draft-ietf-tls-cached-info-08.txt		draft-ietf-tls-cached-info-09.txt
	INTERNET-DRAFT S. Santesson (3xA Security)		INTERNET-DRAFT S. Santesson (3xA Security)
	Intended Status: Proposed Standard		Intended Status: Proposed Standard
	Expires: October 22, 2010 April 20, 2010		Expires: January 13, 2011 July 12, 2010
	Transport Layer Security (TLS) Cached Information Extension		Transport Layer Security (TLS) Cached Information Extension
	<draft-ietf-tls-cached-info-08.txt>		<draft-ietf-tls-cached-info-09.txt>
	Abstract		Abstract
	This document defines a Transport Layer Security (TLS) extension for		This document defines a Transport Layer Security (TLS) extension for
	cached information. This extension allows the TLS client to inform a		cached information. This extension allows the TLS client to inform a
	server of cached information from previous TLS sessions, allowing the		server of cached information from previous TLS handshakes, allowing
	server to omit sending cached static information to the client during		the server to omit sending cached static information to the client
	the TLS handshake protocol exchange.		during the TLS handshake protocol exchange.
	Status of this Memo		Status of this Memo
	This Internet-Draft is submitted to IETF in full conformance with the		This Internet-Draft is submitted to IETF in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF), its areas, and its working groups. Note that		Task Force (IETF), its areas, and its working groups. Note that
	other groups may also distribute working documents as		other groups may also distribute working documents as
	Internet-Drafts.		Internet-Drafts.
	skipping to change at page 2, line 26		skipping to change at page 2, line 26
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
	1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3		1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Cached Information Extension . . . . . . . . . . . . . . . . . 4		2. Cached Information Extension . . . . . . . . . . . . . . . . . 4
	3. Extension Exchange . . . . . . . . . . . . . . . . . . . . . . 5		3. Extension Exchange . . . . . . . . . . . . . . . . . . . . . . 5
	3.1. Reconnaissance . . . . . . . . . . . . . . . . . . . . . . 5		3.1. Cached Information . . . . . . . . . . . . . . . . . . . . 5
	3.2. Cached Information . . . . . . . . . . . . . . . . . . . . 5		3.2. Reconnaissance . . . . . . . . . . . . . . . . . . . . . . 5
	4. Data Substitution . . . . . . . . . . . . . . . . . . . . . . . 6		4. Cached Information Substitution . . . . . . . . . . . . . . . . 6
	4.1. Data Substitution Syntax for certificate_chain . . . . . . 6		4.1. Substitution Syntax for certificate_chain . . . . . . . . 6
	4.2. Data Substitution Syntax for trusted_cas . . . . . . . . . 7		4.2. Substitution Syntax for trusted_cas . . . . . . . . . . . 6
	5. Security Considerations . . . . . . . . . . . . . . . . . . . . 8		5. Security Considerations . . . . . . . . . . . . . . . . . . . . 8
	6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8		6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8
	7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8		7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8
	8. Normative References . . . . . . . . . . . . . . . . . . . . . 9		8. Normative References . . . . . . . . . . . . . . . . . . . . . 9
	Annex A - 64 bit FNV-1a digest . . . . . . . . . . . . . . . . . 10		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
	A.1. Definition (Normative) . . . . . . . . . . . . . . . . . 10
	A.2 Java code sample (Informative) . . . . . . . . . . . . . 11
	A.3. C code sample (Informative) . . . . . . . . . . . . . . . 12
	A.4. Digest samples (Informative) . . . . . . . . . . . . . . 13
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
	1. Introduction		1. Introduction
	TLS handshakes often include fairly static information such as server		TLS handshakes often include fairly static information such as server
	certificate and a list of trusted Certification Authorities (CAs).		certificate and a list of trusted Certification Authorities (CAs).
	Static information such as a server certificate can be of		Static information such as a server certificate can be of
	considerable size. This is the case in particular if the server		considerable size. This is the case in particular if the server
	certificate is bundled with a complete certificate path, including		certificate is bundled with a complete certificate path, including
	all intermediary certificates up to the trust anchor public key.		all intermediary certificates up to the trust anchor public key.
