Transport Layer Security (TLS) 2004-05-03 2018-08-10 Transport Layer Security (TLS) Yoav Nir, Rich Salz, Nick Sullivan 0-63 Standards Action 64-223 Specification Required 224-255 Reserved for Private Use Value 0 (NULL) is the only value in this registry applicable to (D)TLS protocol version 1.3 or later. 0 NULL 1 DEFLATE 2-63 Unassigned 64 LZS 65-223 Unassigned 224-255 Reserved for Private Use