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<!DOCTYPE html>
<html lang="en" class="RFC">
<head>
<meta charset="utf-8">
<meta content="Common,Latin" name="scripts">
<meta content="initial-scale=1.0" name="viewport">
<title>RFC 8769: Cryptographic Message Syntax (CMS) Content Types for Concise Binary Object Representation (CBOR)</title>
<meta content="Jim Schaad" name="author">
<meta content="
       
        Concise Binary Object Representation (CBOR) is becoming a widely used method of doing content encoding.
        The Cryptographic Message Syntax (CMS) is still a widely used method of doing message-based security.
        This document defines a set of content types for CMS that hold CBOR content.
       
    " name="description">
<meta content="xml2rfc 2.41.0" name="generator">
<meta content="8769" name="rfc.number">
<link href="rfc8769.xml" rel="alternate" type="application/rfc+xml">
<link href="#copyright" rel="license">
<style type="text/css">/*

  NOTE: Changes at the bottom of this file overrides some earlier settings.

  Once the style has stabilized and has been adopted as an official RFC style,
  this can be consolidated so that style settings occur only in one place, but
  for now the contents of this file consists first of the initial CSS work as
  provided to the RFC Formatter (xml2rfc) work, followed by itemized and
  commented changes found necssary during the development of the v3
  formatters.

*/

/* fonts */
@import url('https://fonts.googleapis.com/css?family=Noto+Sans'); /* Sans-serif */
@import url('https://fonts.googleapis.com/css?family=Noto+Serif'); /* Serif (print) */
@import url('https://fonts.googleapis.com/css?family=Roboto+Mono'); /* Monospace */

@viewport {
  zoom: 1.0;
  width: extend-to-zoom;
}
@-ms-viewport {
  width: extend-to-zoom;
  zoom: 1.0;
}
/* general and mobile first */
html {
}
body {
  max-width: 90%;
  margin: 1.5em auto;
  color: #222;
  background-color: #fff;
  font-size: 14px;
  font-family: 'Noto Sans', Arial, Helvetica, sans-serif;
  line-height: 1.6;
  scroll-behavior: smooth;
}
.ears {
  display: none;
}

/* headings */
#title, h1, h2, h3, h4, h5, h6 {
  margin: 1em 0 0.5em;
  font-weight: bold;
  line-height: 1.3;
}
#title {
  clear: both;
  border-bottom: 1px solid #ddd;
  margin: 0 0 0.5em 0;
  padding: 1em 0 0.5em;
}
.author {
  padding-bottom: 4px;
}
h1 {
  font-size: 26px;
  margin: 1em 0;
}
h2 {
  font-size: 22px;
  margin-top: -20px;  /* provide offset for in-page anchors */
  padding-top: 33px;
}
h3 {
  font-size: 18px;
  margin-top: -36px;  /* provide offset for in-page anchors */
  padding-top: 42px;
}
h4 {
  font-size: 16px;
  margin-top: -36px;  /* provide offset for in-page anchors */
  padding-top: 42px;
}
h5, h6 {
  font-size: 14px;
}
#n-copyright-notice {
  border-bottom: 1px solid #ddd;
  padding-bottom: 1em;
  margin-bottom: 1em;
}
/* general structure */
p {
  padding: 0;
  margin: 0 0 1em 0;
  text-align: left;
}
div, span {
  position: relative;
}
div {
  margin: 0;
}
.alignRight.art-text {
  background-color: #f9f9f9;
  border: 1px solid #eee;
  border-radius: 3px;
  padding: 1em 1em 0;
  margin-bottom: 1.5em;
}
.alignRight.art-text pre {
  padding: 0;
}
.alignRight {
  margin: 1em 0;
}
.alignRight > *:first-child {
  border: none;
  margin: 0;
  float: right;
  clear: both;
}
.alignRight > *:nth-child(2) {
  clear: both;
  display: block;
  border: none;
}
svg {
  display: block;
}
.alignCenter.art-text {
  background-color: #f9f9f9;
  border: 1px solid #eee;
  border-radius: 3px;
  padding: 1em 1em 0;
  margin-bottom: 1.5em;
}
.alignCenter.art-text pre {
  padding: 0;
}
.alignCenter {
  margin: 1em 0;
}
.alignCenter > *:first-child {
  border: none;
  /* this isn't optimal, but it's an existence proof.  PrinceXML doesn't
     support flexbox yet.
  */
  display: table;
  margin: 0 auto;
}

/* lists */
ol, ul {
  padding: 0;
  margin: 0 0 1em 2em;
}
ol ol, ul ul, ol ul, ul ol {
  margin-left: 1em;
}
li {
  margin: 0 0 0.25em 0;
}
.ulCompact li {
  margin: 0;
}
ul.empty, .ulEmpty {
  list-style-type: none;
}
ul.empty li, .ulEmpty li {
  margin-top: 0.5em;
}
ul.compact, .ulCompact,
ol.compact, .olCompact {
  line-height: 100%;
  margin: 0 0 0 2em;
}

/* definition lists */
dl {
}
dl > dt {
  float: left;
  margin-right: 1em;
}
/* 
dl.nohang > dt {
  float: none;
}
*/
dl > dd {
  margin-bottom: .8em;
  min-height: 1.3em;
}
dl.compact > dd, .dlCompact > dd {
  margin-bottom: 0em;
}
dl > dd > dl {
  margin-top: 0.5em;
  margin-bottom: 0em;
}

