_ Git - BoarSSL/blob - XKeys/AlgorithmIdentifier.cs

   1 /*
   2  * Copyright (c) 2017 Thomas Pornin <pornin@bolet.org>
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining
   5  * a copy of this software and associated documentation files (the
   6  * "Software"), to deal in the Software without restriction, including
   7  * without limitation the rights to use, copy, modify, merge, publish,
   8  * distribute, sublicense, and/or sell copies of the Software, and to
   9  * permit persons to whom the Software is furnished to do so, subject to
  10  * the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be
  13  * included in all copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  19  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  20  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  22  * SOFTWARE.
  23  */
  24
  25 using System;
  26
  27 using Asn1;
  28
  29 /*
  30  * A wrapper class for an AlgorithmIdentifier (SEQUENCE of an OID
  31  * then optional parameters).
  32  */
  33
  34 class AlgorithmIdentifier {
  35
  36         /*
  37          * Get the OID that identifies the algorithm.
  38          */
  39         internal string OID {
  40                 get {
  41                         return oid;
  42                 }
  43         }
  44
  45         /*
  46          * Get the algorithm parameters. This may be null if the
  47          * structure did not contain parameters.
  48          */
  49         internal AsnElt Parameters {
  50                 get {
  51                         return parameters;
  52                 }
  53         }
  54
  55         string oid;
  56         AsnElt parameters;
  57
  58         /*
  59          * Create an instance over the provided ASN.1 element. The
  60          * outer tag will be checked to match the universal tag for
  61          * SEQUENCE.
  62          */
  63         internal AlgorithmIdentifier(AsnElt ai) : this(ai, true)
  64         {
  65         }
  66
  67         /*
  68          * Create an instance over the provided ASN.1 element. If
  69          * 'checkTag' is true, then the outer tag will be checked to
  70          * match the universal tag for SEQUENCE. Set 'checkTag' to
  71          * false if the tag was already checked, or if it has been
  72          * overwritten with an implicit tag.
  73          */
  74         internal AlgorithmIdentifier(AsnElt ai, bool checkTag)
  75         {
  76                 if (checkTag) {
  77                         ai.CheckTag(AsnElt.SEQUENCE);
  78                 }
  79                 ai.CheckNumSubMin(1);
  80                 ai.CheckNumSubMax(2);
  81                 AsnElt ao = ai.GetSub(0);
  82                 ao.CheckTag(AsnElt.OBJECT_IDENTIFIER);
  83                 oid = ao.GetOID();
  84                 if (ai.Sub.Length >= 2) {
  85                         parameters = ai.GetSub(1);
  86                 } else {
  87                         parameters = null;
  88                 }
  89         }
  90
  91         /*
  92          * Create a new instance for a given OID, with no parameters.
  93          */
  94         internal AlgorithmIdentifier(string oid) : this(oid, null)
  95         {
  96         }
  97
  98         /*
  99          * Create a new instance for a given OID, with the provided
 100          * parameters (which may be null).
 101          */
 102         internal AlgorithmIdentifier(string oid, AsnElt parameters)
 103         {
 104                 this.oid = oid;
 105                 this.parameters = parameters;
 106         }
 107
 108         /*
 109          * Encode this instance as a new ASN.1 object.
 110          */
 111         internal AsnElt ToAsn1()
 112         {
 113                 AsnElt ao = AsnElt.MakeOID(oid);
 114                 if (parameters == null) {
 115                         return AsnElt.Make(AsnElt.SEQUENCE, ao);
 116                 } else {
 117                         return AsnElt.Make(AsnElt.SEQUENCE, ao, parameters);
 118                 }
 119         }
 120 }