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SNMP-USM-DH-OBJECTS-MIB DEFINITIONS ::= BEGIN
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MODULE-IDENTITY, OBJECT-TYPE,
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experimental, Integer32
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MODULE-COMPLIANCE, OBJECT-GROUP
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FROM SNMP-USER-BASED-SM-MIB
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FROM SNMP-FRAMEWORK-MIB;
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snmpUsmDHObjectsMIB MODULE-IDENTITY
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LAST-UPDATED "200003060000Z" -- 6 March 2000, Midnight
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ORGANIZATION "Excite@Home"
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CONTACT-INFO "Author: Mike StJohns
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Redwood City, CA 94063
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Email: stjohns@corp.home.net
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Phone: +1-650-556-5368"
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"The management information definitions for providing forward
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secrecy for key changes for the usmUserTable, and for providing a
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method for 'kickstarting' access to the agent via a Diffie-Helman
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REVISION "200003060000Z"
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"Initial version published as RFC 2786."
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::= { experimental 101 } -- IANA DHKEY-CHANGE 101
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usmDHKeyObjects OBJECT IDENTIFIER ::= { snmpUsmDHObjectsMIB 1 }
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usmDHKeyConformance OBJECT IDENTIFIER ::= { snmpUsmDHObjectsMIB 2 }
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DHKeyChange ::= TEXTUAL-CONVENTION
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"Upon initialization, or upon creation of a row containing an
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object of this type, and after any successful SET of this value, a
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GET of this value returns 'y' where y = g^xa MOD p, and where g is
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the base from usmDHParameters, p is the prime from
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usmDHParameters, and xa is a new random integer selected by the
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agent in the interval 2^(l-1) <= xa < 2^l < p-1. 'l' is the
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optional privateValueLength from usmDHParameters in bits. If 'l'
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is omitted, then xa (and xr below) is selected in the interval 0
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<= xa < p-1. y is expressed as an OCTET STRING 'PV' of length 'k'
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y = SUM 2^(8(k-i)) PV'i
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where PV1,...,PVk are the octets of PV from first to last, and
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A successful SET consists of the value 'y' expressed as an OCTET
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STRING as above concatenated with the value 'z'(expressed as an
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OCTET STRING in the same manner as y) where z = g^xr MOD p, where
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g, p and l are as above, and where xr is a new random integer
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selected by the manager in the interval 2^(l-1) <= xr < 2^l <
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p-1. A SET to an object of this type will fail with the error
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wrongValue if the current 'y' does not match the 'y' portion of
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the value of the varbind for the object. (E.g. GET yout, SET
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concat(yin, z), yout <> yin).
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Note that the private values xa and xr are never transmitted from
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manager to device or vice versa, only the values y and z.
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Obviously, these values must be retained until a successful SET on
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the associated object.
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The shared secret 'sk' is calculated at the agent as sk = z^xa MOD
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p, and at the manager as sk = y^xr MOD p.
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Each object definition of this type MUST describe how to map from
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the shared secret 'sk' to the operational key value used by the
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protocols and operations related to the object. In general, if n
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bits of key are required, the author suggests using the n
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right-most bits of the shared secret as the operational key value."
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"-- Diffie-Hellman Key-Agreement Standard, PKCS #3;
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RSA Laboratories, November 1993"
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usmDHPublicObjects OBJECT IDENTIFIER ::= { usmDHKeyObjects 1 }
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usmDHParameters OBJECT-TYPE
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"The public Diffie-Hellman parameters for doing a Diffie-Hellman
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key agreement for this device. This is encoded as an ASN.1
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DHParameter per PKCS #3, section 9. E.g.
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DHParameter ::= SEQUENCE {
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privateValueLength INTEGER OPTIONAL }
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Implementors are encouraged to use either the values from
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Oakley Group 1 or the values of from Oakley Group 2 as specified
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in RFC-2409, The Internet Key Exchange, Section 6.1, 6.2 as the
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default for this object. Other values may be used, but the
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security properties of those values MUST be well understood and
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MUST meet the requirements of PKCS #3 for the selection of
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Diffie-Hellman primes.
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In addition, any time usmDHParameters changes, all values of
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type DHKeyChange will change and new random numbers MUST be
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generated by the agent for each DHKeyChange object."
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"-- Diffie-Hellman Key-Agreement Standard, PKCS #3,
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RSA Laboratories, November 1993
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-- The Internet Key Exchange, RFC 2409, November 1998,
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::= { usmDHPublicObjects 1 }
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usmDHUserKeyTable OBJECT-TYPE
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SYNTAX SEQUENCE OF UsmDHUserKeyEntry
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MAX-ACCESS not-accessible
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"This table augments and extends the usmUserTable and provides
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4 objects which exactly mirror the objects in that table with the
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textual convention of 'KeyChange'. This extension allows key
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changes to be done in a manner where the knowledge of the current
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secret plus knowledge of the key change data exchanges (e.g. via
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wiretapping) will not reveal the new key."
