Maryland Code, State Finance and Procurement § 17-104

(1) a bond executed by a surety company authorized to do business in the State;

(2) cash in an amount equivalent to a bond; or

(3) other security that is satisfactory to the public body awarding the contract.

(b)(1) Subject to paragraphs (2) and (3) of this subsection, performance security may include the granting of a mortgage or deed of trust on real property located within the State if such security is satisfactory to the public body awarding the contract.

(2) The face amount of a mortgage or deed of trust on real property granted as security under this subsection may not exceed 75% of the contractor's equity interest in the property.

(3) A mortgage or deed of trust accepted under this subsection shall be recorded by an official designated by the public body accepting the mortgage or deed of trust in the land records of the county where the real property is situated in accordance with § 3-103 of the Real Property Article.