target = "https://tools.ietf.org/rfc/rfc8446#5"

# 5.  Record Protocol
#
# The TLS record protocol takes messages to be transmitted, fragments
# the data into manageable blocks, protects the records, and transmits
# the result.  Received data is verified, decrypted, reassembled, and
# then delivered to higher-level clients.
# 
# TLS records are typed, which allows multiple higher-level protocols
# to be multiplexed over the same record layer.  This document
# specifies four content types: handshake, application_data, alert, and
# change_cipher_spec.  The change_cipher_spec record is used only for
# compatibility purposes (see Appendix D.4).
# 
# An implementation may receive an unencrypted record of type
# change_cipher_spec consisting of the single byte value 0x01 at any
# time after the first ClientHello message has been sent or received
# and before the peer's Finished message has been received and MUST
# simply drop it without further processing.  Note that this record may
# appear at a point at the handshake where the implementation is
# expecting protected records, and so it is necessary to detect this
# condition prior to attempting to deprotect the record.  An
# implementation which receives any other change_cipher_spec value or
# which receives a protected change_cipher_spec record MUST abort the
# handshake with an "unexpected_message" alert.  If an implementation
# detects a change_cipher_spec record received before the first
# ClientHello message or after the peer's Finished message, it MUST be
# treated as an unexpected record type (though stateless servers may
# not be able to distinguish these cases from allowed cases).
# 
# Implementations MUST NOT send record types not defined in this
# document unless negotiated by some extension.  If a TLS
# implementation receives an unexpected record type, it MUST terminate
# the connection with an "unexpected_message" alert.  New record
# content type values are assigned by IANA in the TLS ContentType
# registry as described in Section 11.

[[spec]]
level = "MUST"
quote = '''
An implementation may receive an unencrypted record of type
change_cipher_spec consisting of the single byte value 0x01 at any
time after the first ClientHello message has been sent or received
and before the peer's Finished message has been received and MUST
simply drop it without further processing.
'''

[[spec]]
level = "MUST"
quote = '''
An
implementation which receives any other change_cipher_spec value or
which receives a protected change_cipher_spec record MUST abort the
handshake with an "unexpected_message" alert.
'''

[[spec]]
level = "MUST"
quote = '''
If an implementation
detects a change_cipher_spec record received before the first
ClientHello message or after the peer's Finished message, it MUST be
treated as an unexpected record type (though stateless servers may
not be able to distinguish these cases from allowed cases).
'''

[[spec]]
level = "MUST"
quote = '''
Implementations MUST NOT send record types not defined in this
document unless negotiated by some extension.
'''

[[spec]]
level = "MUST"
quote = '''
If a TLS
implementation receives an unexpected record type, it MUST terminate
the connection with an "unexpected_message" alert.
'''