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::= { usmDHPublicObjects 2 }
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usmDHUserKeyEntry OBJECT-TYPE
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SYNTAX UsmDHUserKeyEntry
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MAX-ACCESS not-accessible
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"A row of DHKeyChange objects which augment or replace the
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functionality of the KeyChange objects in the base table row."
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AUGMENTS { usmUserEntry }
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::= {usmDHUserKeyTable 1 }
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UsmDHUserKeyEntry ::= SEQUENCE {
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usmDHUserAuthKeyChange DHKeyChange,
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usmDHUserOwnAuthKeyChange DHKeyChange,
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usmDHUserPrivKeyChange DHKeyChange,
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usmDHUserOwnPrivKeyChange DHKeyChange
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usmDHUserAuthKeyChange OBJECT-TYPE
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MAX-ACCESS read-create
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"The object used to change any given user's Authentication Key
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using a Diffie-Hellman key exchange.
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The right-most n bits of the shared secret 'sk', where 'n' is the
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number of bits required for the protocol defined by
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usmUserAuthProtocol, are installed as the operational
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authentication key for this row after a successful SET."
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::= { usmDHUserKeyEntry 1 }
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usmDHUserOwnAuthKeyChange OBJECT-TYPE
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MAX-ACCESS read-create
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"The object used to change the agents own Authentication Key
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using a Diffie-Hellman key exchange.
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The right-most n bits of the shared secret 'sk', where 'n' is the
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number of bits required for the protocol defined by
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usmUserAuthProtocol, are installed as the operational
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authentication key for this row after a successful SET."
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::= { usmDHUserKeyEntry 2 }
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usmDHUserPrivKeyChange OBJECT-TYPE
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MAX-ACCESS read-create
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"The object used to change any given user's Privacy Key using
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a Diffie-Hellman key exchange.
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The right-most n bits of the shared secret 'sk', where 'n' is the
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number of bits required for the protocol defined by
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usmUserPrivProtocol, are installed as the operational privacy key
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for this row after a successful SET."
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::= { usmDHUserKeyEntry 3 }
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usmDHUserOwnPrivKeyChange OBJECT-TYPE
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MAX-ACCESS read-create
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"The object used to change the agent's own Privacy Key using a
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Diffie-Hellman key exchange.
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The right-most n bits of the shared secret 'sk', where 'n' is the
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number of bits required for the protocol defined by
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usmUserPrivProtocol, are installed as the operational privacy key
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for this row after a successful SET."
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::= { usmDHUserKeyEntry 4 }
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usmDHKickstartGroup OBJECT IDENTIFIER ::= { usmDHKeyObjects 2 }
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usmDHKickstartTable OBJECT-TYPE
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SYNTAX SEQUENCE OF UsmDHKickstartEntry
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MAX-ACCESS not-accessible
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"A table of mappings between zero or more Diffie-Helman key
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agreement values and entries in the usmUserTable. Entries in this
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table are created by providing the associated device with a
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Diffie-Helman public value and a usmUserName/usmUserSecurityName
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pair during initialization. How these values are provided is
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outside the scope of this MIB, but could be provided manually, or
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through a configuration file. Valid public value/name pairs
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result in the creation of a row in this table as well as the
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creation of an associated row (with keys derived as indicated) in
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the usmUserTable. The actual access the related usmSecurityName
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has is dependent on the entries in the VACM tables. In general,
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an implementor will specify one or more standard security names
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and will provide entries in the VACM tables granting various
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levels of access to those names. The actual content of the VACM
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table is beyond the scope of this MIB.
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Note: This table is expected to be readable without authentication
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using the usmUserSecurityName 'dhKickstart'. See the conformance
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statements for details."
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::= { usmDHKickstartGroup 1 }
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usmDHKickstartEntry OBJECT-TYPE
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SYNTAX UsmDHKickstartEntry
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MAX-ACCESS not-accessible
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"An entry in the usmDHKickstartTable. The agent SHOULD either
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delete this entry or mark it as inactive upon a successful SET of
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any of the KeyChange-typed objects in the usmUserEntry or upon a
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successful SET of any of the DHKeyChange-typed objects in the
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usmDhKeyChangeEntry where the related usmSecurityName (e.g. row of
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usmUserTable or row of ushDhKeyChangeTable) equals this entry's
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usmDhKickstartSecurityName. In otherwords, once you've changed
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one or more of the keys for a row in usmUserTable with a
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particular security name, the row in this table with that same
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security name is no longer useful or meaningful."