/* links */
a {
  text-decoration: none;
}
a[href] {
  color: #22e; /* Arlen: WCAG 2019 */
}
a[href]:hover {
  background-color: #f2f2f2;
}
figcaption a[href],
a[href].selfRef {
  color: #222;
}
/* XXX probably not this:
a.selfRef:hover {
  background-color: transparent;
  cursor: default;
} */

/* Figures */
tt, code, pre, code {
  background-color: #f9f9f9;
  font-family: 'Roboto Mono', monospace;
}
pre {
  border: 1px solid #eee;
  margin: 0;
  padding: 1em;
}
img {
  max-width: 100%;
}
figure {
  margin: 0;
}
figure blockquote {
  margin: 0.8em 0.4em 0.4em;
}
figcaption {
  font-style: italic;
  margin: 0 0 1em 0;
}
@media screen {
  pre {
    overflow-x: auto;
    max-width: 100%;
    max-width: calc(100% - 22px);
  }
}

/* aside, blockquote */
aside, blockquote {
  margin-left: 0;
  padding: 1.2em 2em;
}
blockquote {
  background-color: #f9f9f9;
  color: #111; /* Arlen: WCAG 2019 */
  border: 1px solid #ddd;
  border-radius: 3px;
  margin: 1em 0;
}
cite {
  display: block;
  text-align: right;
  font-style: italic;
}

/* tables */
table {
  width: 100%;
  margin: 0 0 1em;
  border-collapse: collapse;
  border: 1px solid #eee;
}
th, td {
  text-align: left;
  vertical-align: top;
  padding: 0.5em 0.75em;
}
th {
  text-align: left;
  background-color: #e9e9e9;
}
tr:nth-child(2n+1) > td {
  background-color: #f5f5f5;
}
table caption {
  font-style: italic;
  margin: 0;
  padding: 0;
  text-align: left;
}
table p {
  /* XXX to avoid bottom margin on table row signifiers. If paragraphs should
     be allowed within tables more generally, it would be far better to select on a class. */
  margin: 0;
}

/* pilcrow */
a.pilcrow {
  color: #666; /* Arlen: AHDJ 2019 */
  text-decoration: none;
  visibility: hidden;
  user-select: none;
  -ms-user-select: none;
  -o-user-select:none;
  -moz-user-select: none;
  -khtml-user-select: none;
  -webkit-user-select: none;
  -webkit-touch-callout: none;
}
@media screen {
  aside:hover > a.pilcrow,
  p:hover > a.pilcrow,
  blockquote:hover > a.pilcrow,
  div:hover > a.pilcrow,
  li:hover > a.pilcrow,
  pre:hover > a.pilcrow {
    visibility: visible;
  }
  a.pilcrow:hover {
    background-color: transparent;
  }
}

/* misc */
hr {
  border: 0;
  border-top: 1px solid #eee;
}
.bcp14 {
  font-variant: small-caps;
}

.role {
  font-variant: all-small-caps;
}

/* info block */
#identifiers {
  margin: 0;
  font-size: 0.9em;
}
#identifiers dt {
  width: 3em;
  clear: left;
}
#identifiers dd {
  float: left;
  margin-bottom: 0;
}
#identifiers .authors .author {
  display: inline-block;
  margin-right: 1.5em;
}
#identifiers .authors .org {
  font-style: italic;
}

/* The prepared/rendered info at the very bottom of the page */
.docInfo {
  color: #666; /* Arlen: WCAG 2019 */
  font-size: 0.9em;
  font-style: italic;
  margin-top: 2em;
}
.docInfo .prepared {
  float: left;
}
.docInfo .prepared {
  float: right;
}

/* table of contents */
#toc  {
  padding: 0.75em 0 2em 0;
  margin-bottom: 1em;
}
nav.toc ul {
  margin: 0 0.5em 0 0;
  padding: 0;
  list-style: none;
}
nav.toc li {
  line-height: 1.3em;
  margin: 0.75em 0;
  padding-left: 1.2em;
  text-indent: -1.2em;
}
/* references */
.references dt {
  text-align: right;
  font-weight: bold;
  min-width: 7em;
}
.references dd {
  margin-left: 8em;
  overflow: auto;
}

.refInstance {
  margin-bottom: 1.25em;
}

.references .ascii {
  margin-bottom: 0.25em;
}

/* index */
.index ul {
  margin: 0 0 0 1em;
  padding: 0;
  list-style: none;
}
.index ul ul {
  margin: 0;
}
.index li {
  margin: 0;
  text-indent: -2em;
  padding-left: 2em;
  padding-bottom: 5px;
}
.indexIndex {
  margin: 0.5em 0 1em;
}
.index a {
  font-weight: 700;
}
/* make the index two-column on all but the smallest screens */
@media (min-width: 600px) {
  .index ul {
    -moz-column-count: 2;
    -moz-column-gap: 20px;
  }
  .index ul ul {
    -moz-column-count: 1;
    -moz-column-gap: 0;
  }
}

/* authors */
address.vcard {
  font-style: normal;
  margin: 1em 0;
}

address.vcard .nameRole {
  font-weight: 700;
  margin-left: 0;
}
address.vcard .label {
  font-family: "Noto Sans",Arial,Helvetica,sans-serif;
  margin: 0.5em 0;
}
address.vcard .type {
  display: none;
}
.alternative-contact {
  margin: 1.5em 0 1em;
}
hr.addr {
  border-top: 1px dashed;
  margin: 0;
  color: #ddd;
  max-width: calc(100% - 16px);
}

