A General Security Agreement (GSA) is a contract signed between a lender and a borrower to secure a loan with them.
In the GSA the lender lists all of the borrower's current tangible and intangible assets so they can use them as collateral and register a lien on everything through the Personal Property Securities Register(PPSR). In the contract, there is also a clause that allows them to have a lien on all future tangible & intangible assets until the loan is paid off.
Tangible assets include your real estate, equipment, inventory & machinery. Intangible assets include patents, trademarks, and intellectual property.
During the course of the loan, the borrower must perform the actions mentioned in the agreement and also get permission from the lender each time they want to sell their equipment or other assets. Most banks require a GSA when lending money.