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INDEX { usmDHKickstartIndex }
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::= {usmDHKickstartTable 1 }
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UsmDHKickstartEntry ::= SEQUENCE {
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usmDHKickstartIndex Integer32,
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usmDHKickstartMyPublic OCTET STRING,
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usmDHKickstartMgrPublic OCTET STRING,
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usmDHKickstartSecurityName SnmpAdminString
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usmDHKickstartIndex OBJECT-TYPE
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SYNTAX Integer32 (1..2147483647)
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MAX-ACCESS not-accessible
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"Index value for this row."
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::= { usmDHKickstartEntry 1 }
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usmDHKickstartMyPublic OBJECT-TYPE
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"The agent's Diffie-Hellman public value for this row. At
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initialization, the agent generates a random number and derives
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its public value from that number. This public value is published
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here. This public value 'y' equals g^r MOD p where g is the from
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the set of Diffie-Hellman parameters, p is the prime from those
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parameters, and r is a random integer selected by the agent in the
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interval 2^(l-1) <= r < p-1 < 2^l. If l is unspecified, then r is
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a random integer selected in the interval 0 <= r < p-1
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The public value is expressed as an OCTET STRING 'PV' of length
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y = SUM 2^(8(k-i)) PV'i
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where PV1,...,PVk are the octets of PV from first to last, and
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The following DH parameters (Oakley group #2, RFC 2409, sec 6.1,
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6.2) are used for this object:
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p = FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1
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29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD
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EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245
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E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED
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EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE65381
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"-- Diffie-Hellman Key-Agreement Standard, PKCS#3v1.4;
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RSA Laboratories, November 1993
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-- The Internet Key Exchange, RFC2409;
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Harkins, D., Carrel, D.; November 1998"
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::= { usmDHKickstartEntry 2 }
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usmDHKickstartMgrPublic OBJECT-TYPE
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"The manager's Diffie-Hellman public value for this row. Note
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that this value is not set via the SNMP agent, but may be set via
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some out of band method, such as the device's configuration file.
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The manager calculates this value in the same manner and using the
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same parameter set as the agent does. E.g. it selects a random
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number 'r', calculates y = g^r mod p and provides 'y' as the
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public number expressed as an OCTET STRING. See
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usmDHKickstartMyPublic for details.
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When this object is set with a valid value during initialization,
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a row is created in the usmUserTable with the following values:
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usmUserEngineID localEngineID
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usmUserName [value of usmDHKickstartSecurityName]
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usmUserSecurityName [value of usmDHKickstartSecurityName]
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usmUserCloneFrom ZeroDotZero
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usmUserAuthProtocol usmHMACMD5AuthProtocol
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usmUserAuthKeyChange -- derived from set value
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usmUserOwnAuthKeyChange -- derived from set value
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usmUserPrivProtocol usmDESPrivProtocol
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usmUserPrivKeyChange -- derived from set value
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usmUserOwnPrivKeyChange -- derived from set value
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usmUserStorageType permanent
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A shared secret 'sk' is calculated at the agent as sk =
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mgrPublic^r mod p where r is the agents random number and p is the
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DH prime from the common parameters. The underlying privacy key
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for this row is derived from sk by applying the key derivation
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function PBKDF2 defined in PKCS#5v2.0 with a salt of 0xd1310ba6,
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and iterationCount of 500, a keyLength of 16 (for
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usmDESPrivProtocol), and a prf (pseudo random function) of
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'id-hmacWithSHA1'. The underlying authentication key for this row
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is derived from sk by applying the key derivation function PBKDF2
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with a salt of 0x98dfb5ac , an interation count of 500, a
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keyLength of 16 (for usmHMAC5AuthProtocol), and a prf of
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'id-hmacWithSHA1'. Note: The salts are the first two words in the
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ks0 [key schedule 0] of the BLOWFISH cipher from 'Applied
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Cryptography' by Bruce Schnier - they could be any relatively
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random string of bits.
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The manager can use its knowledge of its own random number and the
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agent's public value to kickstart its access to the agent in a
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secure manner. Note that the security of this approach is
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directly related to the strength of the authorization security of
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the out of band provisioning of the managers public value
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(e.g. the configuration file), but is not dependent at all on the
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strength of the confidentiality of the out of band provisioning
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"-- Password-Based Cryptography Standard, PKCS#5v2.0;
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RSA Laboratories, March 1999
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-- Applied Cryptography, 2nd Ed.; B. Schneier,
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Counterpane Systems; John Wiley & Sons, 1996"
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::= { usmDHKickstartEntry 3 }
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usmDHKickstartSecurityName OBJECT-TYPE
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SYNTAX SnmpAdminString
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"The usmUserName and usmUserSecurityName in the usmUserTable
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associated with this row. This is provided in the same manner and
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at the same time as the usmDHKickstartMgrPublic value -
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e.g. possibly manually, or via the device's configuration file."
