Class: TTTLS13::SharedSecret

Inherits:
Object
  • Object
show all
Defined in:
lib/tttls1.3/shared_secret.rb

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ SharedSecret

Returns a new instance of SharedSecret.



6
7
8
 
# File 'lib/tttls1.3/shared_secret.rb', line 6

def initialize
  @priv_keys = {}
end

Class Method Details

.gen_from_named_groups(groups) ⇒ TTTLS13::SharedSecret

Parameters:

Returns:



97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
 
# File 'lib/tttls1.3/shared_secret.rb', line 97

def self.gen_from_named_groups(groups)
  shared_secret = SharedSecret.new

  groups.each do |group|
    case group
    when NamedGroup::SECP256R1, NamedGroup::SECP384R1, NamedGroup::SECP521R1
      curve = NamedGroup.curve_name(group)
      ec = OpenSSL::PKey::EC.generate(curve)
      shared_secret.store!(group, ec)
    when NamedGroup::X25519, NamedGroup::X448
      pkey = OpenSSL::PKey.generate_key(NamedGroup.curve_name(group))
      shared_secret.store!(group, pkey)
    else
      # not supported other NamedGroup
      raise Error::ErrorAlerts, :internal_error
    end
  end

  shared_secret
end

Instance Method Details

#[](group) ⇒ OpenSSL::PKey::EC.$Object | OpenSSL::PKey::PKey.$Object

Returns ].

Parameters:

  • group (TTTLS13::Message::Extension::NamedGroup)

Returns:

  • (OpenSSL::PKey::EC.$Object | OpenSSL::PKey::PKey.$Object) —

    ]



90
91
92
 
# File 'lib/tttls1.3/shared_secret.rb', line 90

def [](group)
  @priv_keys[group]
end

#build(group, key_exchange) ⇒ Object

rubocop: disable Metrics/MethodLength

Parameters:

Returns:

  • String



21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
 
# File 'lib/tttls1.3/shared_secret.rb', line 21

def build(group, key_exchange)
  case group
  when NamedGroup::SECP256R1, NamedGroup::SECP384R1, NamedGroup::SECP521R1
    curve = NamedGroup.curve_name(group)
    pub_key = OpenSSL::PKey::EC::Point.new(
      OpenSSL::PKey::EC::Group.new(curve),
      OpenSSL::BN.new(key_exchange, 2)
    )
    @priv_keys[group].dh_compute_key(pub_key)
  when NamedGroup::X25519
    asn1_seq = OpenSSL::ASN1.Sequence(
      [
        OpenSSL::ASN1.Sequence(
          [
            # https://datatracker.ietf.org/doc/html/rfc8410#section-3
            OpenSSL::ASN1.ObjectId('1.3.101.110')
          ]
        ),
        OpenSSL::ASN1.BitString(key_exchange)
      ]
    )

    @priv_keys[group].derive(OpenSSL::PKey.read(asn1_seq.to_der))
  when NamedGroup::X448
    asn1_seq = OpenSSL::ASN1.Sequence(
      [
        OpenSSL::ASN1.Sequence(
          [
            # https://datatracker.ietf.org/doc/html/rfc8410#section-3
            OpenSSL::ASN1.ObjectId('1.3.101.111')
          ]
        ),
        OpenSSL::ASN1.BitString(key_exchange)
      ]
    )

    @priv_keys[group].derive(OpenSSL::PKey.read(asn1_seq.to_der))
  else
    # not supported other NamedGroup
    raise Error::ErrorAlerts, :internal_error
  end
end

#key_share_entries ⇒ Array of TTTLS13::Message::Extensions::KeyShare

Returns:

  • (Array of TTTLS13::Message::Extensions::KeyShare) 


66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
 
# File 'lib/tttls1.3/shared_secret.rb', line 66

def key_share_entries
  @priv_keys.map do |group, priv_key|
    case group
    when NamedGroup::SECP256R1, NamedGroup::SECP384R1, NamedGroup::SECP521R1
      Message::Extension::KeyShareEntry.new(
        group:,
        key_exchange: priv_key.public_key.to_octet_string(:uncompressed)
      )
    when NamedGroup::X25519, NamedGroup::X448
      n_pk = NamedGroup.key_exchange_len(group)
      Message::Extension::KeyShareEntry.new(
        group:,
        key_exchange: priv_key.public_to_der[-n_pk, n_pk]
      )
    else
      # not supported other NamedGroup
      raise Error::ErrorAlerts, :internal_error
    end
  end
end

#store!(group, priv_key) ⇒ Object

Parameters:

  • group (TTTLS13::NamedGroup)
  • priv_key (OpenSSL::PKey::EC.$Object | OpenSSL::PKey::PKey.$Object) 


12
13
14
 
# File 'lib/tttls1.3/shared_secret.rb', line 12

def store!(group, priv_key)
  @priv_keys[group] = priv_key
end