1 use der::{
2     asn1::{AnyRef, ObjectIdentifier},
3     DecodeValue, EncodeValue, FixedTag, Header, Length, Reader, Tag, Writer,
4 };
5 
6 /// Elliptic curve parameters as described in
7 /// [RFC5480 Section 2.1.1](https://datatracker.ietf.org/doc/html/rfc5480#section-2.1.1):
8 ///
9 /// ```text
10 /// ECParameters ::= CHOICE {
11 ///   namedCurve         OBJECT IDENTIFIER
12 ///   -- implicitCurve   NULL
13 ///   -- specifiedCurve  SpecifiedECDomain
14 /// }
15 ///   -- implicitCurve and specifiedCurve MUST NOT be used in PKIX.
16 ///   -- Details for SpecifiedECDomain can be found in [X9.62].
17 ///   -- Any future additions to this CHOICE should be coordinated
18 ///   -- with ANSI X9.
19 /// ```
20 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
21 pub enum EcParameters {
22     /// Elliptic curve named by a particular OID.
23     ///
24     /// > namedCurve identifies all the required values for a particular
25     /// > set of elliptic curve domain parameters to be represented by an
26     /// > object identifier.
27     NamedCurve(ObjectIdentifier),
28 }
29 
30 impl<'a> DecodeValue<'a> for EcParameters {
decode_value<R: Reader<'a>>(decoder: &mut R, header: Header) -> der::Result<Self>31     fn decode_value<R: Reader<'a>>(decoder: &mut R, header: Header) -> der::Result<Self> {
32         ObjectIdentifier::decode_value(decoder, header).map(Self::NamedCurve)
33     }
34 }
35 
36 impl EncodeValue for EcParameters {
value_len(&self) -> der::Result<Length>37     fn value_len(&self) -> der::Result<Length> {
38         match self {
39             Self::NamedCurve(oid) => oid.value_len(),
40         }
41     }
42 
encode_value(&self, writer: &mut impl Writer) -> der::Result<()>43     fn encode_value(&self, writer: &mut impl Writer) -> der::Result<()> {
44         match self {
45             Self::NamedCurve(oid) => oid.encode_value(writer),
46         }
47     }
48 }
49 
50 impl EcParameters {
51     /// Obtain the `namedCurve` OID.
named_curve(self) -> Option<ObjectIdentifier>52     pub fn named_curve(self) -> Option<ObjectIdentifier> {
53         match self {
54             Self::NamedCurve(oid) => Some(oid),
55         }
56     }
57 }
58 
59 impl<'a> From<&'a EcParameters> for AnyRef<'a> {
from(params: &'a EcParameters) -> AnyRef<'a>60     fn from(params: &'a EcParameters) -> AnyRef<'a> {
61         match params {
62             EcParameters::NamedCurve(oid) => oid.into(),
63         }
64     }
65 }
66 
67 impl From<ObjectIdentifier> for EcParameters {
from(oid: ObjectIdentifier) -> EcParameters68     fn from(oid: ObjectIdentifier) -> EcParameters {
69         EcParameters::NamedCurve(oid)
70     }
71 }
72 
73 impl FixedTag for EcParameters {
74     const TAG: Tag = Tag::ObjectIdentifier;
75 }
76