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Hello Alex,<br>
This looks similar to:<br>
<a class="moz-txt-link-freetext" href="http://erlang.org/pipermail/erlang-questions/2016-September/090132.html">http://erlang.org/pipermail/erlang-questions/2016-September/090132.html</a><br>
<br>
Basically, there was a bug for AES encryption in snmp library
(exactly what you are pointing in your mail). You can fix it by
applying a patch that is attached in the above post.<br>
<br>
Best,<br>
Dominik Pawlak<br>
<br>
<div class="moz-cite-prefix">On 31.05.2017 10:10, Alex Anto Navis
Lawrence wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAMsDG5qEh7Nrpjs2mmvNCFEXTpMnUTLMKuZuZfUU1iZVRO_j+w@mail.gmail.com">
<div dir="ltr">
<div class="gmail_quote">
<div dir="ltr">Hello friends,
<div><br>
</div>
<div>I have been trying to make the SNMP v3 work with AES,
but couldn't. Please find the code in the below gist.</div>
<div><br>
</div>
<div>Erlang/OTP 19<br clear="all">
<div>Elixir: 1.4.2</div>
<div><br>
</div>
<div><a
href="https://gist.github.com/alexnavis/8eec113cabc47a43a5a6d1eb870352fb"
target="_blank" moz-do-not-send="true">https://gist.github.com/<wbr>alexnavis/<wbr>8eec113cabc47a43a5a6d1eb870352<wbr>fb</a><br>
</div>
<div><br>
</div>
<div><b>Problem:</b></div>
<div>SNMP packet is sent out but there is no response from
the server. Code gist has the working Net-SNMP shell
utility working command.</div>
<div>It fails in the receive block timeout since no packet
is received (I verified with wireshark). The same code
works if it is the DES algorithm.</div>
<div><br>
</div>
<div><b>Code:</b></div>
<div>
<p
style="box-sizing:border-box;margin-top:0px;margin-bottom:16px;color:rgb(36,41,46);font-family:-apple-system,system-ui,"Segoe
UI",Helvetica,Arial,sans-serif,"Apple Color
Emoji","Segoe UI Emoji","Segoe UI
Symbol"">From the erlang code for AES, it uses
Local EngineBoots and EngineTime to create the IV.
SaltFun() is a incremental value which is sent as part
of the authorizationParameters in the UDP headers. I
feel using local engineBoots and engineTime might be
wrong since the remote agent will not have any idea
about our snmp_manager boots and engine time. Any
thoughts on this ?</p>
<pre style="box-sizing:border-box;font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,Courier,monospace;font-size:11.9px;margin-top:0px;margin-bottom:16px;font-stretch:normal;line-height:1.45;word-wrap:normal;padding:16px;overflow:auto;background-color:rgb(246,248,250);border-radius:3px;color:rgb(36,41,46)"><code style="box-sizing:border-box;font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,Courier,monospace;font-size:11.9px;padding:0px;margin:0px;background:transparent;border-radius:3px;word-break:normal;border:0px;display:inline;overflow:visible;line-height:inherit;word-wrap:normal">snmp_usm.erl.
aes_encrypt(PrivKey, Data, SaltFun, EngineBoots, EngineTime) ->
AesKey = PrivKey,
Salt = SaltFun(),
IV = list_to_binary([?i32(<wbr>EngineBoots), ?i32(EngineTime) | Salt]),
EncData = crypto:block_encrypt(?BLOCK_<wbr>CIPHER_AES,
AesKey, IV, Data),
{ok, binary_to_list(EncData), Salt}.</code></pre>
<p
style="box-sizing:border-box;margin-top:0px;color:rgb(36,41,46);font-family:-apple-system,system-ui,"Segoe
UI",Helvetica,Arial,sans-serif,"Apple Color
Emoji","Segoe UI Emoji","Segoe UI
Symbol";font-size:14px;margin-bottom:0px">Any
pointers will be really helpful. Thanks.</p>
<span class="HOEnZb"><font color="#888888">
<p
style="box-sizing:border-box;margin-top:0px;color:rgb(36,41,46);font-family:-apple-system,system-ui,"Segoe
UI",Helvetica,Arial,sans-serif,"Apple
Color Emoji","Segoe UI
Emoji","Segoe UI
Symbol";font-size:14px;margin-bottom:0px"><br>
</p>
</font></span></div>
</div>
</div>
</div>
-- <br>
<div class="gmail_signature" data-smartmail="gmail_signature">
<div dir="ltr">Thanks,
<div>Alex Anto Navis. L</div>
</div>
</div>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
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</pre>
</blockquote>
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