diff options
| author | Christian Pointner <equinox@anytun.org> | 2008-04-20 23:27:26 +0000 |
|---|---|---|
| committer | Christian Pointner <equinox@anytun.org> | 2008-04-20 23:27:26 +0000 |
| commit | 50151aa476b22f5797c890e28993bd88c0f7a710 (patch) | |
| tree | 85d2a7380e817e4de3c4d7946881a78f19f41f64 /papers/draft-gsenger-secure-anycast-tunneling-protocol-02.html | |
| parent | fixed init script (diff) | |
fixed some spelling errors @ internet draft
Diffstat (limited to 'papers/draft-gsenger-secure-anycast-tunneling-protocol-02.html')
| -rw-r--r-- | papers/draft-gsenger-secure-anycast-tunneling-protocol-02.html | 48 |
1 files changed, 24 insertions, 24 deletions
diff --git a/papers/draft-gsenger-secure-anycast-tunneling-protocol-02.html b/papers/draft-gsenger-secure-anycast-tunneling-protocol-02.html index 80ab6c9..68cd3e4 100644 --- a/papers/draft-gsenger-secure-anycast-tunneling-protocol-02.html +++ b/papers/draft-gsenger-secure-anycast-tunneling-protocol-02.html @@ -147,7 +147,7 @@ <tr><td class="header">Intended status: Informational</td><td class="header"> </td></tr> <tr><td class="header">Expires: July 4, 2008</td><td class="header"> </td></tr> </table></td></tr></table> -<h1><br />secure anycast tunneling protocol (SATP)<br />draft-gsenger-secure-anycast-tunneling-protocol-01</h1> +<h1><br />secure anycast tunneling protocol (SATP)<br />draft-gsenger-secure-anycast-tunneling-protocol-02</h1> <h3>Status of this Memo</h3> <p> @@ -181,7 +181,7 @@ Copyright © The Internet Society (2008).</p> <h3>Abstract</h3> -<p>The secure anycast tunneling protocol (SATP) defines a protocol used for communication between any combination of unicast and anycast tunnel endpoints. It allows tunneling of every ETHER TYPE protocol (ethernet, ip ...). SATP directly includes cryptography and message authentication based on the methodes used by SRTP. It can be used as an encrypted alternative to <a class='info' href='#RFC2003'>IP Encapsulation within IP<span> (</span><span class='info'>Perkins, C., “IP Encapsulation within IP,” October 1996.</span><span>)</span></a> [3] and <a class='info' href='#RFC2784'>Generic Routing Encapsulation (GRE)<span> (</span><span class='info'>Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. Traina, “Generic Routing Encapsulation (GRE),” March 2000.</span><span>)</span></a> [4]. It supports both anycast receivers and senders. +<p>The secure anycast tunneling protocol (SATP) defines a protocol used for communication between any combination of unicast and anycast tunnel endpoints. It allows tunneling of every ETHER TYPE protocol (ethernet, ip ...). SATP directly includes cryptography and message authentication based on the methods used by the <a class='info' href='#RFC3711'>Secure Real-time Transport Protocol(SRTP)<span> (</span><span class='info'>Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, “The Secure Real-time Transport Protocol (SRTP),” March 2004.</span><span>)</span></a> [1]. It can be used as an encrypted alternative to <a class='info' href='#RFC2003'>IP Encapsulation within IP<span> (</span><span class='info'>Perkins, C., “IP Encapsulation within IP,” October 1996.</span><span>)</span></a> [3] and <a class='info' href='#RFC2784'>Generic Routing Encapsulation (GRE)<span> (</span><span class='info'>Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. Traina, “Generic Routing Encapsulation (GRE),” March 2000.</span><span>)</span></a> [4]. Both anycast receivers and senders are supported. </p><a name="toc"></a><br /><hr /> <h3>Table of Contents</h3> @@ -219,7 +219,7 @@ sender ID<br /> <a href="#anchor16">4.4.</a> MUX<br /> <a href="#anchor17">4.5.</a> -payload type field<br /> +payload type<br /> <a href="#anchor18">4.6.</a> payload<br /> <a href="#anchor19">4.7.</a> @@ -256,8 +256,8 @@ Intellectual Property and Copyright Statements<br /> <a name="rfc.section.1"></a><h3>1. Introduction</h3> -<p>SATP is a mixture of a generic encapsulation protocol like <a class='info' href='#RFC2784'>GRE<span> (</span><span class='info'>Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. Traina, “Generic Routing Encapsulation (GRE),” March 2000.</span><span>)</span></a> [4] and a secure tunneling protocol as <a class='info' href='#RFC2401'>IPsec<span> (</span><span class='info'>Kent, S. and R. Atkinson, “Security Architecture for the Internet Protocol,” November 1998.