CECPQ1 was designed to test algorithms that can provide confidentiality even against an attacker who possesses a large quantum computer. It is a key-agreement algorithm for TLS that combines X25519 and NewHope, a ring learning with errors primitive. Even if NewHope were to turn out to be compromised, the parallel X25519 key-agreement ensures that CECPQ1 provides at least the security of existing connections.[2]
It was available in Google Chrome 54 beta.[3] In 2016, its experimental use in Chrome ended and it was planned to be disabled in a later Chrome update.[4]
It was succeeded by CECPQ2.