<?xmlversion="1.0" encoding="US-ASCII"?>version='1.0' encoding='utf-8'?> <!DOCTYPE rfc SYSTEM"rfc2629.dtd" [ <!-- One method to get references from the online citation libraries. There has to be one entity for each item to be referenced. An alternate method (rfc include) is described in the references. --> <!ENTITY RFC2119 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2119.xml"> <!ENTITY RFC8174 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.8174.xml"> <!--<!ENTITY RFC5226 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.5226.xml"> --> <!ENTITY RFC4345 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.4345.xml"> <!ENTITY RFC4253 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.4253.xml"> <!ENTITY RFC7465 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.7465.xml"> <!ENTITY RFC8429 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.8429.xml"> ]>"rfc2629-xhtml.ent"> <?xml-stylesheet type='text/xsl' href='rfc2629.xslt' ?><!-- used by XSLT processors --> <!-- For a complete list and description of processing instructions (PIs), please see http://xml.resource.org/authoring/README.html. --> <!-- Below are generally applicable Processing Instructions (PIs) that most I-Ds might want to use. (Here they are set differently than their defaults in xml2rfc v1.32) --> <?rfc strict="yes" ?> <!-- give errors regarding ID-nits and DTD validation --> <!-- control the table of contents (ToC) --> <?rfc toc="yes"?> <!-- generate a ToC --> <?rfc tocdepth="4"?> <!-- the number of levels of subsections in ToC. default: 3 --> <!-- control references --> <?rfc symrefs="yes"?> <!-- use symbolic references tags, i.e, [RFC2119] instead of [1] --> <?rfc sortrefs="yes" ?> <!-- sort the reference entries alphabetically --> <!-- control vertical white space (using these PIs as follows is recommended by the RFC Editor) --> <?rfc compact="yes" ?> <!-- do not start each main section on a new page --> <?rfc subcompact="no" ?> <!-- keep one blank line between list items --> <!-- end of list of popular I-D processing instructions --><rfc xmlns:xi="http://www.w3.org/2001/XInclude" category="bcp" updates="4253" docName="draft-ietf-curdle-rc4-die-die-die-18"ipr="trust200902">ipr="trust200902" obsoletes="" submissionType="IETF" xml:lang="en" tocInclude="true" tocDepth="4" symRefs="true" sortRefs="true" version="3" number="8758" consensus="true" > <!--category values: std, bcp, info, exp, and historic ipr values: trust200902, noModificationTrust200902, noDerivativesTrust200902, or pre5378Trust200902 you can add the attributes updates="NNNN" and obsoletes="NNNN" they will automatically be output with "(if approved)" --> <!-- ***** FRONT MATTER *****xml2rfc v2v3 conversion 2.40.1 --> <front><!-- The abbreviated title is used in the page header - it is only necessary if the full title is longer than 39 characters --><titleabbrev="draft-ietf-curdle-rc4-die-die-die">Deprecatingabbrev="Deprecating RC4 in SSH">Deprecating RC4 in Secure Shell (SSH)</title><!-- add 'role="editor"' below for the editors if appropriate --> <!-- Another author who claims to be an editor --><seriesInfo name="RFC" value="8758"/> <seriesInfo name="BCP" value="227"/> <author fullname="Loganaden Velvindron"initials="L.V."initials="L." surname="Velvindron"> <organization>cyberstorm.mu</organization> <address> <postal><street></street> <!-- Reorder these if your country does things differently --> <city></city> <region></region> <code></code><street/> <city/> <region/> <code/> <country>Mauritius</country> </postal><phone></phone><phone/> <email>logan@cyberstorm.mu</email><!-- uri and facsimile elements may also be added --></address> </author> <dateyear="2019" /> <!-- Meta-data Declarationsyear="2020" month="April"/> <area>Security</area> <workgroup>curdle</workgroup> <!-- [rfced] Please insert any keywords (beyond those that appear in the title) for use on https://www.rfc-editor.org/search. --><area>General</area> <workgroup>Internet Engineering Task Force</workgroup><keyword>example</keyword> <!--WG name at[rfced] When version 16 was approved, theupperleft corner ofauthors indicated there might be some updates needed to address IESG comments. We assume these have been addressed in thedoc, IETF is fine for individual submissions.updated versions. If thiselementisnot present, the default is "Network Working Group", which is used by the RFC Editor as a nod to the history of the IETF. --> <keyword>template</keyword> <!