A method for validating outsourced processing of a priority queue includes configuring a verifier for independent, single-pass processing of priority queue operations that include insertion operations and extraction operations and priorities associated with each operation. The verifier may be configured to validate N operations using a memory space having a size that is proportional to the square root of N using an algorithm to buffer the operations as a series of R epochs. Extractions associated with each individual epoch may be monitored using arrays Y and Z. Insertions for the epoch k may monitored using arrays X and Z. The processing of the priority queue operations may be verified based on the equality or inequality of the arrays X, Y, and Z. Hashed values for the arrays may be used to test their equality to conserve storage requirements.