铜锁/Tongsuo is a Modern Cryptographic Primitives and Protocols Library

Windows Secure Shell Client With Support For Smart Cards, Certificates, & FIDO Keys

TinyPKI is a lightweight C11/OpenSSL PKI core for constrained IoT and edge networks, combining ECQV implicit certificates, sparse Merkle revocation proofs, MMR issuance transparency, CA-signed checkpoints, t-of-n edge witnesses, and SM2/SM3/SM4 sessions.

P2P DNS with content key, crypto key and PKI support. DynDNS alternative.

Heimdal

Easy-to-use high-level library for PKI-enabled applications

An OpenSSL-based implementation of the Certificate Management Protocol (CMP), defined in IETF RFCs 4210, 4211, and 6712. It is being extended according to the emerging RFCs 'CMP Updates' (CMPv3), 'CMP Algorithms', and 'Lightweight CMP Profile'.

WebCert is a Web application to generate and manage digital certificates in cases where no "full" CA is needed.

Microchip AVR based smartcard/token with ECC and RSA cryptography

A set of example programs that demonstrate various OpenSSL functions and enable "learning by doing".

openssl_ca with QT GUI

gnoMint: Certification Authority management made easy

a purly Peer-to-Peer instant messenger client

An ongoing & curated collection of awesome software best practices and techniques, libraries and frameworks, E-books and videos, websites, blog posts, links to github Repositories, technical guidelines and important resources about Public Key Infrastructure (PKI) in Cybersecurity.

A lightweight library that interfaces PKCS#11 libraries, with the added functionality of supporting CAdES-BES signing natively

这是一个PuTTY-CAC中文版，与PuTTY-CAC相同，是一个支持智能卡、证书和FIDO密钥的Windows Secure Shell客户端。更多详细信息，请访问PuTTY-CAC相关网站及说明。

Windows Certificate Store Aggregator

Simple ACME client written in C

X.509 PKI from scratch — CA, CSR, certificates, ASN.1/DER, SHA-512, RSA in C