<div dir="auto"><div>Be aware that you just posted your certificate's private key, and thus you should regenerate a new keypair/certificate to use. Otherwise, anyone who can manipulate traffic to your machine can execute a man-in-the-middle attack.</div><div dir="auto"><div dir="auto"><br></div><div dir="auto">-Kyle H</div><br><br><div class="gmail_quote" dir="auto"><div dir="ltr" class="gmail_attr">On Fri, Feb 14, 2020, 07:40 Jason Schultz <<a href="mailto:jetson23@hotmail.com">jetson23@hotmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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Thank you for your response Thulasi, this helped. I'm posting this back to the OpenSSL users list in case it helps anyone else, and in case anyone can help with my additional questions. While waiting for responses, I've been able to find out how my certificate
and keys were generated. I'd like to walk through that to hopefully verify I'm handling things correctly.</div>
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First, here is how my EC parameters file was generated:</div>
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<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
openssl ecparam -name prime256v1 -genkey -out myecparamsfile.pem</div>
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And the resulting file:</div>
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<p style="margin-top:0px;margin-bottom:0px;margin:0in;font-family:"Courier New"">
M640A-SAIL:/etc/ssl # openssl ecparam -in <span style="font-family:"Courier New";background-color:rgb(255,255,255);display:inline!important">
myecparamsfile</span>.pem -text</p>
<p style="margin-top:0px;margin-bottom:0px;margin:0in;font-family:"Courier New"">
ASN1 OID: prime256v1</p>
<p style="margin-top:0px;margin-bottom:0px;margin:0in;font-family:"Courier New"">
NIST CURVE: P-256</p>
<p style="margin-top:0px;margin-bottom:0px;margin:0in;font-family:"Courier New"">
-----BEGIN EC PARAMETERS-----</p>
<p style="margin-top:0px;margin-bottom:0px;margin:0in;font-family:"Courier New"">
BggqhkjOPQMBBw==</p>
<p style="margin-top:0px;margin-bottom:0px;margin:0in;font-family:"Courier New"">
-----END EC PARAMETERS-----</p>
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# openssl ecparam -in myecparamsfile.pem -text</p>
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ASN1 OID: prime256v1</p>
<p style="margin-top:0px;margin-bottom:0px;margin:0in;font-family:"Courier New"">
NIST CURVE: P-256</p>
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-----BEGIN EC PARAMETERS-----</p>
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BggqhkjOPQMBBw==</p>
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-----END EC PARAMETERS-----</p>
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Is this good so far? Do I need the -genkey?</div>
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Then I take this file and use it when I generate my certificate and private key pair, here is the openssl command I used:</div>
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<span>openssl req -nodes -sha256 -newkey ec:/etc/ssl/private/myecparamsfile.pem -keyout mykeyout.pem -new -out mycertfileout.pem -config /etc/ssl/openssl.cnf -x509 -days 365 -outform pem<br>
</span>
<div>Generating a EC private key<br>
</div>
<div>writing new private key to 'mykeyout.pem'<br>
</div>
<div><parameter input snipped></div>
<div><br>
</div>
<div>And the resulting key:</div>
<div><br>
</div>
<div><span># cat mykeyout.pem<br>
</span>
<div>-----BEGIN PRIVATE KEY-----<br>
</div>
<div>MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgbfUwVhomun9Q5IAY<br>
</div>
<div>xTOAn+sDoXZ+k4UWkvUyfshPBJ6hRANCAAQsakFVUTV4JmfVJH31XOvHVhhBodnV<br>
</div>
<div>8evYCJSd2Jgo4uOomCSh3oekKL+Tia+LOmynygfvmneOX2YadoNr9uzH<br>
</div>
<div>-----END PRIVATE KEY-----<br>
</div>
<span></span><br>
</div>
<div><span># openssl ec -noout -text -in mykeyout.pem<br>
</span>
<div>read EC key<br>
