OpenSSL 4.0 Introduces Post-Quantum Cryptography

OpenSSL 4.0 is released with support for post-quantum cryptographic algorithms, marking a significant step forward in securing communications against future quantum threats.

May 10, 2026 • 7 min read • kiotocloud Team
opensslsecuritycryptographyquantum

The OpenSSL project has released version 4.0, a landmark update that introduces support for post-quantum cryptography (PQC) algorithms.

Post-Quantum Support

OpenSSL 4.0 includes support for CRYSTALS-Kyber and CRYSTALS-Dilithium, the NIST-standardized post-quantum algorithms.

Other Improvements

  • TLS 1.4 support with enhanced security properties
  • Deprecated legacy algorithms including SHA-1 and 3DES
  • Improved FIPS 140-3 compliance module
  • New API for easier integration

Migration

Administrators should plan their migration to OpenSSL 4.0 carefully, as it removes several deprecated features and introduces new API patterns.