The contractor shall enter into a bond in such sum as may be fixed by the county commission, township board or district commissioners, with some surety company authorized to do business in this state as surety thereon or other good and sufficient surety, the condition of such bond to be that the contractor will faithfully discharge his duties under the contract within the time and in the manner therein provided, and that he will furnish and promptly pay for all labor employed and materials used and equipment rented in the performance of said contract, and the state, county or political subdivision, or any laborer, materialman or other person injured by breach of such contract may sue on such bond. All such bonds when approved by the proper authorities shall be recorded upon the proper records.