</span><span>)</span></a> [5] in tunnel mode. It can be used to build redundant virtual private network (VPN) connections. It supports peer to peer tunnels, where tunnel endpoints can be any combination of unicast, multicast or anycast hosts, so it defines a <a class='info' href='#RFC1546'>Host Anycast Service<span> (</span><span class='info'>Partridge, C., Mendez, T., and W. Milliken, “Host Anycasting Service,” November 1993.</span><span>)</span></a> [6]. Encryption is done per packet, so the protocol is robust against packet loss and routing changes. - To save some header overhead it uses the encryption techniques of <a class='info' href='#RFC3711'>SRTP<span> (</span><span class='info'>Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, “The Secure Real-time Transport Protocol (SRTP),” March 2004.</span><span>)</span></a> [1]. +<p>SATP is a mixture of a generic encapsulation protocol like <a class='info' href='#RFC2784'>GRE<span> (</span><span class='info'>Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. Traina, “Generic Routing Encapsulation (GRE),” March 2000.</span><span>)</span></a> [4] and a secure tunneling protocol as <a class='info' href='#RFC2401'>IPsec<span> (</span><span class='info'>Kent, S. and R. Atkinson, “Security Architecture for the Internet Protocol,” November 1998.</span><span>)</span></a> [5] in tunnel mode. It can be used to build redundant virtual private network (VPN) connections. It supports peer-to-peer tunnels, where tunnel endpoints can be any combination of unicast, multicast or anycast hosts, so it defines a <a class='info' href='#RFC1546'>Host Anycast Service<span> (</span><span class='info'>Partridge, C., Mendez, T., and W. Milliken, “Host Anycasting Service,” November 1993.</span><span>)</span></a> [6]. Encryption is done per packet, so the protocol is robust against packet loss and routing changes. + To reduce header overhead ncryption techniques of <a class='info' href='#RFC3711'>SRTP<span> (</span><span class='info'>Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, “The Secure Real-time Transport Protocol (SRTP),” March 2004.</span><span>)</span></a> [1] are being used. </p> <a name="anchor2"></a><br /><hr /> @@ -272,7 +272,7 @@ Notational Conventions</h3> <a name="rfc.section.2"></a><h3>2. Motivation and usage scenarios</h3> -<p>This section gives an overview of possible usage scenarios. Please note, that the protocols used in the figures are only examples and that SATP itself does not care about either transport protocols or encapsulated protocols. Routing is not done by SATP and each implemetation MAY choose it's own way of doing this task (e.g. using functions provided by the operating system). SATP is used only to encapsulate and encrypt data. +<p>This section gives an overview of possible usage scenarios. Please note that the protocols used in the figures are only examples and that SATP itself does not care about either transport protocols or encapsulated protocols. Routing is not done by SATP and each implemetation MAY choose it's own way of doing this task (e.g. using functions provided by the operating system). SATP is used only to encapsulate and encrypt data. </p> <a name="anchor4"></a><br /><hr /> <table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table> @@ -299,7 +299,7 @@ Tunneling from unicast hosts over anycast routers to other unicast hosts</h3> endpoint | using SATP | endpoint | using SATP | endpoint </pre></div><table border="0" cellpadding="0" cellspacing="2" align="center"><tr><td align="center"><font face="monaco, MS Sans Serif" size="1"><b> Figure 1 </b></font><br /></td></tr></table><hr class="insert" /> -<p>In this scenario the payload gets encapsuleted into a SATP packet by a unicast host and gets transmitted to one of the anycast routers. It than gets decapsulated by the router. This router makes a routing descision based on the underlying protocol and transmits a new SATP package to one or more unicast hosts depending on the routing decision. +<p>In this scenario the payload is encapsuleted into a SATP packet by a unicast host and gets transmitted to one of the anycast routers. After transmisson the packet gets decapsulated by the router. This router makes a routing descision based on the underlying protocol and transmits a new SATP package to one or more unicast hosts depending on this decision. </p> <a name="anchor6"></a><br /><hr /> <table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table> @@ -328,7 +328,7 @@ Tunneling from unicast hosts to anycast networks</h3> </pre></div><table