	Significant benefits can be achieved in low bandwidth and high		Significant benefits can be achieved in low bandwidth and high
	latency networks, in particular if the communication channel also has		latency networks, in particular if the communication channel also has
	a relatively high rate of transmission errors, if a known and		a relatively high rate of transmission errors, if a known and
	previously cached server certificate path can be omitted from the TLS		previously cached server certificate path can be omitted from the TLS
	handshake.		handshake.
	This specification defines the Cached Information TLS extension,		This specification defines the Cached Information TLS extension,
	which may be used by a client and a server to exclude transmission of		which may be used by a client and a server to exclude transmission of
	known cached parameters from the TLS handshake.		cached information from the TLS handshake.
	1.1. Terminology		1.1. Terminology
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in RFC 2119 [RFC2119].		document are to be interpreted as described in RFC 2119 [RFC2119].
	2. Cached Information Extension		2. Cached Information Extension
	A new extension type (cached_information(TBD)) is defined and used in		A new extension type (cached_information(TBD)) is defined and used in
	both the client hello and server hello messages. The extension type		both the client hello and server hello messages. The extension type
	is specified as follows.		is specified as follows.
	enum {		enum {
	cached_information(TBD), (65535)		cached_information(TBD), (65535)
	} ExtensionType;		} ExtensionType;
	The "extension_data" field of this extension, when included in the		The extension_data field of this extension, when included in the
	client hello, SHALL contain "CachedInformation" according to the		client hello, SHALL contain CachedInformation according to the
	following structure:		following structure:
	enum {		enum {
	certificate_chain(1), trusted_cas(2), (255)		certificate_chain(1), trusted_cas(2), (255)
	} CachedInformationType;		} CachedInformationType;
	struct {		struct {
	CachedInformationType type;		CachedInformationType type;
	opaque digest_value<0..8>;		HashAlgorithm hash;
			opaque hash_value<1..255>;
	} CachedObject;		} CachedObject;
	struct {		struct {
	CachedObject cached_info<1..2048>;		CachedObject cached_info<1..2^16-1>;
	} CachedInformation;		} CachedInformation;
	The digest_value of a CachedObject MUST either be empty (0 bytes) or
	contain a 64 bit FNV digest (8 bytes) as specified in Annex A. The 64
	bit integer is represented as an 8 byte digest_value in big-endian
	order (with most significant bits in the first byte and least
	significant bits in the last byte).
	When CachedInformationType identifies certificate_chain, then		When CachedInformationType identifies certificate_chain, then
	digest_value MUST include a digest calculated over the		hash_value MUST include a hash calculated over the certificate_list
	certificate_list element of a server side Certificate message,		element of a server side Certificate message, excluding the three
	excluding the three length bytes of the certificate_list vector.		length bytes of the certificate_list vector.
	When CachedInformationType identifies trusted_cas, then digest_value		When CachedInformationType identifies trusted_cas, then hash_value
	MUST include a digest calculated over the certificate_authorities		MUST include a hash calculated over the certificate_authorities
	element of a server side CertificateRequest message, excluding the		element of a server side CertificateRequest message, excluding the
	two length bytes of the certificate_authorities vector.		two length bytes of the certificate_authorities vector.
			The hash algorithm used to calculate hash values SHALL be the hash
			algorithm that was used to generate the Finished message in the
			handshake exchange from which the hashed information was cached. Hash
			algorithm identifiers are defined in the RFC 5246 [RFC5246]
			HashAlgorithm registry.
	Other specifications MAY define more CachedInformationType types.		Other specifications MAY define more CachedInformationType types.
	3. Extension Exchange		3. Extension Exchange
	3.1. Reconnaissance		3.1. Cached Information
	A client MAY include an empty cached_information extension (with
	empty extension_data field) in its (extended) client hello to query
	whether the server supports cached information.
