<div dir="ltr">Hi Dominik,<div><br></div><div>Thanks a lot for the help. I was on the same line of fix based on <a href="https://www.ietf.org/rfc/rfc3826.txt">RFC-3826</a> (3.1.2.1. AES Encryption Key and IV) where I got the response and got stuck with decryption problem.</div><div><br></div><div>Now I saw the patch and applied the remaining changes(<a href="https://github.com/alexnavis/otp/tree/fix_snmp_v3_aes">git</a>) on decryption got the whole thing workings. Thanks a lot for your help, you saved a lot for me. 👍</div><div><br></div><div>Any idea on this why this is not fixed in latest erlang code. ?. Can i be any help to make this to raise for a PR for the same. ?</div><div><br></div><div>Thanks,</div><div>Alex</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, May 31, 2017 at 7:41 PM, Dominik Pawlak <span dir="ltr"><<a href="mailto:dominik_pawlak@yahoo.co.uk" target="_blank">dominik_pawlak@yahoo.co.uk</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
Hello Alex,<br>
This looks similar to:<br>
<a class="m_4988979721684751569moz-txt-link-freetext" href="http://erlang.org/pipermail/erlang-questions/2016-September/090132.html" target="_blank">http://erlang.org/pipermail/<wbr>erlang-questions/2016-<wbr>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<div><div class="h5"><br>
<br>
<div class="m_4988979721684751569moz-cite-prefix">On 31.05.2017 10:10, Alex Anto Navis
Lawrence wrote:<br>
</div>
</div></div><blockquote type="cite"><div><div class="h5">
<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">https://gist.github.com/alexna<wbr>vis/8eec113cabc47a43a5a6d1eb87<wbr>0352fb</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>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(EngineBoo<wbr>ts), ?i32(EngineTime) | Salt]),
EncData = crypto:block_encrypt(?BLOCK_CI<wbr>PHER_AES,
AesKey, IV, Data),
{ok, binary_to_list(EncData), Salt}.</code></pre>
<p>Any
pointers will be really helpful. Thanks.</p>
<span class="m_4988979721684751569HOEnZb"><font color="#888888">
<p><br>
</p>
</font></span></div>
</div>
</div>
</div>
-- <br>
<div class="m_4988979721684751569gmail_signature" data-smartmail="gmail_signature">
<div dir="ltr">Thanks,
<div>Alex Anto Navis. L</div>
</div>
</div>
</div>
<br>
<fieldset class="m_4988979721684751569mimeAttachmentHeader"></fieldset>
<br>
</div></div><pre>______________________________<wbr>_________________
erlang-questions mailing list
<a class="m_4988979721684751569moz-txt-link-abbreviated" href="mailto:erlang-questions@erlang.org" target="_blank">erlang-questions@erlang.org</a>
<a class="m_4988979721684751569moz-txt-link-freetext" href="http://erlang.org/mailman/listinfo/erlang-questions" target="_blank">http://erlang.org/mailman/<wbr>listinfo/erlang-questions</a>
</pre>
</blockquote>
<br>
</div>
</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr">Thanks,<div>Alex Anto Navis. L</div></div></div>
</div>