Class AlgorithmIdentifier

java.lang.Object
org.bouncycastle.asn1.ASN1Object
org.bouncycastle.asn1.x509.AlgorithmIdentifier
All Implemented Interfaces:
ASN1Encodable, Encodable
public class AlgorithmIdentifier extends ASN1Object

  • Constructor Details

  • Method Details

    • getInstance

      public static AlgorithmIdentifier getInstance(Object obj)

    • getInstance

      public static AlgorithmIdentifier getInstance(ASN1TaggedObject taggedObject, boolean declaredExplicit)

    • getTagged

      public static AlgorithmIdentifier getTagged(ASN1TaggedObject taggedObject, boolean declaredExplicit)

    • getAlgorithm

      public ASN1ObjectIdentifier getAlgorithm()

    • getParameters

      public ASN1Encodable getParameters()

    • areEquivalent

      public static boolean areEquivalent(AlgorithmIdentifier a, AlgorithmIdentifier b)
      Return true if two algorithm identifiers name the same algorithm carrying the same parameters, counting an absent parameters field and an explicit NULL as the same thing - both say "this algorithm takes no parameters", they simply say it differently.

      The two encodings are both in wide use for the SHA-2 digests, and RFC 5754 sec. 2 requires a receiver to take either: "Implementations MUST accept SHA2 AlgorithmIdentifiers with absent parameters. Implementations MUST accept SHA2 AlgorithmIdentifiers with NULL parameters." - while requiring that they be generated with the parameters absent. ASN1Object.equals(Object) compares the encodings and so separates them, which is right for a map key but wrong for deciding whether a peer named the algorithm we expected.

      Note this only equates absent with NULL; an identifier carrying an actual parameter structure is never equivalent to one carrying none.

      Parameters:
      a - an algorithm identifier, may be null.
      b - an algorithm identifier, may be null.
      Returns:
      true if the two name the same algorithm with the same parameters.

    • toASN1Primitive

      public ASN1Primitive toASN1Primitive()
      Produce an object suitable for an ASN1OutputStream. 
           AlgorithmIdentifier ::= SEQUENCE {
                           algorithm OBJECT IDENTIFIER,
                           parameters ANY DEFINED BY algorithm OPTIONAL }
      Specified by:
      toASN1Primitive in interface ASN1Encodable
      Specified by:
      toASN1Primitive in class ASN1Object
      Returns:
      a primitive representation of this object.