Toopher, based in Austin, Texas, it will no longer sell its current products, but is "thrilled to join Salesforce, where we'll work on delivering the Toopher vision on a much larger scale as part of the world's #1 Cloud Platform."
Financial terms of the acquisition were not disclosed.
Salesforce spokeswoman Karly Bolton confirmed the purchase but did not provide further details. Toopher's website is now inaccessible, except for the notice announcing the acquisition.
Toopher users had to download the app, available for iOS and Android, and pair it with the service. Users could automatically authenticate from safe locations like the home or work, but if the request came from a new or unrecognized location, the user received a notification from the Toopher app and could allow or deny the request.
"Toopher is the only solution that lets you automate that second step from safe locations like your home or office, so now you're only bothered when a login is out of the ordinary -- like when you're in a new location or being hacked," the firm wrote in its description of the app on iTunes and Google Play.
The University of Texas at Austin announced in July last year that it was adopting two-factor authentication using the regular electronic IDs login process and Toopher, saying it would provide an additional layer of security when users access sensitive applications.
Mobile security is likely to get increasingly important for Salesforce, particularly as it extends to newer devices the ability for users to run their businesses on the move. The company announced last month its Salesforce1 for Apple Watch, besides also offering on the device its mobile analytics platform and a developer pack for third-party developers to build enterprise apps that connect to the Salesforce1 platform.