	A server indicates that it supports cached information in handshakes
	according to section 3.2. by including a cached_information extension
	in its (extended) server hello.
	3.2. Cached Information
	Clients MAY specify cached information from previous handshakes by		Clients MAY include a "cached_information" extension in the
	including a "cached_information" extension in the (extended) client		(extended) client hello, which MAY contain zero or more cached
	hello, which contains at least one cached object (CachedObject) for		objects (CachedObject).
	each present object type (CachedInformationType), as specified in
	section 2. Clients MAY need the ability to cache different values
	depending on other information in the Client Hello that modify what
	values the server uses, in particular the Server Name Indication
	[RFC4366] value. Clients sending a non-empty cached_information
	extension MUST provide a 64 bit (8 byte) digest_value for each cached
	object.
	Servers that receive an extended client hello containing a		Servers that receive an extended client hello containing a
	"cached_information" extension, MAY indicate that they support		"cached_information" extension MAY indicate that they support cached
	caching of information objects by including an cached_information		information objects by including a cached_information extension in
	extension in their (extended) server hello.		their (extended) server hello.
	A cached_information extension provided in the server hello has the		A cached_information extension provided in the server hello has the
	following semantics:		following semantics:
	o An empty cached_information extension indicates that the server		o An empty cached_information extension indicates that the server
	supports information caching but provides no information about		supports information caching but provides no information about
	what information types it supports.		what information types it supports.
	o A non-empty cached information extension indicates that the		o A non-empty cached information extension indicates that the
	server supports only those CachedInformationType types that are		server supports caching of each present CachedObject that matches
	identified by each present CachedObject.		the specified hash value. The server MAY support other cached
			objects that are not present in the extension.
	o A CachedObject with an empty digest_value indicates that the		Note: Clients may need the ability to cache different values
	server supports caching of the specified object type		depending on other information in the Client Hello that modify what
	(CachedInformationType), but does not specify any digest values		values the server uses, in particular the Server Name Indication
	it will accept.		[RFC4366] value.
	o A present non-empty digest_value indicates that the server will		3.2. Reconnaissance
	honor caching of objects of the specified type that matches the
	present digest value.
	4. Data Substitution		A client MAY include an empty cached_information extension (with
			empty extension_data field) in its (extended) client hello to query
			whether the server supports cached information.
			Upon receiving an empty cached_information extension, a server MAY
			indicate that it supports cached information in handshakes by
			including a cached_information extension in its (extended) server
			hello according to any of the available options in section 3.1.
			4. Cached Information Substitution
	Following a successful exchange of "cached_information" extensions,		Following a successful exchange of "cached_information" extensions,
	the server may substitute data objects in the handshake exchange with		the server MAY substitute cached information in the handshake
	a matching digest_value representing a matching object type. received		exchange with a matching CachedObject from the client hello
	from the client in its client hello.		"cached_information" extension.
	The handshake protocol will proceed using the cached data as if it		A substitution syntax that defines how the CachedObject structure is
	was provided in the handshake protocol. The Finished message will		carried in the handshake message MUST be defined for each
	however be calculated over the actual data exchanged in the handshake		CachedInformationType in a way that does not violate the syntax of
	protocol. That is, the Finished message will be calculated over the		the handshake message. The substitution syntax for
	digest values of cached information objects and not over the cached		certificate_chain(1) and trusted_cas(2) is provided below.
	objects that were omitted from transmission.
	Each CachedInformationType MUST specify how actual data is replaced		The handshake protocol SHALL proceed using the cached information as
	by a digest in a way that does not violate the defined syntax of		if it was provided in the handshake protocol. The Finished message
	existing handshake messages. the data exchange syntax for		SHALL be calculated over the actual data exchanged in the handshake
	certificate_chain(1) and trusted_cas(2) are provided below.		protocol. That is, the Finished message will be calculated over the
			hash values of cached information objects and not over the cached
			information that were omitted from transmission.
	The server MUST NOT provide more than one digest value as		The server MUST NOT include more than one CachedObject as
	substitution for the cached data.		substitution for the cached information.
