http://ftpfaudev4triw2vxiwzf4334e3mynz7osqgtozhbc77fixncqzbyoyd.onion/ripe.net/rfc/rfc8994.html
The choice for TLS 1.2 as the lowest common denominator for the ACP is based on the currently expected and most likely availability across the wide range of candidate ACP node types, potentially with non-agile operating system TCP/IP stacks. ¶ TLS MUST offer TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 and TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 and MUST NOT offer options with less than 256-bit symmetric key strength or hash strength of less than 384 bits.