protocol_ext_supportedgroups.py

# ------------------------------------------------------------------------------
# Supported Groups Extension
#   - RFC 8446 #appendix-B.3.1.4
#     * https://datatracker.ietf.org/doc/html/rfc8446#appendix-B.3.1.4
# ------------------------------------------------------------------------------

from metatype import Uint16, List, Enum
import metastruct as meta

### NamedGroup ###
# enum {
#     /* Elliptic Curve Groups (ECDHE) */
#     obsolete_RESERVED(0x0001..0x0016),
#     secp256r1(0x0017), secp384r1(0x0018), secp521r1(0x0019),
#     obsolete_RESERVED(0x001A..0x001C),
#     x25519(0x001D), x448(0x001E),
#     ...
#     (0xFFFF)
# } NamedGroup;
#
# 鍵交換のための群
class NamedGroup(Enum):
    elem_t = Uint16  # (0xFFFF)

    # Elliptic Curve Groups (ECDHE)
    #obsolete_RESERVED = Uint16(0x0001)..Uint16(0x0016)
    secp256r1 = Uint16(0x0017)
    secp384r1 = Uint16(0x0018)
    secp521r1 = Uint16(0x0019)
    #obsolete_RESERVED = Uint16(0x001A)..Uint16(0x001C)
    x25519 = Uint16(0x001D)
    x448 = Uint16(0x001E)

    # Finite Field Groups (DHE)
    # https://tools.ietf.org/html/rfc7919#appendix-A
    ffdhe2048 = Uint16(0x0100)
    ffdhe3072 = Uint16(0x0101)
    ffdhe4096 = Uint16(0x0102)
    ffdhe6144 = Uint16(0x0103)
    ffdhe8192 = Uint16(0x0104)

    # Reserved Code Points
    #ffdhe_private_use = Uint16(0x01FC)..Uint16(0x01FF)
    #ecdhe_private_use = Uint16(0xFE00)..Uint16(0xFEFF)
    #obsolete_RESERVED = Uint16(0xFF01)..Uint16(0xFF02)

NamedGroups = List(size_t=Uint16, elem_t=NamedGroup)

### NamedGroupList ###
# struct {
#     NamedGroup named_group_list<2..2^16-1>;
# } NamedGroupList;
#
@meta.struct
class NamedGroupList(meta.MetaStruct):
    named_group_list: NamedGroups