org.eclipse.californium.elements.util

Class Asn1DerDecoder

java.lang.Object

org.eclipse.californium.elements.util.Asn1DerDecoder

public class Asn1DerDecoder
extends Object

ASN.1 DER decoder for SEQUENCEs and OIDs.

Constructor Summary

Constructors

Constructor and Description
Asn1DerDecoder()

Method Summary

Methods

Modifier and Type	Method and Description
static boolean	equalKeyAlgorithmSynonyms(String keyAlgorithm1, String keyAlgorithm2) Check for equal key algorithm synonyms.
static byte[]	readOidValue(DatagramReader reader) Read value of ASN.1 OID into byte array.
static byte[]	readSequenceEntity(DatagramReader reader) Read entity of ASN.1 SEQUENCE into byte array.
static byte[]	readSequenceValue(DatagramReader reader) Read value of ASN.1 SEQUENCE into byte array.
static String	readSubjectPublicKeyAlgorithm(byte[] data) Read key algorithm from subjects public key.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Asn1DerDecoder

public Asn1DerDecoder()

Method Detail

readSequenceEntity

public static byte[] readSequenceEntity(DatagramReader reader)

Read entity of ASN.1 SEQUENCE into byte array. Returns entity, including tag and length. Intended to be passed to other security readers as KeyFacotry or X509CertPath.

Parameters:

reader - reader containing the bytes to read.

Returns:

byte array containing the SEQUENCE entity.

Throws:

IllegalArgumentException - if provided bytes doesn't contain a SEQUENCE.

readSequenceValue

public static byte[] readSequenceValue(DatagramReader reader)

Read value of ASN.1 SEQUENCE into byte array. Returns only the value, excluding tag and length.

Parameters:

reader - reader containing the bytes to read.

Returns:

byte array containing the SEQUENCE value.

Throws:

IllegalArgumentException - if provided bytes doesn't contain a SEQUENCE.

readOidValue

public static byte[] readOidValue(DatagramReader reader)

Read value of ASN.1 OID into byte array. Read only value, excluding tag and length.

Parameters:

reader - reader containing the bytes to read.

Returns:

byte array containing the OID value.

Throws:

IllegalArgumentException - if provided bytes doesn't contain a OID.

readSubjectPublicKeyAlgorithm

public static String readSubjectPublicKeyAlgorithm(byte[] data)

Read key algorithm from subjects public key. Read key algorithm from subjects public key encoded in ASN.1 DER.

 SubjectPublicKeyInfo ::= SEQUENCE { 
    algorithm AlgorithmIdentifier,
    subjectPublicKey BIT STRING 
 } 
 
 AlgorithmIdentifier ::= SEQUENCE {
    algorithm OBJECT IDENTIFIER, 
    parameters ANY DEFINED BY algorithm OPTIONAL
 }
 

Figure 2: SubjectPublicKeyInfo ASN.1 Structure

Parameters:

data - byte array containing the subject public key.

Returns:

key algorithm name to be used by KeyFactory. Maybe null, if the OID of the subject public key is unknown.

Throws:

IllegalArgumentException - if provided bytes doesn't contain a subject public key.

equalKeyAlgorithmSynonyms

public static boolean equalKeyAlgorithmSynonyms(String keyAlgorithm1,
                                String keyAlgorithm2)

Check for equal key algorithm synonyms. Currently on "DH" and "DiffieHellman" are supported synonyms.

Parameters:

keyAlgorithm1 - key algorithm 1

keyAlgorithm2 - key algorithm 2

Returns:

true, if the key algorithms are equal or synonyms, false, otherwise.