/* temporary notes */
.rfcEditorRemove::before {
  position: absolute;
  top: 0.2em;
  right: 0.2em;
  padding: 0.2em;
  content: "The RFC Editor will remove this note";
  color: #9e2a00; /* Arlen: WCAG 2019 */
  background-color: #ffd; /* Arlen: WCAG 2019 */
}
.rfcEditorRemove {
  position: relative;
  padding-top: 1.8em;
  background-color: #ffd; /* Arlen: WCAG 2019 */
  border-radius: 3px;
}
.cref {
  background-color: #ffd; /* Arlen: WCAG 2019 */
  padding: 2px 4px;
}
.crefSource {
  font-style: italic;
}
/* alternative layout for smaller screens */
@media screen and (max-width: 1023px) {
  body {
    padding-top: 2em;
  }
  #title {
    padding: 1em 0;
  }
  h1 {
    font-size: 24px;
  }
  h2 {
    font-size: 20px;
    margin-top: -18px;  /* provide offset for in-page anchors */
    padding-top: 38px;
  }
  #identifiers dd {
    max-width: 60%;
  }
  #toc {
    position: fixed;
    z-index: 2;
    top: 0;
    right: 0;
    padding: 0;
    margin: 0;
    background-color: inherit;
    border-bottom: 1px solid #ccc;
  }
  #toc h2 {
    margin: -1px 0 0 0;
    padding: 4px 0 4px 6px;
    padding-right: 1em;
    min-width: 190px;
    font-size: 1.1em;
    text-align: right;
    background-color: #444;
    color: white;
    cursor: pointer;
  }
  #toc h2::before { /* css hamburger */
    float: right;
    position: relative;
    width: 1em;
    height: 1px;
    left: -164px;
    margin: 6px 0 0 0;
    background: white none repeat scroll 0 0;
    box-shadow: 0 4px 0 0 white, 0 8px 0 0 white;
    content: "";
  }
  #toc nav {
    display: none;
    padding: 0.5em 1em 1em;
    overflow: auto;
    height: calc(100vh - 48px);
    border-left: 1px solid #ddd;
  }
}

/* alternative layout for wide screens */
@media screen and (min-width: 1024px) {
  body {
    max-width: 724px;
    margin: 42px auto;
    padding-left: 1.5em;
    padding-right: 29em;
  }
  #toc {
    position: fixed;
    top: 42px;
    right: 42px;
    width: 25%;
    margin: 0;
    padding: 0 1em;
    z-index: 1;
  }
  #toc h2 {
    border-top: none;
    border-bottom: 1px solid #ddd;
    font-size: 1em;
    font-weight: normal;
    margin: 0;
    padding: 0.25em 1em 1em 0;
  }
  #toc nav {
    display: block;
    height: calc(90vh - 84px);
    bottom: 0;
    padding: 0.5em 0 0;
    overflow: auto;
  }
  img { /* future proofing */
    max-width: 100%;
    height: auto;
  }
}

/* pagination */
@media print {
  body {

    width: 100%;
  }
  p {
    orphans: 3;
    widows: 3;
  }
  #n-copyright-notice {
    border-bottom: none;
  }
  #toc, #n-introduction {
    page-break-before: always;
  }
  #toc {
    border-top: none;
    padding-top: 0;
  }
  figure, pre {
    page-break-inside: avoid;
  }
  figure {
    overflow: scroll;
  }
  h1, h2, h3, h4, h5, h6 {
    page-break-after: avoid;
  }
  h2+*, h3+*, h4+*, h5+*, h6+* {
    page-break-before: avoid;
  }
  pre {
    white-space: pre-wrap;
    word-wrap: break-word;
    font-size: 10pt;
  }
  table {
    border: 1px solid #ddd;
  }
  td {
    border-top: 1px solid #ddd;
  }
}

/* This is commented out here, as the string-set: doesn't
   pass W3C validation currently */
/*
.ears thead .left {
  string-set: ears-top-left content();
}

.ears thead .center {
  string-set: ears-top-center content();
}

.ears thead .right {
  string-set: ears-top-right content();
}

.ears tfoot .left {
  string-set: ears-bottom-left content();
}

.ears tfoot .center {
  string-set: ears-bottom-center content();
}

.ears tfoot .right {
  string-set: ears-bottom-right content();
}
*/

@page :first {
  padding-top: 0;
  @top-left {
    content: normal;
    border: none;
  }
  @top-center {
    content: normal;
    border: none;
  }
  @top-right {
    content: normal;
    border: none;
  }
}

@page {
  size: A4;
  margin-bottom: 45mm;
  padding-top: 20px;
  /* The follwing is commented out here, but set appropriately by in code, as
     the content depends on the document */
  /*
  @top-left {
    content: 'Internet-Draft';
    vertical-align: bottom;
    border-bottom: solid 1px #ccc;
  }
  @top-left {
    content: string(ears-top-left);
    vertical-align: bottom;
    border-bottom: solid 1px #ccc;
  }
  @top-center {
    content: string(ears-top-center);
    vertical-align: bottom;
    border-bottom: solid 1px #ccc;
  }
  @top-right {
    content: string(ears-top-right);
    vertical-align: bottom;
    border-bottom: solid 1px #ccc;
  }
  @bottom-left {
    content: string(ears-bottom-left);
    vertical-align: top;
    border-top: solid 1px #ccc;
  }
  @bottom-center {
    content: string(ears-bottom-center);
    vertical-align: top;
    border-top: solid 1px #ccc;
  }
  @bottom-right {
      content: '[Page ' counter(page) ']';
      vertical-align: top;
      border-top: solid 1px #ccc;
  }
  */

