<html>
<head>
<meta content="text/html; charset=UTF-8" http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<span class="im">The call crypto:block_decrypt(blowfish_cbc, ...</span><br>
<br>
ends up in C-function bf_cbc_crypt() in <br>
<br>
$ERL_TOP/lib/crypto/c_src/crypto.c<br>
<br>
which in turn calls OpenSSL functions BF_set_key() and
BF_cbc_encrypt().<br>
<br>
<br>
If you know the exact plain text to expect, have you tried doing<br>
the reverse with crypto:block_encrypt.<br>
<br>
What about trying the same with an unsensitive key that you can
share.<br>
<br>
Still don't understand what role IvSpec plays in all this.<br>
<br>
<br>
/Sverker, Erlang/OTP<br>
<br>
<br>
On 11/09/2015 02:17 PM, Bogdan Andu wrote:<br>
<blockquote
cite="mid:CAP7yTnwZiPHif=8jwpzZfn40=6uEYGbKnb_yQ8BCQBqM+-+tdg@mail.gmail.com"
type="cite">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<div dir="ltr">I have DataToBeDecrypted
<div><br>
and one-liner in erlang shell:<span class="im"><br>
<br>
crypto:block_decrypt(blowfish_cbc, hexstr2bin(Key), IV,
Rest).<br>
<br>
</span></div>
<div>where DataToBeDecrypted is formatted as follows:<br>
</div>
<div><br>
<<IvSpec:8/binary, IV:8/binary, Rest/binary>> =
DataToBeDecrypted<br>
<br>
</div>
<div>I can extract IvSpec = <<"RandomIV">>,<br>
<br>
</div>
<div>Next 8 octets is IV,<br>
<br>
</div>
<div>Rest should bet the actual quantity to be decrypted,<br>
<br>
</div>
<div>and the function call above fails to produce the plain text
expected,<br>
</div>
<div>only garbage<br>
<br>
</div>
Unfortunately Key is sensitive and cannot disclose the value.</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Mon, Nov 9, 2015 at 11:40 AM, Rad
Gruchalski <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:radek@gruchalski.com" target="_blank">radek@gruchalski.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>Bogdan,</div>
<div><br>
</div>
<div> I wonder if you can show us a minimum viable example.
</div>
<div>How do you encrypt, how do you decrypt. Can you present
such code?</div>
<div>
<p
style="font-family:Helvetica;font-size:10pt;margin-bottom:0cm">
</p>
<p
style="font-family:Helvetica;font-size:10pt;margin-bottom:0cm">
</p>
<p style="margin-bottom:0cm"> </p>
<p style="margin-bottom:0cm"><font color="#000000"><font
face="Helvetica, sans-serif"><font
style="font-size:9pt">Kind
regards,
<br>
Radek
Gruchalski<br>
</font></font></font><font face="Helvetica,
sans-serif"><font style="font-size:9pt"><a
moz-do-not-send="true"
href="mailto:radek@gruchalski.com" target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:radek@gruchalski.com">radek@gruchalski.com</a></a><a
moz-do-not-send="true"
href="mailto:radek@gruchalski.com" target="_blank">
</a></font></font><font
color="#0084d1"><font face="Helvetica, sans-serif"><font
style="font-size:9pt"><br>
</font></font></font><a moz-do-not-send="true"
href="http://de.linkedin.com/in/radgruchalski/"
target="_blank"><font color="#0084d1"><font
face="Helvetica, sans-serif"><font
style="font-size:9pt">de.linkedin.com/in/radgruchalski/</font></font></font></a><font
color="#000000"><font face="Helvetica, sans-serif"><font
style="font-size:9pt"><br>
<br>
</font></font></font><font color="#878787"><font
face="Helvetica, sans-serif"><font
style="font-size:8pt"><b>Confidentiality:<br>
</b></font></font></font><font color="#878787"><font
face="Helvetica, sans-serif"><font
style="font-size:8pt">This
communication is intended for the above-named
person and may be
confidential and/or legally privileged.<br>
If it has come to you in
error you must take no action based on it, nor
must you copy or show
it to anyone; please delete/destroy and inform the
sender
immediately.</font></font></font></p>
</div>
<div class="HOEnZb">
<div class="h5">
<p style="color:#a0a0a8">On Monday, 9 November 2015 at
10:38, Bogdan Andu wrote:</p>
<blockquote type="cite"
style="border-left-style:solid;border-width:1px;margin-left:0px;padding-left:10px">
<span>
<div>