	4.1. Data Substitution Syntax for certificate_chain		4.1. Substitution Syntax for certificate_chain
	When a digest for an object of type certificate_chain is provided in		When an object of type certificate_chain is provided in the client
	the client hello, the server MAY substitute the cached data with a		hello, the server MAY substitute the cached information with a
	matching digest value received from the client by expanding the		matching hash value received from the client by expanding the
	Certificate handshake message as follows.		Certificate handshake message as follows.
	Original handshake message syntax defined in RFC 5246 [RFC5246]:		Original handshake message syntax defined in RFC 5246 [RFC5246]:
	opaque ASN.1Cert<1..2^24-1>;		opaque ASN.1Cert<1..2^24-1>;
	struct {		struct {
	ASN.1Cert certificate_list<0..2^24-1>;		ASN.1Cert certificate_list<0..2^24-1>;
	} Certificate;		} Certificate;
	Substitution syntax is defined by expanding the definition of the		Substitution syntax is defined by expanding the syntax of the opaque
	opaque ASN.1Cert structure:		ASN.1Cert structure:
	DigestInfo ASN.1Cert<1..2^24-1>;
	struct {		CachedObject ASN.1Cert<1..2^24-1>;
	opaque digest_value<0..8>;
	} DigestInfo;
	4.2. Data Substitution Syntax for trusted_cas		4.2. Substitution Syntax for trusted_cas
	When a digest for an object of type trusted_cas is provided in the		When a hash for an object of type trusted_cas is provided in the
	client hello, the server MAY substitute the cached data with a		client hello, the server MAY substitute the cached information with a
	matching digest value received from the client by expanding the		matching hash value received from the client by expanding the
	CertificateRequest handshake message as follows.		CertificateRequest handshake message as follows.
	Original handshake message syntax defined in RFC 5246 [RFC5246]:		Original handshake message syntax defined in RFC 5246 [RFC5246]:
	opaque DistinguishedName<1..2^16-1>;		opaque DistinguishedName<1..2^16-1>;
	struct {		struct {
	ClientCertificateType certificate_types<1..2^8-1>;		ClientCertificateType certificate_types<1..2^8-1>;
	SignatureAndHashAlgorithm		SignatureAndHashAlgorithm
	supported_signature_algorithms<2^16-1>;		supported_signature_algorithms<2^16-1>;
	DistinguishedName certificate_authorities<0..2^16-1>;		DistinguishedName certificate_authorities<0..2^16-1>;
	} CertificateRequest		} CertificateRequest
	The substitution syntax is defined by expanding the definition of the		The substitution syntax is defined by expanding the syntax of the
	opaque DistinguishedName structure:		opaque DistinguishedName structure:
	DigestInfo DistinguishedName<1..2^16-1>;		CachedObject DistinguishedName<1..2^16-1>;
	struct {
	opaque digest_value<0..8>;
	} DigestInfo;
	5. Security Considerations		5. Security Considerations
	The digest algorithm used in this specification is required to have		The hash algorithm used in this specification is required to have
	reasonable random properties in order to provide reasonably unique		reasonable random properties in order to provide reasonably unique
	identifiers. There is no requirement that this digest algorithm must		identifiers. There is no clearly identified requirement that this
	have strong collision resistance. A non unique digest may at most		hash algorithm must have strong collision resistance. However since
	lead to a failed TLS handshake followed by a new attempt without the		the hash algorithm is used to represent data in the finished
	cached information extension. There are no identified security		calculation, the security properties of the finished calculation will
	threats that require the selected digest algorithm to have strong		change if a weaker hash algorithm is used to represent cached
	collision resistance.		information compared with the hash algorithm used to calculate the
			finished message.
			Caching information in an encrypted handshake (such as a renegotiated
			handshake) and sending a hash of that cached information in an
			unencrypted handshake might introduce integrity or data disclosure
			issues as it enables an attacker to identify if a known object (such
			as a known server certificate) has been used in previous encrypted
			handshakes. Information object types defined in this specification,
			such as server certificates, are public objects and usually not
			sensitive in this regard, but implementers should be aware if any
			cached information are subject to such security concerns and in such
			case SHOULD NOT send a hash over encrypted data in en unencrypted
			handshake.