}

/* Changes introduced to fix issues found during implementation */
/* Make sure links are clickable even if overlapped by following H* */
a {
  z-index: 2;
}
/* Separate body from document info even without intervening H1 */
section {
  clear: both;
}


/* Top align author divs, to avoid names without organization dropping level with org names */
.author {
  vertical-align: top;
}

/* Leave room in document info to show Internet-Draft on one line */
#identifiers dt {
  width: 8em;
}

/* Don't waste quite as much whitespace between label and value in doc info */
#identifiers dd {
  margin-left: 1em;
}

/* Give floating toc a background color (needed when it's a div inside section */
#toc {
  background-color: white;
}

/* Make the collapsed ToC header render white on gray also when it's a link */
@media screen and (max-width: 1023px) {
  #toc h2 a,
  #toc h2 a:link,
  #toc h2 a:focus,
  #toc h2 a:hover,
  #toc a.toplink,
  #toc a.toplink:hover {
    color: white;
    background-color: #444;
    text-decoration: none;
  }
}

/* Give the bottom of the ToC some whitespace */
@media screen and (min-width: 1024px) {
  #toc {
    padding: 0 0 1em 1em;
  }
}

/* Style section numbers with more space between number and title */
.section-number {
  padding-right: 0.5em;
}

/* prevent monospace from becoming overly large */
tt, code, pre, code {
  font-size: 95%;
}

/* Fix the height/width aspect for ascii art*/
pre.sourcecode,
.art-text pre {
  line-height: 1.12;
}


/* Add styling for a link in the ToC that points to the top of the document */
a.toplink {
  float: right;
  margin-right: 0.5em;
}

/* Fix the dl styling to match the RFC 7992 attributes */
dl > dt,
dl.dlParallel > dt {
  float: left;
  margin-right: 1em;
}
dl.dlNewline > dt {
  float: none;
}

/* Provide styling for table cell text alignment */
table td.text-left,
table th.text-left {
  text-align: left;
}
table td.text-center,
table th.text-center {
  text-align: center;
}
table td.text-right,
table th.text-right {
  text-align: right;
}

/* Make the alternative author contact informatio look less like just another
   author, and group it closer with the primary author contact information */
.alternative-contact {
  margin: 0.5em 0 0.25em 0;
}
address .non-ascii {
  margin: 0 0 0 2em;
}

/* With it being possible to set tables with alignment
  left, center, and right, { width: 100%; } does not make sense */
table {
  width: auto;
}

/* Avoid reference text that sits in a block with very wide left margin,
   because of a long floating dt label.*/
.references dd {
  overflow: visible;
}

/* Control caption placement */
caption {
  caption-side: bottom;
}

/* Limit the width of the author address vcard, so names in right-to-left
   script don't end up on the other side of the page. */

address.vcard {
  max-width: 30em;
  margin-right: auto;
}

/* For address alignment dependent on LTR or RTL scripts */
address div.left {
  text-align: left;
}
address div.right {
  text-align: right;
}

/* Provide table alignment support.  We can't use the alignX classes above
   since they do unwanted things with caption and other styling. */
table.right {
 margin-left: auto;
 margin-right: 0;
}
table.center {
 margin-left: auto;
 margin-right: auto;
}
table.left {
 margin-left: 0;
 margin-right: auto;
}

/* Give the table caption label the same styling as the figcaption */
caption a[href] {
  color: #222;
}

@media print {
  .toplink {
    display: none;
  }

  /* avoid overwriting the top border line with the ToC header */
  #toc {
    padding-top: 1px;
  }

  /* Avoid page breaks inside dl and author address entries */
  .vcard {
    page-break-inside: avoid;
  }

