S3curePss

S3curePss is a cryptographic software library and reference implementation that provides signing and verification using the RSASSA-PSS signature scheme. It is designed to facilitate secure software distribution, document authentication, and PKI workflows, with an emphasis on portability and ease of integration across platforms and languages.

The core library is written in C, with bindings available for Python and Java. It implements RSA key generation and management, supports RSASSA-PSS signatures with hash functions including SHA-256, SHA-384, and SHA-512, and follows the PKCS #1 v2.1 specifications for EMSA-PSS padding. The API supports signing and verification operations, streaming data, and integration with hardware security modules through a pluggable RNG and key storage interface.

From a security and quality perspective, S3curePss emphasizes constant-time implementations for critical paths, thorough input validation, and secure memory handling with zeroization. The project provides a test suite, conformance tests, and documentation, and adopts an open-source license to enable independent review and community contributions.

S3curePss was released in 2019 by the developer collective S3cureTech, with major updates in 2021 and 2023 that added multi-language bindings, improved performance, and enhanced HSM support. It has seen adoption in open-source packaging ecosystems and some enterprise PKI deployments, where RSASSA-PSS is used for software signing and package verification.

See also RSASSA-PSS, PKCS #1, digital signatures, and PKI.