</div>
<div>Private-Key: (256 bit)<br>
</div>
<div>priv:<br>
</div>
<div> 6d:f5:30:56:1a:26:ba:7f:50:e4:80:18:c5:33:80:<br>
</div>
<div> 9f:eb:03:a1:76:7e:93:85:16:92:f5:32:7e:c8:4f:<br>
</div>
<div> 04:9e<br>
</div>
<div>pub:<br>
</div>
<div> 04:2c:6a:41:55:51:35:78:26:67:d5:24:7d:f5:5c:<br>
</div>
<div> eb:c7:56:18:41:a1:d9:d5:f1:eb:d8:08:94:9d:d8:<br>
</div>
<div> 98:28:e2:e3:a8:98:24:a1:de:87:a4:28:bf:93:89:<br>
</div>
<div> af:8b:3a:6c:a7:ca:07:ef:9a:77:8e:5f:66:1a:76:<br>
</div>
<div> 83:6b:f6:ec:c7<br>
</div>
<div>ASN1 OID: prime256v1<br>
</div>
<div>NIST CURVE: P-256<br>
</div>
<span></span><br>
</div>
<div>And certificate:</div>
<div><br>
</div>
<div><span>M740A-PMM1:/etc/ssl # openssl x509 -text -in mycertfileout.pem<br>
</span>
<div>Certificate:<br>
</div>
<div> Data:<br>
</div>
<div> Version: 3 (0x2)<br>
</div>
<div> Serial Number:<br>
</div>
<div> e2:2f:c6:e4:bf:f1:de:20<br>
</div>
<div> Signature Algorithm: ecdsa-with-SHA256<br>
</div>
<div> Issuer: C=US, ST=<span style="font-family:Calibri,Helvetica,sans-serif;background-color:rgb(255,255,255);display:inline!important">NY</span>, L=<span style="font-family:Calibri,Helvetica,sans-serif;background-color:rgb(255,255,255);display:inline!important">Loc</span>,
O=<span style="font-family:Calibri,Helvetica,sans-serif;background-color:rgb(255,255,255);display:inline!important">Org</span>, OU=<span style="font-family:Calibri,Helvetica,sans-serif;background-color:rgb(255,255,255);display:inline!important">test</span>,
CN=<span style="font-family:Calibri,Helvetica,sans-serif;background-color:rgb(255,255,255);display:inline!important">My Name/emailAddress=</span><span style="margin:0px;font-family:Calibri,Helvetica,sans-serif;background-color:rgb(255,255,255);display:inline!important">test@example</span><span style="font-family:Calibri,Helvetica,sans-serif;background-color:rgb(255,255,255);display:inline!important">.com</span><br>
</div>
<div> Validity<br>
</div>
<div> Not Before: Feb 13 16:11:39 2020 GMT<br>
</div>
<div> Not After : Feb 12 16:11:39 2021 GMT<br>
</div>
<div> Subject: C=US, ST=NY, L=Loc, O=Org, OU=test, CN=My Name/emailAddress=<span style="font-family:Calibri,Helvetica,sans-serif;background-color:rgb(255,255,255);display:inline!important">test@example</span>.com<br>
</div>
<div> Subject Public Key Info:<br>
</div>
<div> Public Key Algorithm: id-ecPublicKey<br>
</div>
<div> Public-Key: (256 bit)<br>
</div>
<div> pub:<br>
</div>
<div> 04:2c:6a:41:55:51:35:78:26:67:d5:24:7d:f5:5c:<br>
</div>
<div> eb:c7:56:18:41:a1:d9:d5:f1:eb:d8:08:94:9d:d8:<br>
</div>
<div> 98:28:e2:e3:a8:98:24:a1:de:87:a4:28:bf:93:89:<br>
</div>
<div> af:8b:3a:6c:a7:ca:07:ef:9a:77:8e:5f:66:1a:76:<br>
</div>
<div> 83:6b:f6:ec:c7<br>
</div>
<div> ASN1 OID: prime256v1<br>
</div>
<div> NIST CURVE: P-256<br>
</div>
<div> X509v3 extensions:<br>
</div>
<div> X509v3 Subject Key Identifier:<br>
</div>
<div> D6:8A:F3:3B:4E:A1:F8:F8:34:C1:1B:7A:EC:BF:9B:58:7F:68:4A:D9<br>
</div>
<div> X509v3 Authority Key Identifier:<br>
</div>
<div> keyid:D6:8A:F3:3B:4E:A1:F8:F8:34:C1:1B:7A:EC:BF:9B:58:7F:68:4A:D9<br>
</div>
<div><br>
</div>
<div> X509v3 Basic Constraints:<br>
</div>
<div> CA:TRUE<br>
</div>
<div> Signature Algorithm: ecdsa-with-SHA256<br>
</div>
<div> 30:44:02:20:37:f0:f7:f7:4a:b4:8e:8f:64:72:e4:d1:31:9f:<br>
</div>
<div> a1:36:c5:5d:f3:42:4c:24:37:75:cf:b6:55:b0:66:1b:6e:63:<br>
</div>
<div> 02:20:39:18:81:f8:6c:86:3a:57:74:05:cc:99:6c:d9:dc:6a:<br>
</div>
<span> a2:20:98:4c:66:a1:97:d1:c7:ea:42:b4:01:1a:f7:b2</span><br>
</div>
<div><span><br>
</span></div>
<div>Then I call the APIs as described in my first email to use them:</div>
<div><br>
</div>
<div>
<pre style="font-family:courier,"courier new",monospace;font-size:14px;margin:0px;background-color:rgb(255,255,255)">ctx = SSL_CTX_new(TLS_method());</pre>
<pre style="font-family:courier,"courier new",monospace;font-size:14px;margin:0px;background-color:rgb(255,255,255)">status = SSL_CTX_use_PrivateKey_file(ctx,<keyfile>,SSL_FILETYPE_PEM);