-- Keywords will be incorporated into HTML output files in a meta tag but they have no effect on textincorrect, please either send along changes ornroff output. If you submit your draft to the RFC Editor, the keywords will be used forupdate thesearch engine.XML file. --> <abstract><t> This<t>This document deprecates RC4 in Secure Shell (SSH). Therefore, this document formally movesRFC4345RFC 4345 tohistoricHistoric status. </t> </abstract> </front> <middle> <sectiontitle="Introduction">numbered="true" toc="default"> <name>Introduction</name> <t>The usage of RC4 suites( also(also designated asarcfour )"arcfour") for SSHareis specified in <xreftarget="RFC4253"></xref>target="RFC4253" format="default"/> and <xreftarget="RFC4345"></xref>.target="RFC4345" format="default"/>. <xreftarget="RFC4253"></xref>target="RFC4253" format="default"/> specifies the allocation of the "arcfour" cipher for SSH. <xreftarget="RFC4345"></xref>target="RFC4345" format="default"/> specifies and allocates the "arcfour128" and "arcfour256" ciphers for SSH. RC4 encryption has known weaknesses <xreftarget="RFC7465"></xref>target="RFC7465" format="default"/> <xreftarget="RFC8429"></xref>, andtarget="RFC8429" format="default"/>; therefore, this document starts the deprecation processshould be begunfor their use in Secure Shell (SSH) <xreftarget="RFC4253"></xref>.target="RFC4253" format="default"/>. Accordingly, <xreftarget="RFC4253"></xref>target="RFC4253" format="default"/> is updated to note the deprecation of the RC4ciphersciphers, and <xreftarget="RFC4345"></xref>target="RFC4345" format="default"/> is moved to Historic status, as all ciphers it specifiesMUST NOT<bcp14>MUST NOT</bcp14> be used. </t> <sectiontitle="Requirements Language"> <t>Thenumbered="true" toc="default"> <name>Requirements Language</name> <t> The key words"MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY","<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>", "<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>", "<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>", "<bcp14>MAY</bcp14>", and"OPTIONAL""<bcp14>OPTIONAL</bcp14>" in this document are to be interpreted as described in BCP 14 <xref target="RFC2119"/> <xreftarget="RFC2119">RFC 2119</xref><xref target="RFC8174">RFC 8174</xref>target="RFC8174"/> when, and only when, they appear in all capitals, as shownhere.</t>here. </t> </section> </section> <sectiontitle="Updatesnumbered="true" toc="default"> <name>Updates to RFC4253">4253</name> <t> <xreftarget="RFC4253"></xref>target="RFC4253" format="default"/> is updated to prohibit arcfour's use in SSH. <xreftarget="RFC4253"></xref>target="RFC4253" sectionFormat="comma" section="6.3"/> allocates the "arcfour" cipherin Section 6.3by defining a list of defined cipherswherein which the "arcfour" cipher appears asoptionaloptional, asmentioned below:shown in <xref target="OPTIONAL" />. </t><texttable> <ttcol ></ttcol> <ttcol ></ttcol> <ttcol ></ttcol> <c>arcfour </c> <c>OPTIONAL </c> <c>the<table align="center" anchor="OPTIONAL"> <tbody> <tr> <td align="left">arcfour</td> <td align="left"><bcp14>OPTIONAL</bcp14></td> <td align="left">the ARCFOUR stream cipher with a 128-bitkey </c> </texttable>key</td> </tr> </tbody> </table> <t> Thiscurrentdocument updates the status of the "arcfour" ciphers in the listoffound in <xreftarget="RFC4253"></xref> Section 6.3target="RFC4253" sectionFormat="comma" section="6.3"/> by moving it fromOPTIONAL<bcp14>OPTIONAL</bcp14> toMUST NOT.<bcp14>MUST NOT</bcp14>. </t><texttable> <ttcol ></ttcol> <ttcol ></ttcol> <ttcol ></ttcol> <c><table align="center"> <tbody> <tr> <td align="left"> arcfour</c> <c>MUST NOT </c> <c></td> <td align="left"><bcp14>MUST NOT</bcp14> </td> <td align="left"> the ARCFOUR stream cipher with a 128-bitkey</c> </texttable>key</td> </tr> </tbody> </table> <t> <xreftarget="RFC4253"></xref>target="RFC4253" format="default"/> defines the "arcfour" ciphers with thetext mentioned below:following text: </t><t><blockquote> The "arcfour" cipher is the Arcfour stream cipher with 128-bit keys. The Arcfour cipher is believed to be compatible with the RC4 cipher <xreftarget= "SCHNEIER"></xref>.target="SCHNEIER" format="default"/>. Arcfour (and RC4) has problems with weak keys, and should be used withcaution. </t>caution.</blockquote> <t> Thiscurrentdocument updates <xreftarget="RFC4253"></xref> Section 6.3target="RFC4253" sectionFormat="comma" section="6.3"/> by replacing the text above with the following text: </t><t><blockquote> The "arcfour" cipher is the Arcfour stream cipher with 128-bit keys. The Arcfour cipher is compatible with the RC4 cipher <xreftarget= "SCHNEIER"></xref>.target="SCHNEIER" format="default"/>. Arcfour (and RC4) has known weaknesses <xreftarget="RFC7465"></xref>target="RFC7465" format="default"/> <xreftarget="RFC8429"></xref>,target="RFC8429" format="default"/> andMUST NOT<bcp14>MUST NOT</bcp14> be used.