}
/* Avoid wrapping of URLs in references */
@media screen {
  .references a {
    white-space: nowrap;
  }
}
/* Tweak the bcp14 keyword presentation */
.bcp14 {
  font-variant: small-caps;
  font-weight: bold;
  font-size: 0.9em;
}
/* Tweak the invisible space above H* in order not to overlay links in text above */
 h2 {
  margin-top: -18px;  /* provide offset for in-page anchors */
  padding-top: 31px;
 }
 h3 {
  margin-top: -18px;  /* provide offset for in-page anchors */
  padding-top: 24px;
 }
 h4 {
  margin-top: -18px;  /* provide offset for in-page anchors */
  padding-top: 24px;
 }
/* Float artwork pilcrow to the right */
@media screen {
  .artwork a.pilcrow {
    display: block;
    line-height: 0.7;
    margin-top: 0.15em;
  }
}
/* Make pilcrows on dd visible */
@media screen {
  dd:hover > a.pilcrow {
    visibility: visible;
  }
}
/* Make the placement of figcaption match that of a table's caption
   by removing the figure's added bottom margin */
.alignLeft.art-text,
.alignCenter.art-text,
.alignRight.art-text {
   margin-bottom: 0;
}
.alignLeft,
.alignCenter,
.alignRight {
  margin: 1em 0 0 0;
}
/* In print, the pilcrow won't show on hover, so prevent it from taking up space,
   possibly even requiring a new line */
@media print {
  a.pilcrow {
    display: none;
  }
}
/* Styling for the external metadata */
div#external-metadata {
  background-color: #eee;
  padding: 0.5em;
  margin-bottom: 0.5em;
  display: none;
}
div#internal-metadata {
  padding: 0.5em;                       /* to match the external-metadata padding */
}
/* Styling for title RFC Number */
h1#rfcnum {
  clear: both;
  margin: 0 0 -1em;
  padding: 1em 0 0 0;
}
/* Make .olPercent look the same as <ol><li> */
dl.olPercent > dd {
  margin-bottom: 0.25em;
  min-height: initial;
}
/* Give aside some styling to set it apart */
aside {
  border-left: 1px solid #ddd;
  margin: 1em 0 1em 2em;
  padding: 0.2em 2em;
}
aside > dl,
aside > ol,
aside > ul,
aside > table,
aside > p {
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<table class="ears">
<thead><tr>
<td class="left">RFC 8769</td>
<td class="center">CMS Content Types for CBOR</td>
<td class="right">March 2020</td>
</tr></thead>
<tfoot><tr>
<td class="left">Schaad</td>
<td class="center">Informational</td>
<td class="right">[Page]</td>
</tr></tfoot>
</table>
<div id="external-metadata" class="document-information"></div>
<div id="internal-metadata" class="document-information">
<dl id="identifiers">
<dt class="label-stream">Stream:</dt>
<dd class="stream">Internet Engineering Task Force (IETF)</dd>
<dt class="label-rfc">RFC:</dt>
<dd class="rfc"><a href="https://www.rfc-editor.org/rfc/rfc8769" class="eref">8769</a></dd>
<dt class="label-category">Category:</dt>
<dd class="category">Informational</dd>
<dt class="label-published">Published:</dt>
<dd class="published">
<time datetime="2020-03" class="published">March 2020</time>
    </dd>
<dt class="label-issn">ISSN:</dt>
<dd class="issn">2070-1721</dd>
<dt class="label-authors">Author:</dt>
<dd class="authors">
<div class="author">
      <div class="author-name">J. Schaad</div>
<div class="org">August Cellars</div>
</div>
</dd>
</dl>
</div>
<h1 id="rfcnum">RFC 8769</h1>
<h1 id="title">Cryptographic Message Syntax (CMS) Content Types for Concise Binary Object Representation (CBOR)</h1>
<section id="section-abstract">
      <h2 id="abstract"><a href="#abstract" class="selfRef">Abstract</a></h2>
<p id="section-abstract-1">
        Concise Binary Object Representation (CBOR) is becoming a widely used method of doing content encoding.
        The Cryptographic Message Syntax (CMS) is still a widely used method of doing message-based security.
        This document defines a set of content types for CMS that hold CBOR content.<a href="#section-abstract-1" class="pilcrow">¶</a></p>
</section>
<div id="status-of-memo">
<section id="section-boilerplate.1">
        <h2 id="name-status-of-this-memo">
<a href="#name-status-of-this-memo" class="section-name selfRef">Status of This Memo</a>
        </h2>
<p id="section-boilerplate.1-1">
            This document is not an Internet Standards Track specification; it is
            published for informational purposes.<a href="#section-boilerplate.1-1" class="pilcrow">¶</a></p>
<p id="section-boilerplate.1-2">
            This document is a product of the Internet Engineering Task Force
            (IETF).  It represents the consensus of the IETF community.  It has
            received public review and has been approved for publication by the
            Internet Engineering Steering Group (IESG).  Not all documents
            approved by the IESG are candidates for any level of Internet
            Standard; see Section 2 of RFC 7841.<a href="#section-boilerplate.1-2" class="pilcrow">¶</a></p>
<p id="section-boilerplate.1-3">
            Information about the current status of this document, any
            errata, and how to provide feedback on it may be obtained at