	6. IANA Considerations		6. IANA Considerations
	1) Create an entry, cached_information(TBD), in the existing registry		1) Create an entry, cached_information(TBD), in the existing registry
	for ExtensionType (defined in RFC 5246 [RFC5246]).		for ExtensionType (defined in RFC 5246 [RFC5246]).
	2) Establish a registry for TLS CachedInformationType values. The		2) Establish a registry for TLS CachedInformationType values. The
	first entries in the registry are certificate_chain(1) and		first entries in the registry are certificate_chain(1) and
	trusted_cas(2). TLS CachedInformationType values in the inclusive		trusted_cas(2). TLS CachedInformationType values in the inclusive
	range 0-63 (decimal) are assigned via RFC 5226 [RFC5226] Standards		range 0-63 (decimal) are assigned via RFC 5226 [RFC5226] Standards
	Action. Values from the inclusive range 64-223 (decimal) are		Action. Values from the inclusive range 64-223 (decimal) are
	assigned via RFC 5226 Specification Required. Values from the		assigned via RFC 5226 Specification Required. Values from the
	inclusive range 224-255 (decimal) are reserved for RFC 5226		inclusive range 224-255 (decimal) are reserved for RFC 5226
	Private Use.		Private Use.
	7. Acknowledgements		7. Acknowledgements
	The author acknowledge input from many members of the TLS working		The author acknowledges input from many members of the TLS working
	group, Martin Rex for extensive review and input, Marsh Ray and Simon		group.
	Josefsson for coding and test vectors.
	8. Normative References		8. Normative References
	[RFC2119] S. Bradner, "Key words for use in RFCs to Indicate		[RFC2119] S. Bradner, "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119, March 1997		Requirement Levels", BCP 14, RFC 2119, March 1997
	[RFC5226] T. Narten, H. Alvestrand, "Guidelines for Writing an IANA		[RFC5226] T. Narten, H. Alvestrand, "Guidelines for Writing an IANA
	Considerations Section in RFCs", RFC 5226, May 2008		Considerations Section in RFCs", RFC 5226, May 2008
	[RFC5246] T. Dierks, E. Rescorla, "The Transport Layer Security		[RFC5246] T. Dierks, E. Rescorla, "The Transport Layer Security
	(TLS) Protocol Version 1.2", RFC 5246, August 2008		(TLS) Protocol Version 1.2", RFC 5246, August 2008
	[RFC4366] S. Blake-Wilson, M. Nystrom, D. Hopwood, J. Mikkelsen, T.		[RFC4366] S. Blake-Wilson, M. Nystrom, D. Hopwood, J. Mikkelsen, T.
	Wright, "Transport Layer Security (TLS) Extensions", RFC		Wright, "Transport Layer Security (TLS) Extensions", RFC
	4366, April 2006		4366, April 2006
	NOTE: RFC 4366 will be updated by RFC4366bis, currently in IESG		NOTE: RFC 4366 will be updated by RFC4366bis, currently in IESG
	process.		process.
	Annex A - 64 bit FNV-1a digest
	A.1. Definition (Normative)
	FNV-1 digest algorithm is a non-cryptographic hash function created
	by Glenn Fowler, Landon Curt Noll, and Phong Vo. The FNV digest
	algorithms and sample FNV source code have been released into the
	public domain. FNV-1 has two defined variants, FNV-1 and FNV-1a. The
	algorithm specified in this annex specifies the FNV-1a variant.
