SSN is an abridgment for Submersible Ship Nuclear, whereas SSBN stands for Submersible Ship Ballistic Missile Nuclear. Both attack submarines; however, the difference is the designs and primary functions. Submarines are considered to be a significant source of strength. SSBN carries a mixed bag of ammunition which includes the Tomahawk cruise missile. It is a killer in the submarine world. In WWII, SSBN was considered the most reliable ship due to its ability to survive a nuclear attack from the United States.
The SSN is a nuclear- powered general all-purpose attack submarine. It was used as a classification symbol. Another purpose of the SSN is to carry cruise missiles with explosives, which are used to attack assailants within the shores. SSN's were also used to conduct surveillance, perform complete intelligence missions, and aid in highly classified operations