            <span><a href="https://www.rfc-editor.org/info/rfc8769">https://www.rfc-editor.org/info/rfc8769</a></span>.<a href="#section-boilerplate.1-3" class="pilcrow">¶</a></p>
</section>
</div>
<div id="copyright">
<section id="section-boilerplate.2">
        <h2 id="name-copyright-notice">
<a href="#name-copyright-notice" class="section-name selfRef">Copyright Notice</a>
        </h2>
<p id="section-boilerplate.2-1">
            Copyright (c) 2020 IETF Trust and the persons identified as the
            document authors. All rights reserved.<a href="#section-boilerplate.2-1" class="pilcrow">¶</a></p>
<p id="section-boilerplate.2-2">
            This document is subject to BCP 78 and the IETF Trust's Legal
            Provisions Relating to IETF Documents
            (<span><a href="https://trustee.ietf.org/license-info">https://trustee.ietf.org/license-info</a></span>) in effect on the date of
            publication of this document. Please review these documents
            carefully, as they describe your rights and restrictions with
            respect to this document. Code Components extracted from this
            document must include Simplified BSD License text as described in
            Section 4.e of the Trust Legal Provisions and are provided without
            warranty as described in the Simplified BSD License.<a href="#section-boilerplate.2-2" class="pilcrow">¶</a></p>
</section>
</div>
<div id="toc">
<section id="section-toc.1">
        <a href="#" onclick="scroll(0,0)" class="toplink">▲</a><h2 id="name-table-of-contents">
<a href="#name-table-of-contents" class="section-name selfRef">Table of Contents</a>
        </h2>
<nav class="toc"><ul class="toc ulEmpty">
<li class="toc ulEmpty" id="section-toc.1-1.1">
            <p id="section-toc.1-1.1.1"><a href="#section-1" class="xref">1</a>.  <a href="#name-introduction" class="xref">Introduction</a><a href="#section-toc.1-1.1.1" class="pilcrow">¶</a></p>
</li>
<li class="toc ulEmpty" id="section-toc.1-1.2">
            <p id="section-toc.1-1.2.1"><a href="#section-2" class="xref">2</a>.  <a href="#name-cbor-content-type" class="xref">CBOR Content Type</a><a href="#section-toc.1-1.2.1" class="pilcrow">¶</a></p>
</li>
<li class="toc ulEmpty" id="section-toc.1-1.3">
            <p id="section-toc.1-1.3.1"><a href="#section-3" class="xref">3</a>.  <a href="#name-cbor-sequence-content-type" class="xref">CBOR Sequence Content Type</a><a href="#section-toc.1-1.3.1" class="pilcrow">¶</a></p>
</li>
<li class="toc ulEmpty" id="section-toc.1-1.4">
            <p id="section-toc.1-1.4.1"><a href="#section-4" class="xref">4</a>.  <a href="#name-asn1-module" class="xref">ASN.1 Module</a><a href="#section-toc.1-1.4.1" class="pilcrow">¶</a></p>
</li>
<li class="toc ulEmpty" id="section-toc.1-1.5">
            <p id="section-toc.1-1.5.1"><a href="#section-5" class="xref">5</a>.  <a href="#name-iana-considerations" class="xref">IANA Considerations</a><a href="#section-toc.1-1.5.1" class="pilcrow">¶</a></p>
</li>
<li class="toc ulEmpty" id="section-toc.1-1.6">
            <p id="section-toc.1-1.6.1"><a href="#section-6" class="xref">6</a>.  <a href="#name-security-considerations" class="xref">Security Considerations</a><a href="#section-toc.1-1.6.1" class="pilcrow">¶</a></p>
</li>
<li class="toc ulEmpty" id="section-toc.1-1.7">
            <p id="section-toc.1-1.7.1"><a href="#section-7" class="xref">7</a>.  <a href="#name-normative-references" class="xref">Normative References</a><a href="#section-toc.1-1.7.1" class="pilcrow">¶</a></p>
</li>
<li class="toc ulEmpty" id="section-toc.1-1.8">
            <p id="section-toc.1-1.8.1"><a href="#section-appendix.a" class="xref"></a><a href="#name-authors-address" class="xref">Author's Address</a><a href="#section-toc.1-1.8.1" class="pilcrow">¶</a></p>
</li>
</ul>
</nav>
</section>
</div>
<section id="section-1">
      <h2 id="name-introduction">
<a href="#section-1" class="section-number selfRef">1. </a><a href="#name-introduction" class="section-name selfRef">Introduction</a>
      </h2>
<p id="section-1-1">
        Concise Binary Object Representation (CBOR) <span>[<a href="#RFC7049" class="xref">CBOR</a>]</span>
 is a compact self-describing binary encoding formation that is
 starting to be used in many different applications.
        One of the primary uses of CBOR is in the Internet of Things, the
 constrained nature of which means that having minimal size of
 encodings becomes very important.
        The Cryptographic Message Syntax (CMS) <span>[<a href="#RFC5652" class="xref">CMS</a>]</span> is still one of the most common methods for
 providing message-based security, although in many cases, the CBOR
 Object Signing and Encryption (COSE) <span>[<a href="#RFC8152" class="xref">COSE</a>]</span>
 message-based security system is starting to be used.
        Given that CBOR is going to be transported using CMS, it makes sense
 to define CMS content types for the purpose of denoting that the