	The FNV-1a digest is generated as follows:
	digest = FNV_offset_basis
	for each octet_of_data to be digested {
	digest = digest XOR octet_of_data
	digest = digest * FNV_prime }
	return digest
	In the above pseudocode, all variables are unsigned integers. All
	variables, except for octet_of_data, have the same number of bits as
	the FNV digest (64 Bits). The variable, octet_of_data, is an 8 bit
	unsigned integer. Specifically for a 64 bit FNV-1a digest the
	following applies:
	o All variables, except for octet_of_data, are 64-bit unsigned
	integers.
	o The variable, octet_of_data, is an 8 bit unsigned integer.
	o The FNV_offset_basis is the 64-bit FNV offset basis value:
	14695981039346656037.
	o The FNV_prime is the 64-bit FNV prime value: 1099511628211.
	o The multiply function (indicated by the '*' symbol) returns the
	lower 64-bits of the product.
	o The XOR is an 8-bit operation that modifies only the lower 8-bits
	of the digest value.
	o The digest value returned is an 64-bit unsigned integer.
	A.2 Java code sample (Informative)
	/**
	* Java code sample, implementing 64 bit FNV-1a
	* By Stefan Santesson
	*/
	import java.math.BigInteger;
	public class FNV {
	static public BigInteger getFNV1a64Digest (String inpString) {
	BigInteger m = new BigInteger("2").pow(64);
	BigInteger fnvPrime = new BigInteger("1099511628211");
	BigInteger fnvOffsetBasis = new BigInteger
	("14695981039346656037");
	BigInteger digest = fnvOffsetBasis;
	for (int i = 0; i < inpString.length(); i++) {
	digest = digest.xor(BigInteger.valueOf(
	(int) inpString.charAt(i)));
	digest = digest.multiply(fnvPrime).mod(m);
	}
	return (digest);
	}
	}
	A.3. C code sample (Informative)
	fnv1a64.h:
	#ifndef FNV1A64_H
	#define FNV1A64_H
	#include <string.h> /* For size_t */
	#include <stdint.h> /* For uint64_t */
	extern uint64_t fnv1a64 (const uint8_t *buffer, size_t len);
	#endif
	fnv1a64.c:
	/* fnv1a.c -- Implementation of the FNV-1A non-cryptographic
	* hash function.
	* By Simon Josefsson <simon@josefsson.org> on 2010-03-30.
	*/
	#include "fnv1a64.h"
	#define FNV1A64_OFFSET_BASIS 14695981039346656037ULL
	#define FNV1A64_PRIME 1099511628211ULL
	uint64_t
	fnv1a64 (const uint8_t *buffer, size_t len)
	{
	uint64_t hash;
	size_t i;
	hash = FNV1A64_OFFSET_BASIS;
	for (i = 0; i < len; i++)
	{
	hash = hash ^ buffer[i];
	hash = hash * FNV1A64_PRIME;
	}
	return hash;
	}
	A.4. Digest samples (Informative)
	Digest samples for 64 bit FNV-1a
	For input data:
	null ("")
	0 bytes
	Digest is: CB F2 9C E4 84 22 23 25
	For input data:
	hex: 61 ("a")
	1 byte
	Digest is: AF 63 DC 4C 86 01 EC 8C
	For input data:
	hex: FF 00 00 01
	4 bytes
	Digest is: 69 61 19 64 91 CC 68 2D
	For input data:
	hex: 68 74 74 70 3A 2F 2F 65 6E 2E 77 69 6B 69 70 65
	64 69 61 2E 6F 72 67 2F 77 69 6B 69 2F 46 6F 77
	6C 65 72 5F 4E 6F 6C 6C 5F 56 6F 5F 68 61 73 68
	("http://en.wikipedia.org/wiki/Fowler_Noll_Vo_hash")
	48 bytes
	Digest is: D9 B9 57 FB 7F E7 94 C5
	Authors' Addresses		Authors' Addresses
	Stefan Santesson		Stefan Santesson
	3xA Security AB		3xA Security AB
	Bjornstorp 744		Scheelev. 17
	247 98 Genarp		223 70 Sweden
	Sweden
	EMail: sts@aaa-sec.com		EMail: sts@aaa-sec.com
End of changes. 37 change blocks.
	261 lines changed or deleted		106 lines changed or added
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