Abstract: Aggregate signature algorithms allow multiple signatures to be compressed into a single signature, thereby improving the signature efficiency. The sequential aggregate signature algorithm based on the PSS (Probabilistic Signature Scheme) is a highly efficient and flexible signing scheme with the characteristics of reduced signature size, improved verification efficiency, and support for sequential processing; however, such schemes may face challenges in security guarantees and implementation complexity. This paper is based on the ISRSAC-PSS (Identity-based Sequential RSA with PSS) signature algorithm, employing identity-based and pseudorandom sequence generation techniques to propose a sequential aggregate signature algorithm. The proposed algorithm has features of efficient data compression, sequential processing capability, and enhanced security, and it can be proven to be secure under adaptive chosen plaintext attacks, maintaining good security. Comparative analysis shows that the proposed algorithm is nearly as efficient as aggregate signature schemes based on PSS with provable security and offers superior security.