references for your customization
https://developer.servicenow.com/dev.do#!/reference/api/orlando/server/sn_auth-namespace/HttpRequestDataAPI