border="0" cellpadding="0" cellspacing="2" align="center"><tr><td align="center"><font face="monaco, MS Sans Serif" size="1"><b> Figure 2 </b></font><br /></td></tr></table><hr class="insert" /> -<p>When the unicast hosts wants to transmit data to one of the anycast DNS servers, it encapsulates the data and sends a SATP packet to the anycast address of the routers. The packet arrives at one of the routers, gets decapsulated and routed to the DNS server. This method can be used to tunnel between a clients and networks providing anycast services. It can also be used the other way to virtually locate a unicast service within anycasted networks. +<p>When the unicast hosts wants to transmit data to one of the anycast DNS servers, it encapsulates the data and sends a SATP packet to the anycast address of the routers. The packet arrives at one of the routers, gets decapsulated and is then forwarded to the DNS server. This method can be used to tunnel between clients and networks providing anycast services. It can also be used the other way to virtually locate a unicast service within anycasted networks. </p> <a name="anchor7"></a><br /><hr /> <table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table> @@ -352,14 +352,14 @@ Redundant tunnel connection of 2 networks</h3> </pre></div><table border="0" cellpadding="0" cellspacing="2" align="center"><tr><td align="center"><font face="monaco, MS Sans Serif" size="1"><b> Figure 3 </b></font><br /></td></tr></table><hr class="insert" /> -<p>Network A has multiple routers, that act as gateway/tunnel endpoints to another network B. This is done to build a redundant encrypted tunnel connection between the two networks. All tunnel endpoints of network A share the same anycast address and all tunnel endpoints of network B share another anycast address. When a packet from network A gets transmitted to network B, it first arrives on one of network A's border routers. Which router is used is determined by network A's internal routing. This router encapsulates the package and sends it to the anycast address of the network B routers. The SATP packet arrives at one of network B's routers and gets decapsulated and routed to it's destination within network B. +<p>Network A has multiple routers which act as gateway/tunnel endpoints to another network B. This way a redundant encrypted tunnel connection between the two networks is built up. All tunnel endpoints of network A share the same anycast address and all tunnel endpoints of network B share another anycast address. When a packet from network A is transmitted to network B, it first arrives on one of network A's border routers. Which router is used is determined by network A's internal routing. This router encapsulates the package and sends it to the anycast address of network B's routers. After arrival the SATP packet gets decapsulated and routed to its destination within network B. </p> <a name="anchor8"></a><br /><hr /> <table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table> <a name="rfc.section.2.2"></a><h3>2.2. Encapsulation</h3> -<p>SATP does not depend on which lower layer protocols is used, but this section gives an example of how packets could look like. +<p>SATP does not depend on which lower layer protocol is used. This section only gives an example of how packets could look like. </p><br /><hr class="insert" /> <a name="transport_udp"></a> @@ -410,10 +410,10 @@ Using SATP on top of IP</h3> Fragmentation</h3> <p> - The only way of fully supporting fragmentation would be to synchronise fragments between all anycast servers. This is considered to be too much overhead, so there are two non perfect solutions for these problems. Either fragmentation HAS TO be disabled or if not all fragments arrive at the same server the ip datagramm HAS TO be discarded. As routing changes are not expected to occure very frequently, the encapsulated protocol can do a retransmission and all fragments will arrive at the new server. + The only way of fully supporting fragmentation would be to synchronise fragments between all anycast servers. This is considered to be too much overhead, so there are two non-perfect solutions for these problems. Either fragmentation HAS TO be disabled or if not all fragments arrive at the same server the IP datagramm HAS TO be discarded. As routing changes are not expected to occur very frequently, the encapsulated protocol can do a retransmission and all fragments will arrive at the new server. </p> -<p>If the payload