How to deactivate security token to be enter?

Refer:
Avoid security token to enter

how to lock a record?

To lock a set of sObject records in Apex, embed the keywords FOR UPDATE after any inline SOQL statement

Difference between SOAP and Restful Webservice

* REST and SOAP are the two web service frameworks available on the Force.com platform. 
* The SOAP API uses authentication with username and password, and communicates using XML messages. There are different API's to work with the Enterprise, Partner, Bulk, Metadata etc. 
*The REST API uses HTTP to authenticate, it uses a token authentication and can use OATH to authenticate, it communicates using JSON messages. 
*REST API is generally lighter weight than the SOAP API, works well with mobile applications especially.