encode_keychange - produce the KeyChange string for SNMPv3 |
encode_keychange -t md5|sha1 [OPTIONS] |
encode_keychange produces a KeyChange string using the old and new passphrases as described in Section 5 of RFC 2274 "User-based Security Model (USM) for version 3 of the Simple Network Management Protocol (SNMPv3)". -t option is mandatory and specifies the hash transform type to use. The transform is used to convert passphrase to master key for a given user (Ku), convert master key to the localized key (Kul), and to hash the old Kul with the random bits. Passphrases are obtained by examining a number of sources until success (in order listed): |
command line options (see -N and -O options below); the file $HOME/.snmp/passphrase.ek which should only contain two lines with old and new passphrase; standard input −or− user input from the terminal. |
−E [0x]<engineID> EngineID used for Kul generation. |
<engineID> is intepreted as a hex string when preceeded by 0x, otherwise it is treated as a text string. If no <engineID> is specified, it is constructed from the first IP address for the local host. |
−f |
Force passphrases to be read from standard input. |
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−h |
Display the help message. |
−N "<new_passphrase>" |
Passphrase used to generate the new Ku. |
−O "<old_passphrase>" |
Passphrase used to generate the old Ku. |
−P |
Turn off the prompt for passphrases when getting data from standard input. |
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−v |
Be verbose. |
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−V |
Echo passphrases to terminal. |
The localized key method is defined in RFC 2274, Sections 2.6 and A.2, and originally documented in |
U. Blumenthal, N. C. Hien, B. Wijnen, "Key Derivation for Network Management Applications", IEEE Network Magazine, April/May issue, 1997. |