This volume constitutes the proceedings of the 13th International Conference on post-quantum cryptography, PQCrypto 2022, held in as a Virtual Event in September 2022.The 23 full papers presented in this volume were carefully reviewed and selected from 66 submissions.

Code-Based Cryptography.- Hybrid Decoding - Classical-Quantum Trade-O s for Information Set Decoding.- How to Backdoor (Classic) McEliece and How to Guard Against Backdoors.- LRPC codes with multiple syndromes: near ideal-size KEMs without ideals.- Interleaved Prange: A New Generic Decoder for Interleaved Codes.- A Study of Error Floor Behavior in QC-MDPC Codes.- Multivariate Cryptography and the MinRank Problem.- Improvement of algebraic attacks for superdetermined MinRank.- A New Fault Attack on UOV Multivariate Signature Scheme.- MR-DSS - Smaller MinRank-based (Ring-)Signatures.- IPRainbow.- 2F - A New Method for Constructing E cient Multivariate Encryption Schemes.- Quantum Algorithms, Attacks and Models.- Quantum Attacks on Lai-Massey Structure.- Sponge-based Authenticated Encryption: Security against Quantum Attackers.- Post-quantum Plaintext-awareness.- On Quantum Ciphertext Indistinguishability, Recoverability, and OAEP.- Implementation and Side channel attacks.- Effciently Masking Polynomial Inversion at Arbitrary Order.- A Power Side-Channel Attack on the Reed-Muller Reed-Solomon Version of the HQC Cryptosystem.- A New Key Recovery Side-Channel Attack on HQC with Chosen Ciphertext.- Isogeny.- On Actively Secure Fine-Grained Access Structures from Isogeny Assumptions.- Attack on SHealS and HealS: the Second Wave of GPST.- Post-Quantum Signal Key Agreement from SIDH.- Lattice-Based Cryptography.- Forward-Secure Revocable Secret Handshakes from Lattices.- Estimating the Hidden Overheads in the BDGL Lattice Sieving Algorithm.- Cryptanalysis.- Breaking Category Five SPHINCS+ with SHA-256.