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::= { usmDHKickstartEntry 4 }
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usmDHKeyMIBCompliances OBJECT IDENTIFIER ::= { usmDHKeyConformance 1 }
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usmDHKeyMIBGroups OBJECT IDENTIFIER ::= { usmDHKeyConformance 2 }
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usmDHKeyMIBCompliance MODULE-COMPLIANCE
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"The compliance statement for this module."
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GROUP usmDHKeyMIBBasicGroup
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"This group MAY be implemented by any agent which
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implements the usmUserTable and which wishes to provide the
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ability to change user and agent authentication and privacy
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keys via Diffie-Hellman key exchanges."
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GROUP usmDHKeyParamGroup
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"This group MUST be implemented by any agent which
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implements a MIB containing the DHKeyChange Textual
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Convention defined in this module."
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GROUP usmDHKeyKickstartGroup
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"This group MAY be implemented by any agent which
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implements the usmUserTable and which wishes the ability to
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populate the USM table based on out-of-band provided DH
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Any agent implementing this group is expected to provide
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preinstalled entries in the vacm tables as follows:
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In the usmUserTable: This entry allows access to the
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system and dhKickstart groups
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usmUserEngineID localEngineID
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usmUserName 'dhKickstart'
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usmUserSecurityName 'dhKickstart'
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usmUserCloneFrom ZeroDotZero
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usmUserAuthProtocol none
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usmUserAuthKeyChange ''
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usmUserOwnAuthKeyChange ''
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usmUserPrivProtocol none
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usmUserPrivKeyChange ''
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usmUserOwnPrivKeyChange ''
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usmUserStorageType permanent
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In the vacmSecurityToGroupTable: This maps the initial
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user into the accessible objects.
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vacmSecurityModel 3 (USM)
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vacmSecurityName 'dhKickstart'
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vacmGroupName 'dhKickstart'
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vacmSecurityToGroupStorageType permanent
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vacmSecurityToGroupStatus active
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In the vacmAccessTable: Group name to view name translation.
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vacmGroupName 'dhKickstart'
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vacmAccessContextPrefix ''
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vacmAccessSecurityModel 3 (USM)
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vacmAccessSecurityLevel noAuthNoPriv
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vacmAccessContextMatch exact
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vacmAccessReadViewName 'dhKickRestricted'
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vacmAccessWriteViewName ''
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vacmAccessNotifyViewName 'dhKickRestricted'
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vacmAccessStorageType permanent
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vacmAccessStatus active
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In the vacmViewTreeFamilyTable: Two entries to allow the
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initial entry to access the system and kickstart groups.
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vacmViewTreeFamilyViewName 'dhKickRestricted'
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vacmViewTreeFamilySubtree 1.3.6.1.2.1.1 (system)
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vacmViewTreeFamilyMask ''
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vacmViewTreeFamilyType 1
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vacmViewTreeFamilyStorageType permanent
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vacmViewTreeFamilyStatus active
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vacmViewTreeFamilyViewName 'dhKickRestricted'
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vacmViewTreeFamilySubtree (usmDHKickstartTable OID)
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vacmViewTreeFamilyMask ''
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vacmViewTreeFamilyType 1
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vacmViewTreeFamilyStorageType permanent
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vacmViewTreeFamilyStatus active
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OBJECT usmDHParameters
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"It is compliant to implement this object as read-only for
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::= { usmDHKeyMIBCompliances 1 }
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usmDHKeyMIBBasicGroup OBJECT-GROUP
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usmDHUserAuthKeyChange,
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usmDHUserOwnAuthKeyChange,
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usmDHUserPrivKeyChange,
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usmDHUserOwnPrivKeyChange
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::= { usmDHKeyMIBGroups 1 }
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usmDHKeyParamGroup OBJECT-GROUP
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"The mandatory object for all MIBs which use the DHKeyChange
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::= { usmDHKeyMIBGroups 2 }
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usmDHKeyKickstartGroup OBJECT-GROUP
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usmDHKickstartMyPublic,
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usmDHKickstartMgrPublic,
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usmDHKickstartSecurityName
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"The objects used for kickstarting one or more SNMPv3 USM
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associations via a configuration file or other out of band,
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non-confidential access."
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::= { usmDHKeyMIBGroups 3 }
added
removed
mibs/SNMP-USM-DH-OBJECTS-MIB.txt
