text: // from https://github.com/Rantanen/node-dtls/blob/25a7dc861bda38cfeac93a723500eea4f0ac2e86/Certificate.js
  // thanks to @Rantanen
  
  'use strict'
  
  var asn = require('../asn1')
  
  var Time = asn.define('Time', function () {
    this.choice({
      utcTime: this.utctime(),
      generalTime: this.gentime()
    })
  })
  
  var AttributeTypeValue = asn.define('AttributeTypeValue', function () {
    this.seq().obj(
      this.key('type').objid(),
      this.key('value').any()
    )
  })
  
  var AlgorithmIdentifier = asn.define('AlgorithmIdentifier', function () {
    this.seq().obj(
      this.key('algorithm').objid(),
      this.key('parameters').optional(),
      this.key('curve').objid().optional()
    )
  })
  
  var SubjectPublicKeyInfo = asn.define('SubjectPublicKeyInfo', function () {
    this.seq().obj(
      this.key('algorithm').use(AlgorithmIdentifier),
      this.key('subjectPublicKey').bitstr()
    )
  })
  
  var RelativeDistinguishedName = asn.define('RelativeDistinguishedName', function () {
    this.setof(AttributeTypeValue)
  })
  
  var RDNSequence = asn.define('RDNSequence', function () {
    this.seqof(RelativeDistinguishedName)
  })
  
  var Name = asn.define('Name', function () {
    this.choice({
      rdnSequence: this.use(RDNSequence)
    })
  })
  
  var Validity = asn.define('Validity', function () {
    this.seq().obj(
      this.key('notBefore').use(Time),
      this.key('notAfter').use(Time)
    )
  })
  
  var Extension = asn.define('Extension', function () {
    this.seq().obj(
      this.key('extnID').objid(),
      this.key('critical').bool().def(false),
      this.key('extnValue').octstr()
    )
  })
  
  var TBSCertificate = asn.define('TBSCertificate', function () {
    this.seq().obj(
      this.key('version').explicit(0).int().optional(),
      this.key('serialNumber').int(),
      this.key('signature').use(AlgorithmIdentifier),
      this.key('issuer').use(Name),
      this.key('validity').use(Validity),
      this.key('subject').use(Name),
      this.key('subjectPublicKeyInfo').use(SubjectPublicKeyInfo),
      this.key('issuerUniqueID').implicit(1).bitstr().optional(),
      this.key('subjectUniqueID').implicit(2).bitstr().optional(),
      this.key('extensions').explicit(3).seqof(Extension).optional()
    )
  })
  
  var X509Certificate = asn.define('X509Certificate', function () {
    this.seq().obj(
      this.key('tbsCertificate').use(TBSCertificate),
      this.key('signatureAlgorithm').use(AlgorithmIdentifier),
      this.key('signatureValue').bitstr()
    )
  })
  
  module.exports = X509Certificate
  