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10139N/A<
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th colspan="3" align="center"><
span class="application">isc-hmac-fixup</
span></
th></
tr>
10139N/A<
th width="60%" align="center">Manual pages</
th>
10139N/A<
div class="refentry" lang="en">
10139N/A<
p><
span class="application">isc-hmac-fixup</
span> — fixes HMAC keys generated by older versions of BIND</
p>
10139N/A<
div class="cmdsynopsis"><
p><
code class="command">isc-hmac-fixup</
code> {<
em class="replaceable"><
code>algorithm</
code></
em>} {<
em class="replaceable"><
code>secret</
code></
em>}</
p></
div>
10139N/A<
div class="refsect1" lang="en">
10139N/A<
a name="id2649363"></
a><
h2>DESCRIPTION</
h2>
10139N/A Versions of BIND 9 up to and including BIND 9.6 had a bug causing
10139N/A HMAC-SHA* TSIG keys which were longer than the digest length of the
10139N/A hash algorithm (
i.e., SHA1 keys longer than 160 bits, SHA256 keys
10139N/A longer than 256 bits, etc) to be used incorrectly, generating a
10139N/A message authentication code that was incompatible with other DNS
10139N/A This bug has been fixed in BIND 9.7. However, the fix may
10139N/A cause incompatibility between older and newer versions of
10139N/A BIND, when using long keys. <
span><
strong class="command">isc-hmac-fixup</
strong></
span>
10139N/A modifies those keys to restore compatibility.
10139N/A To modify a key, run <
span><
strong class="command">isc-hmac-fixup</
strong></
span> and
10139N/A specify the key's algorithm and secret on the command line. If the
10139N/A secret is longer than the digest length of the algorithm (64 bytes
10139N/A for SHA1 through SHA256, or 128 bytes for SHA384 and SHA512), then a
10139N/A new secret will be generated consisting of a hash digest of the old
10139N/A secret. (If the secret did not require conversion, then it will be
10139N/A<
div class="refsect1" lang="en">
10139N/A<
a name="id2649390"></
a><
h2>SECURITY CONSIDERATIONS</
h2>
10139N/A Secrets that have been converted by <
span><
strong class="command">isc-hmac-fixup</
strong></
span>
10139N/A are shortened, but as this is how the HMAC protocol works in
10139N/A operation anyway, it does not affect security. RFC 2104 notes,
10139N/A "Keys longer than [the digest length] are acceptable but the
10139N/A extra length would not significantly increase the function
15713N/A<
div class="refsect1" lang="en">
12773N/A<
a name="id2649406"></
a><
h2>SEE ALSO</
h2>
12773N/A <
em class="citetitle">BIND 9 Administrator Reference Manual</
em>,
12773N/A <
em class="citetitle">RFC 2104</
em>.
10139N/A<
div class="refsect1" lang="en">
10139N/A<
a name="id2649424"></
a><
h2>AUTHOR</
h2>
13468N/A<
p><
span class="corpauthor">Internet Systems Consortium</
span>
10139N/A<
table width="100%" summary="Navigation footer">
10139N/A<
td width="40%" align="left" valign="top">
10139N/A<
span class="application">genrandom</
span>�</
td>
10139N/A<
td width="40%" align="right" valign="top">�<
span class="application">nsec3hash</
span>