</t></blockquote> </section><!-- Possibly a 'Contributors' section ... --><sectiontitle="IANA Considerations">numbered="true" toc="default"> <name>IANA Considerations</name> <t>The IANAis requested to updatehas updated theEncryption"Encryption AlgorithmName Registry ofNames" subregistry in theSecure"Secure Shell (SSH) ProtocolParametersParameters" registry <xreftarget="IANA"/>.target="IANA" format="default"/>. TheRegistrationregistration procedure is IETFReviewreview, which is achieved by this document. The registryshould behas been updated as follows:</t><texttable> <ttcol>Encryption<table align="center"> <thead> <tr> <th align="left">Encryption AlgorithmName </ttcol> <ttcol> Reference</ttcol> <ttcol> Note</ttcol> <c>arcfour</c> <c> [RFC-TBD]</c> <c> </c> <c>arcfour128 </c> <c> [RFC-TBD] </c> <c> </c> <c>arcfour256 </c> <c> [RFC-TBD] </c> <c> </c> </texttable> <t>Where TBD is the RFC number assigned to the document. </t> <!-- <t>All drafts are required to have an IANA considerations section (see <xref target="RFC5226">Guidelines for Writing an IANA Considerations Section in RFCs</xref> for a guide). If the draft does not require IANA to do anything, the section contains an explicit statement that this is the case (as above). If there are no requirements for IANA, the section will be removed during conversion into an RFC by the RFC Editor.</t> --> </section> <section anchor="Acknowledgements" title="Acknowledgements"> <t>The authors would like to thank Eric Rescorla, Daniel Migault and Rich Salz. </t>Name</th> <th align="left">Reference</th> <th align="left">Note</th> </tr> </thead> <tbody> <tr> <td align="left">arcfour</td> <td align="left">RFC 8758</td> <td align="left">HISTORIC</td> </tr> <tr> <td align="left">arcfour128 </td> <td align="left">RFC 8758</td> <td align="left">HISTORIC</td> </tr> <tr> <td align="left">arcfour256 </td> <td align="left">RFC 8758</td> <td align="left">HISTORIC</td> </tr> </tbody> </table> </section> <section anchor="Security"title="Security Considerations">numbered="true" toc="default"> <name>Security Considerations</name> <t>This document only prohibits the use of RC4 inSSH, andSSH; it introduces no new security considerations.</t> </section> </middle> <!-- *****BACK MATTER ***** --> <back><!-- References split into informative and normative --> <references title="Normative References"> <!--?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.2119.xml"?--> &RFC2119; <!--?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.8174.xml"?--> &RFC8174;<references> <name>References</name> <references> <name>Normative References</name> <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.2119.xml"/> <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8174.xml"/> </references><references title="Informative References"> <!-- Here we use entities that we defined at the beginning. --> <!--&RFC5226;--> &RFC4345; &RFC4253; &RFC7465; &RFC8429; <!-- A reference written by by an organization not a person. --><references> <name>Informative References</name> <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.4345.xml"/> <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.4253.xml"/> <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.7465.xml"/> <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8429.xml"/> <reference anchor="SCHNEIER"target="SCHNEIER">target=""> <front> <title>Applied Cryptography Second Edition:protocols algorithmsProtocols, Algorithms, andsourceSource incodeCode in C </title> <seriesInfo name="John Wiley and Sons" value="New York, NY"/> <authorinitials="B.S"initials="B." surname="Schneier" fullname="Bruce Schneier"><organization /><organization/> </author> <date month=""year="1996" />year="1996"/> </front><seriesInfo name="" value="" /></reference> <reference anchor="IANA"target="https://www.iana.org/assignments/ssh-parameters/ssh-parameters.xhtml#ssh-parameters-17">target="https://www.iana.org/assignments/ssh-parameters"> <front> <title>Secure Shell (SSH) ProtocolParameters: Encryption Algorithm Names</title>Parameters</title> <author/><date/></front> </reference> </references><!-- Change Log v08 update email address. v07 reproduce -06 of luis' draft + update with daniel's comments --></references> <section anchor="Acknowledgements" numbered="false" toc="default"> <name>Acknowledgements</name> <t>The author would like to thank <contact fullname="Eric Rescorla"/>, <contact fullname="Daniel Migault"/>, and <contact fullname="Rich Salz"/>.</t> </section> </back> </rfc>