 embedded content is CBOR.
        This document defines two new content types: CBOR content type and
 CBOR Sequence content type <span>[<a href="#RFC8742" class="xref">CBOR-SEQ</a>]</span>.<a href="#section-1-1" class="pilcrow">¶</a></p>
</section>
<section id="section-2">
      <h2 id="name-cbor-content-type">
<a href="#section-2" class="section-number selfRef">2. </a><a href="#name-cbor-content-type" class="section-name selfRef">CBOR Content Type</a>
      </h2>
<p id="section-2-1">
        <span>[<a href="#RFC7049" class="xref">CBOR</a>]</span> defines an encoded CBOR item.
        This section defines a new content type for wrapping an encoded CBOR item in a CMS object.<a href="#section-2-1" class="pilcrow">¶</a></p>
<p id="section-2-2">
        The following object identifier identifies the CBOR content type:<a href="#section-2-2" class="pilcrow">¶</a></p>
<div id="section-2-3">
<pre class="sourcecode lang-asn.1">
id-ct-cbor OBJECT IDENTIFIER ::= { iso(1) member-body(2) usa(840)
        rsadsi(113549) pkcs(1) pkcs9(9) smime(16) ct(1) 44 }
</pre><a href="#section-2-3" class="pilcrow">¶</a>
</div>
<p id="section-2-4">
        The CBOR content type is intended to refer to a single object encoded using the CBOR encoding format <span>[<a href="#RFC7049" class="xref">CBOR</a>]</span>.
        Nothing is stated about the specific CBOR object that is included.
        CBOR can always be decoded to a tree, as the encoding is self descriptive.<a href="#section-2-4" class="pilcrow">¶</a></p>
<p id="section-2-5">
        The CBOR content type is intended to be encapsulated in the signed
 data and auth-enveloped data, but it can be included in any CMS wrapper.
        It cannot be predicted whether the compressed CMS encapsulation will
 provide compression, because the content may be binary rather than text.<a href="#section-2-5" class="pilcrow">¶</a></p>
<p id="section-2-6">
        <span>[<a href="#RFC7193" class="xref">RFC7193</a>]</span> defined an optional parameter,
 "innerContent", to allow for identification of what the inner content
 is for an application/cms media type.
        This document defines the string "cbor" as a new value that can be
 placed in this parameter when a CBOR content type is used.<a href="#section-2-6" class="pilcrow">¶</a></p>
</section>
<section id="section-3">
      <h2 id="name-cbor-sequence-content-type">
<a href="#section-3" class="section-number selfRef">3. </a><a href="#name-cbor-sequence-content-type" class="section-name selfRef">CBOR Sequence Content Type</a>
      </h2>
<p id="section-3-1">
        <span>[<a href="#RFC8742" class="xref">CBOR-SEQ</a>]</span> defines a CBOR Sequence as a concatenation of zero or more CBOR objects.
        This section defines a new content type for wrapping a CBOR Sequence in a CMS object.<a href="#section-3-1" class="pilcrow">¶</a></p>
<p id="section-3-2">
        The following object identifier identifies the CBOR Sequence content type:<a href="#section-3-2" class="pilcrow">¶</a></p>
<div id="section-3-3">
<pre class="sourcecode lang-asn.1">
id-ct-cborSequence OBJECT IDENTIFIER ::= { iso(1) member-body(2)
        usa(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) ct(1)
        45 }
</pre><a href="#section-3-3" class="pilcrow">¶</a>
</div>
<p id="section-3-4">
        The CBOR Sequence content type is intended to refer to a sequence of objects encoded using the CBOR encoding format.
        The objects are concatenated without any markers delimiting the individual CBOR objects.
        Nothing is stated about the specific CBOR objects that are included.
        CBOR can always be decoded to a tree, because the encoding is self descriptive.<a href="#section-3-4" class="pilcrow">¶</a></p>
<p id="section-3-5">
        The CBOR Sequence content type is intended to be encapsulated in the
 signed data and auth-enveloped data, but it can be included in any CMS
 wrapper. It cannot be predicted whether the compressed CMS encapsulation will
 provide compression, because the content may be binary rather than text.<a href="#section-3-5" class="pilcrow">¶</a></p>
<p id="section-3-6">
        <span>[<a href="#RFC7193" class="xref">RFC7193</a>]</span> defined an optional parameter, "innerContent", to allow for identification of what the inner content is for an application/cms media type.
        This document defines the string "cborSequence" as a new value that
 can be placed in this parameter when a CBOR Sequence content type is used.<a href="#section-3-6" class="pilcrow">¶</a></p>
</section>
<section id="section-4">
      <h2 id="name-asn1-module">
<a href="#section-4" class="section-number selfRef">4. </a><a href="#name-asn1-module" class="section-name selfRef">ASN.1 Module</a>
      </h2>
<div id="section-4-1">
<pre class="sourcecode lang-asn.1">
CborContentTypes { iso(1) member-body(2) usa(840)
        rsadsi(113549) pkcs(1) pkcs9(9) smime(16) modules(0)
        id-mod-cbor-2019(71) }
DEFINITIONS EXPLICIT TAGS ::= BEGIN