<div>
<div dir="ltr">
<div>
<div>
<div>
<div>
<div>
<div><br>
</div>
hi,<br>
<br>
</div>
I really need some pointers about this
issue<br>
<br>
</div>
as i tried all kinds of combinations of
IV and body<br>
</div>
to be decrypted.<br>
<br>
</div>
Am i missing something or there is a bug in
cipher<br>
</div>
blowfish_cbc ?<br>
<div><br>
<div>
<div>
<div><br>
</div>
</div>
</div>
</div>
</div>
<div><br>
<div>On Thu, Nov 5, 2015 at 3:51 PM, Bogdan
Andu <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:bog495@gmail.com"
target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:bog495@gmail.com">bog495@gmail.com</a></a>></span>
wrote:<br>
<blockquote type="cite">
<div>
<div dir="ltr">
<div>
<div>
<div> Data to be decrypted
(arrived on socket, etc) is:<br>
<<IvSpec:8/binary,
IV:8/binary, Rest/binary>>
= EncryptedData<br>
<br>
</div>
IV is ectracted form the 8-byte
prepanded value preceding <br>
</div>
IvSpec which has the value RandomIV.<br>
<br>
</div>
decryption of Rest should be
initialized with IV.<br>
<br>
</div>
<div>
<div>
<div><br>
<div>On Thu, Nov 5, 2015 at 3:38
PM, Radoslaw Gruchalski <span
dir="ltr"><<a
moz-do-not-send="true"
href="mailto:radek@gruchalski.com"
target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:radek@gruchalski.com">radek@gruchalski.com</a></a>></span>
wrote:<br>
<blockquote type="cite">
<div>
<div
style="padding-left:16px;padding-right:16px;padding-bottom:8px">
<div>You say your data is:</div>
<div><br>
</div>
<div><<IvSpec>>
==
<<RandomIv>></div>
<div><br>
</div>
<div>But you read:</div>
<div><br>
</div>
<div>Is your data
<<IvSpec:8/binary,
IV:8/binary,
Rest/binary>></div>
<div><br>
</div>
<div>Should it not be
just:</div>
<div><br>
</div>
<div><<IV:8/binary,
Rest/binary>></div>
<div><br>
</div>
<div>?<br>
<br>
<div>Sent from <a
moz-do-not-send="true"
href="http://aka.ms/Ox5hz3" target="_blank">Outlook</a></div>
<br>
</div>
</div>
<div>_____________________________<br>
From: Bogdan Andu <<a
moz-do-not-send="true"
dir="ltr"
href="mailto:bog495@gmail.com"
target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:bog495@gmail.com">bog495@gmail.com</a></a>><br>
Sent: Thursday, November
5, 2015 2:26 p.m.<br>
Subject:
[erlang-questions]
blowfish cbc mode decrypt<br>
To: Erlang <<a
moz-do-not-send="true"
dir="ltr"
href="mailto:erlang-questions@erlang.org"
target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:erlang-questions@erlang.org">erlang-questions@erlang.org</a></a>>
<div>
<div><br>
<br>
<br>
<div dir="ltr">
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div> Hi, <br>
<br>
</div>
I have a
stream of data
called
EncryptedData
(with randomiv
header
specification).
<br>
I want to
decrypt
using: <br>
crypto:block_decrypt(blowfish_cbc,
hexstr2bin(Key),
IV, Rest). <br>
<br>
</div>
<div> where: <br>
</div>
<div> <br>
EncryptedData
is formatted
as follows: <br>
</div>
<<IvSpec:8/binary,
IV:8/binary,
Rest/binary>>
<br>
<br>
</div>
IvSpec ==
<<"RandomIV">>
<br>
<br>
</div>
However the
decryption
does not works
and garbage is
generated <br>
</div>
<div> (the
function ) .
<br>
</div>
<div> <br>
</div>
What could be
done given the
fact that IV
is an 8-byte
quantity <br>
</div>
the Key is
formatted
according to
crypto test
suites and is
16 bytes long
<br>
<br>
</div>
Am I missing
something? <br>
<br>
</div>
Thanks, <br>
<br>
</div>
Bogdan <br>
</div>
<br>
<br>
</div>
</div>
</div>
</div>
</blockquote>
</div>
<br>
</div>
</div>
</div>
</div>
</blockquote>
</div>
<br>
</div>
</div>
</div>
</span> </blockquote>
<div> <br>
</div>
</div>
</div>
</blockquote>
</div>
<br>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
erlang-questions mailing list
<a class="moz-txt-link-abbreviated" href="mailto:erlang-questions@erlang.org">erlang-questions@erlang.org</a>
<a class="moz-txt-link-freetext" href="http://erlang.org/mailman/listinfo/erlang-questions">http://erlang.org/mailman/listinfo/erlang-questions</a>
</pre>
</blockquote>
<br>
</body>
</html>