type is IP and the ip headers's Don't Fragment (DF) bit is set, than the DF bit of the outer IP header HAS TO be set as well. +<p>If the payload type is IP and the IP headers' Don't Fragment (DF) bit is set, then the DF bit of the outer IP header HAS TO be set as well. </p> <a name="anchor11"></a><br /><hr /> <table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table> @@ -464,32 +464,32 @@ Header format</h3> <a name="rfc.section.4.2"></a><h3>4.2. sequence number</h3> -<p>The sequence number is a 32 bit unsigned integer in network byte order. It starts with a random value and is increased by 1 for every sent packet. After the maximum value, it starts over from 0. This overrun causes the ROC to be increased. +<p>The sequence number is a 32 bit unsigned integer in network byte order. It starts with a random value and is increased by 1 for every sent packet. After the maximum value it starts over from 0. This overrun causes the ROC to be increased. </p> <a name="anchor15"></a><br /><hr /> <table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table> <a name="rfc.section.4.3"></a><h3>4.3. sender ID</h3> -<p>The sender ID is a 16 bit unsigned integer. It HAS TO be unique for every sender sharing the same anycast address +<p>The sender ID is a 16 bit unsigned integer. It HAS TO be unique for every sender sharing the same anycast address. </p> <a name="anchor16"></a><br /><hr /> <table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table> <a name="rfc.section.4.4"></a><h3>4.4. MUX</h3> -<p>The MUX (multiplex) field is a 16 bit unsigned integer. It is used to destinguish multible tunnel connections. +<p>The MUX (multiplex) field is a 16 bit unsigned integer. It is used to distinguish multiple tunnel connections. </p> <a name="anchor17"></a><br /><hr /> <table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table> <a name="rfc.section.4.5"></a><h3>4.5. -payload type field</h3> +payload type</h3> <p>The payload type field defines the payload protocol. ETHER TYPE protocol numbers are used. <a href='http://www.iana.org/assignments/ethernet-numbers'>See IANA assigned ethernet numbers</a> . The values 0000-05DC are reserverd and MUST NOT be used. <br /><hr class="insert" /> <a name="prot_type_table"></a> -<p>Some examples for protocol types +<p>Some examples for protocol numbers </p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre> HEX 0000 Reserved @@ -507,7 +507,7 @@ HEX <a name="rfc.section.4.6"></a><h3>4.6. payload</h3> -<p>A packet of the type payload type (e.g. an IP packet). +<p>A packet of type payload type (e.g. an IP packet). </p> <a name="anchor19"></a><br /><hr /> <table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table> @@ -516,28 +516,28 @@ padding (OPTIONAL)</h3> <p>Padding of max 255 octets. None of the pre-defined encryption transforms uses any padding; for - these, the plaintext and encrypted payload sizes match exactly. Transforms are based on transforms of the SRTP protocol and these transforms might use the RTP padding format, so a RTP like padding is supported. If the padding count field is present, than the padding count field MUST be set to the padding length. + these, the plaintext and encrypted payload sizes match exactly. Transforms are based on transforms of the SRTP protocol and therefore might use the RTP padding format, so a RTP-like padding is supported. If the padding count field is present, the padding count field MUST be set to the padding length. </p> <a name="anchor20"></a><br /><hr /> <table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table> <a name="rfc.section.4.8"></a><h3>4.8. padding count (OPTIONAL)</h3> -<p>The number of octets of the padding field. This field is optional. It's presence is signaled by the key management and not by this protocol. If this field isn't present, the padding field MUST NOT be present as well. +<p>The number of octets of the padding field. This field is optional. Its presence is signaled by the key management and not by this protocol. If this field isn't present, the padding field MUST NOT be present as well. </p> <a name="anchor21"></a><br /><hr /> <table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table> <a name="rfc.section.4.9"></a><h3>4.9. MKI (OPTIONAL)</h3> -<p>The MKI (Master Key Identifier) is OPTIONAL and of configurable length. See <a class='info' href='#RFC3711'>SRTP Section 3.1<span> (</span><span class='info'>Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, “The Secure Real-time Transport Protocol (SRTP),” March 2004.