IMPORTS
    CONTENT-TYPE
    FROM  CryptographicMessageSyntax-2010
      { iso(1) member-body(2) us(840) rsadsi(113549)
         pkcs(1) pkcs-9(9) smime(16) modules(0) id-mod-cms-2009(58) }
    ;

    id-ct-cbor OBJECT IDENTIFIER ::= { iso(1) member-body(2)
        us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) ct(1)
        44 }

    id-ct-cborSequence OBJECT IDENTIFIER ::= { iso(1) member-body(2)
        us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) ct(1)
        45 }

    -- Content is encoded directly and does not have any ASN.1
    --    structure
    ct-Cbor CONTENT-TYPE ::= { IDENTIFIED BY id-ct-cbor }

    -- Content is encoded directly and does not have any ASN.1
    --    structure
    ct-CborSequence CONTENT-TYPE ::= {
        IDENTIFIED BY id-ct-cborSequence
    }

END
</pre><a href="#section-4-1" class="pilcrow">¶</a>
</div>
</section>
<section id="section-5">
      <h2 id="name-iana-considerations">
<a href="#section-5" class="section-number selfRef">5. </a><a href="#name-iana-considerations" class="section-name selfRef">IANA Considerations</a>
      </h2>
<p id="section-5-1">
        IANA has registered the following in the "SMI Security for S/MIME
 Module Identifier (1.2.840.113549.1.9.16.0)" subregistry within the
 SMI Numbers registry:<a href="#section-5-1" class="pilcrow">¶</a></p>
<table class="center" id="table-1">
        <caption><a href="#table-1" class="selfRef">Table 1</a></caption>
<thead>
          <tr>
            <th class="text-left" rowspan="1" colspan="1">Decimal</th>
            <th class="text-left" rowspan="1" colspan="1">Description</th>
            <th class="text-left" rowspan="1" colspan="1">References</th>
          </tr>
        </thead>
        <tbody>
          <tr>
            <td class="text-left" rowspan="1" colspan="1">71</td>
            <td class="text-left" rowspan="1" colspan="1">id-mod-cbor-2019</td>
            <td class="text-left" rowspan="1" colspan="1">RFC 8769</td>
          </tr>
        </tbody>
      </table>
<p id="section-5-3">
        IANA has registered the following in the
 "SMI Security for S/MIME CMS Content Type (1.2.840.113549.1.9.16.1)"
 subregistry within the SMI Numbers registry:<a href="#section-5-3" class="pilcrow">¶</a></p>
<table class="center" id="table-2">
        <caption><a href="#table-2" class="selfRef">Table 2</a></caption>
<thead>
          <tr>
            <th class="text-left" rowspan="1" colspan="1">Decimal</th>
            <th class="text-left" rowspan="1" colspan="1">Description</th>
            <th class="text-left" rowspan="1" colspan="1">References</th>
          </tr>
        </thead>
        <tbody>
          <tr>
            <td class="text-left" rowspan="1" colspan="1">44</td>
            <td class="text-left" rowspan="1" colspan="1">id-ct-cbor</td>
            <td class="text-left" rowspan="1" colspan="1">RFC 8769</td>
          </tr>
          <tr>
            <td class="text-left" rowspan="1" colspan="1">45</td>
            <td class="text-left" rowspan="1" colspan="1">id-ct-cborSequence</td>
            <td class="text-left" rowspan="1" colspan="1">RFC 8769</td>
          </tr>
        </tbody>
      </table>
<p id="section-5-5">
        IANA has registered the following in the "CMS Inner Content Types"
 subregistry within the "MIME Media Type Sub-Parameter Registries":<a href="#section-5-5" class="pilcrow">¶</a></p>
<table class="center" id="table-3">
        <caption><a href="#table-3" class="selfRef">Table 3</a></caption>
<thead>
          <tr>
            <th class="text-left" rowspan="1" colspan="1">Name</th>
            <th class="text-left" rowspan="1" colspan="1">Object Identifier</th>
            <th class="text-left" rowspan="1" colspan="1">Reference</th>
          </tr>
        </thead>
        <tbody>
          <tr>
            <td class="text-left" rowspan="1" colspan="1">cbor</td>
            <td class="text-left" rowspan="1" colspan="1">1.2.840.113549.1.9.16.1.44</td>
            <td class="text-left" rowspan="1" colspan="1">RFC 8769</td>
          </tr>
          <tr>
            <td class="text-left" rowspan="1" colspan="1">cborSequence</td>
            <td class="text-left" rowspan="1" colspan="1">1.2.840.113549.1.9.16.1.45</td>
            <td class="text-left" rowspan="1" colspan="1">RFC 8769</td>
          </tr>
        </tbody>
      </table>
</section>
<section id="section-6">
      <h2 id="name-security-considerations">
<a href="#section-6" class="section-number selfRef">6. </a><a href="#name-security-considerations" class="section-name selfRef">Security Considerations</a>
      </h2>
<p id="section-6-1">
        This document only provides identification for content types; it does
 not introduce any new security issues by itself.
        The new content types mean that id-data does not need to be used to
 identify these content types; they can therefore reduce confusion.<a href="#section-6-1" class="pilcrow">¶</a></p>
</section>
<section id="section-7">
      <h2 id="name-normative-references">
<a href="#section-7" class="section-number selfRef">7. </a><a href="#name-normative-references" class="section-name selfRef">Normative References</a>
      </h2>
<dl class="references">
<dt id="RFC7049">[CBOR]</dt>
<dd>
<span class="refAuthor">Bormann, C.</span><span class="refAuthor"> and P. Hoffman</span>, <span class="refTitle">"Concise Binary Object Representation (CBOR)"</span>, <span class="seriesInfo">RFC 7049</span>, <span class="seriesInfo">DOI 10.17487/RFC7049</span>, <time datetime="2013-10">October 2013</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc7049">https://www.rfc-editor.org/info/rfc7049</a>&gt;</span>. </dd>
<dt id="RFC8742">[CBOR-SEQ]</dt>
<dd>
<span class="refAuthor">Bormann, C.</span>, <span class="refTitle">"Concise Binary Object Representation (CBOR) Sequences"</span>, <span class="seriesInfo">RFC 8742</span>, <span class="seriesInfo">DOI 10.17487/RFC8742</span>, <time datetime="2020-02">February 2020</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8742">https://www.rfc-editor.org/info/rfc8742</a>&gt;</span>. </dd>
<dt id="RFC5652">[CMS]</dt>
<dd>
<span class="refAuthor">Housley, R.</span>, <span class="refTitle">"Cryptographic Message Syntax (CMS)"</span>, <span class="seriesInfo">STD 70</span>, <span class="seriesInfo">RFC 5652</span>, <span class="seriesInfo">DOI 10.17487/RFC5652</span>, <time datetime="2009-09">September 2009</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5652">https://www.rfc-editor.org/info/rfc5652</a>&gt;</span>. </dd>
<dt id="RFC8152">[COSE]</dt>
<dd>
<span class="refAuthor">Schaad, J.</span>, <span class="refTitle">"CBOR Object Signing and Encryption (COSE)"</span>, <span class="seriesInfo">RFC 8152</span>, <span class="seriesInfo">DOI 10.17487/RFC8152</span>, <time datetime="2017-07">July 2017</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8152">https://www.rfc-editor.org/info/rfc8152</a>&gt;</span>. </dd>
<dt id="RFC7193">[RFC7193]</dt>
<dd>
<span class="refAuthor">Turner, S.</span><span class="refAuthor">, Housley, R.</span><span class="refAuthor">, and J. Schaad</span>, <span class="refTitle">"The application/cms Media Type"</span>, <span class="seriesInfo">RFC 7193</span>, <span class="seriesInfo">DOI 10.17487/RFC7193</span>, <time datetime="2014-04">April 2014</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc7193">https://www.rfc-editor.org/info/rfc7193</a>&gt;</span>. </dd>
</dl>
</section>
<div id="authors-addresses">
<section id="section-appendix.a">
      <h2 id="name-authors-address">
<a href="#name-authors-address" class="section-name selfRef">Author's Address</a>
      </h2>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Jim Schaad</span></div>
<div dir="auto" class="left"><span class="org">August Cellars</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:ietf@augustcellars.com" class="email">ietf@augustcellars.com</a>
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</address>
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