com.cms.crypto
Class HMACWithSHA1

java.lang.Object
  schemajic.model.ASN1Value
      schemajic.model.ASN1Sequence
          com.cms.types.MessageAuthenticationCodeAlgorithm
              com.cms.crypto.HMACWithSHA1

public class HMACWithSHA1
extends MessageAuthenticationCodeAlgorithm

An algorithm identifier for the Hashed MAC with SHA1 (HMAC) algorithm.

For this hashed MAC algorithm, the open type must contain the complete encoding of a value of type NULL. The value of an open type is not visible to the codec, which conforms to the requirements for open types in the ASN.1 standards. So, the value of the parameters component of an AlgorithmIdentifier type must be pre- encoded and set before the value of AlgorithmIdentifier type can be encoded.

 From IETF RFC 3370 

 The HMAC with SHA-1 algorithm is described in RFC 2104 [HMAC].  The
 algorithm identifier for HMAC with SHA-1 is:

    hMAC-SHA1 OBJECT IDENTIFIER ::= { iso(1)
       identified-organization(3) dod(6) internet(1) security(5)
       mechanisms(5) 8 1 2 }
 

There are two possible encodings for the HMAC with SHA-1 AlgorithmIdentifier parameters field. The two alternatives arise from the fact that when the 1988 syntax for the AlgorithmIdentifier type was translated into the 1997 syntax, the OPTIONAL associated with the AlgorithmIdentifier parameters got lost. Later the OPTIONAL was recovered via a defect report, but by then many people thought that algorithm parameters were mandatory. Because of this history some implementations may encode parameters as a NULL while others omit them entirely.

The AlgorithmIdentifier parameters field is OPTIONAL. If present, the parameters field MUST contain a NULL. Implementations MUST treat HMAC with SHA-1 AlgorithmIdentifiers with absent parameters as valid. Implementations MUST treat HMAC with SHA-1 AlgorithmIdentifiers with NULL parameters as valid. Implementations SHOULD generate HMAC with SHA-1 AlgorithmIdentifiers with absent parameters.

Version:

1.00 - 2006/01/17

Author:

support@phillipgriffin.com

Field Summary

Fields inherited from class schemajic.model.ASN1Sequence

_fields

Constructor Summary

HMACWithSHA1()
Constructor for HMACWithSHA1 with no parameters.

HMACWithSHA1(ASN1OpenType parameters)
Constructor for HMACWithSHA1 with parameters expressed as a valid encoding of a value of ASN.1 type NULL.

Method Summary

Methods inherited from class com.cms.types.MessageAuthenticationCodeAlgorithm

getAlgorithm, getAsn1Type, getDefaultValue, getParameters, setAlgorithm, setParameters

Methods inherited from class schemajic.model.ASN1Sequence

accept, getFields, setAbsent, setFields, setPresent

Methods inherited from class java.lang.Object

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

Constructor Detail

HMACWithSHA1

public HMACWithSHA1()

Constructor for HMACWithSHA1 with no parameters.

HMACWithSHA1

public HMACWithSHA1(ASN1OpenType parameters)

Constructor for HMACWithSHA1 with parameters expressed as a valid encoding of a value of ASN.1 type NULL.

Parameters:

parameters - a valid ASN.1 encoded value