</span><span>)</span></a> [1] for details +<p>The MKI (Master Key Identifier) is OPTIONAL and of configurable length. See <a class='info' href='#RFC3711'>SRTP Section 3.1<span> (</span><span class='info'>Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, “The Secure Real-time Transport Protocol (SRTP),” March 2004.</span><span>)</span></a> [1] for details. </p> <a name="anchor22"></a><br /><hr /> <table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table> <a name="rfc.section.4.10"></a><h3>4.10. authentication tag (RECOMMENDED)</h3> -<p>The authentication tag is RECOMMENDED and of configurable length. It contains a cryptographic checksum of the sender ID, sequence number and the encrypted portion, but not of the MKI. On sender side encryption HAS TO be done before calculating the authentication tag. A receiver HAS TO calculate the authentication tag before decrypting the encrypted portion. +<p>The authentication tag is RECOMMENDED and of configurable length. It contains a cryptographic checksum of the sender ID, sequence number and the encrypted portion, but not of the MKI. On transmitter side encryption HAS TO be done before calculating the authentication tag. A receiver HAS TO calculate the authentication tag before decrypting the encrypted portion. </p> <a name="anchor23"></a><br /><hr /> <table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table> @@ -546,7 +546,7 @@ Encryption</h3> <p>Encryption is done in the same way as for <a class='info' href='#RFC3711'>SRTP<span> (</span><span class='info'>Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, “The Secure Real-time Transport Protocol (SRTP),” March 2004.</span><span>)</span></a> [1]. This section will only discuss some small changes that HAVE TO be made. Please read <a class='info' href='#RFC3711'>SRTP RFC3711 section 3-9<span> (</span><span class='info'>Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, “The Secure Real-time Transport Protocol (SRTP),” March 2004.</span><span>)</span></a> [1] for details. </p> -<p>The least significant bits of SSRC are replaced by the sender ID and the most significant bits are replaced by the mux. For the SRTP SEQ the 16 least significant bits of the SATP sequence number are used and the 16 most significant bits of the sequence number replace the 16 least significant bits of the SRTP ROC. +<p>The least significant bits of SSRC are replaced by the sender ID and the most significant bits are replaced by the MUX. For the SRTP SEQ the 16 least significant bits of the SATP sequence number are used and the 16 most significant bits of the sequence number replace the 16 least significant bits of the SRTP ROC. </p><br /><hr class="insert" /> <a name="srtp_vs_satp"></a> @@ -586,7 +586,7 @@ Security Considerations</h3> <a name="rfc.section.5.1"></a><h3>5.1. Replay protection</h3> -<p>Replay protection is done by a replay list. Every anycast receiver has it's own replay list, which SHOULDN'T be syncronised, because of massive overhead. This leads to an additional possible attack. A attacker is able to replay a captured packet once to every anycast receiver. This attack is considered of be very unlikely, because multiple attack hosts in different loactions are needed to reach the seperate anycast receivers and the number of replays is limited to the count of receivers - 1. Such replays might also happen because of routing problems, so a payload protocol HAS TO be robust against a small number of duplicated packages. The window size and position HAS TO be syncronised between multible anycast receivers to limit this attack. +<p>Replay protection is done by a replay list. Every anycast receiver has its own replay list, which SHOULDN'T be syncronised because of massive overhead. This leads to an additional possible attack. An attacker is able to replay a captured packet once to every anycast receiver. This attack is considered be very unlikely because multiple attack hosts in different locations are needed to reach seperate anycast receivers and the number of replays is limited to count of receivers - 1. Such replays might also happen because of routing problems, so a payload protocol HAS TO be robust against a small number of duplicated packages. The window size and position HAS TO be syncronised between multiple anycast receivers to limit this attack. </p> <a name="anchor26"></a><br /><hr /> <table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table> |