status = SSL_CTX_use_certificate_file(ctx, ,<certfile>,SSL_FILETYPE_PEM);</pre>
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<div>
<pre style="font-family:courier,"courier new",monospace;font-size:14px;margin:0px;background-color:rgb(255,255,255)">// Verify the cert and key are a pair
status = SSL_CTX_check_private_key(ctx);</pre>
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<div>Then call the APIs to set the curves and allow the server to pick the appropriate curve for the client:</div>
<div><br>
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<div>
<pre style="font-family:courier,"courier new",monospace;font-size:14px;margin:0px;background-color:rgb(255,255,255)">status = SSL_CTX_set1_curves_list(ctx, "P-521:P-384:P-256");
status = SSL_CTX_set_ecdh_auto(ctx, 1);</pre>
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</div>
<div>That should be it, right? The EC parameters file has been used to generate the private key, it does not need to be read in by an API call.</div>
<div><br>
</div>
<div>With the steps above, I get a successful TLS connection from a client using ECDHE-ECDSA-AES256-GCM-SHA384.</div>
<div><br>
</div>
<div>And yes, I think my main confusion was on what to do with the DH parameters file. I thought using ECDHE key exchange was similar to DSA with DH. With ECDHE, I don't need to read in a parameters file at all.</div>
<div><br>
</div>
<div>If there's anything wrong above, please let me know, otherwise, thanks for all the help!</div>
<div><br>
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<span></span></div>
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<div id="m_7334009758260241939x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> Thulasi Goriparthi <<a href="mailto:thulasi.goriparthi@gmail.com" target="_blank" rel="noreferrer">thulasi.goriparthi@gmail.com</a>><br>
<b>Sent:</b> Wednesday, February 12, 2020 8:29 AM<br>
<b>To:</b> <a href="mailto:jetson23@hotmail.com" target="_blank" rel="noreferrer">jetson23@hotmail.com</a> <<a href="mailto:jetson23@hotmail.com" target="_blank" rel="noreferrer">jetson23@hotmail.com</a>><br>
<b>Cc:</b> <a href="mailto:rsalz@akamai.com" target="_blank" rel="noreferrer">rsalz@akamai.com</a> <<a href="mailto:rsalz@akamai.com" target="_blank" rel="noreferrer">rsalz@akamai.com</a>><br>
<b>Subject:</b> Re: Questions about using Elliptic Curve ciphers in OpenSSL</font>
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<div>
<div dir="auto">To clarify further, EC keys can be generated from either explicit (group) parameters or named curves which are standardized numbers to specific group parameters.
<div dir="auto"><br>
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<div dir="auto">Explicit/Custom EC parameters are not recommended/convenient/usual. Your key contains parameters in the form of a named curve (p-256).</div>
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<div dir="auto">You are probably getting confused between dhparam used to generate ephemeral keys for DHE based key exchange and EC curve selection for ECDHE based key exchange. </div>
<div dir="auto"><br>
</div>
<div dir="auto">Curve selection for ECDHE will be done from the list of curves offered by the client and can be different from the curve used in the server's certificate(ECDSA).</div>
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<div dir="auto">Thanks,</div>
<div dir="auto">Thulasi.</div>
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<div dir="ltr">On Tue, 11 Feb, 2020, 23:24 Salz, Rich via openssl-users, <<a href="mailto:openssl-users@openssl.org" target="_blank" rel="noreferrer">openssl-users@openssl.org</a>> wrote:<br>
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<p style="margin-top:0px;margin-bottom:0px">I believe you just load your ECDSA cert and the other stuff – Dhparams!! – is not needed.<u></u><u></u></p>
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