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I have a node.js server that I'm configuring for TLS 1.2. I set the following options in the config of my https server:

ciphers: 'ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA256:AES128-GCM-SHA256:RC4:HIGH:!MD5:!aNULL',
honorCipherOrder: true,
secureProtocol: 'TLSv1_2_method'

I then ran cipherscan on the port it created and got this result:

prio  ciphersuite                  protocols  pfs                 curves
1     ECDHE-RSA-AES128-SHA256      TLSv1.2    ECDH,P-256,256bits  prime256v1
2     AES128-GCM-SHA256            TLSv1.2    None                None
3     ECDHE-RSA-RC4-SHA            TLSv1.2    ECDH,P-256,256bits  prime256v1
4     RC4-SHA                      TLSv1.2    None                None
5     ECDHE-RSA-AES256-GCM-SHA384  TLSv1.2    ECDH,P-256,256bits  prime256v1
6     ECDHE-RSA-AES256-SHA384      TLSv1.2    ECDH,P-256,256bits  prime256v1
7     ECDHE-RSA-AES256-SHA         TLSv1.2    ECDH,P-256,256bits  prime256v1
8     AES256-GCM-SHA384            TLSv1.2    None                None
9     AES256-SHA256                TLSv1.2    None                None
10    AES256-SHA                   TLSv1.2    None                None
11    CAMELLIA256-SHA              TLSv1.2    None                None
12    ECDHE-RSA-AES128-GCM-SHA256  TLSv1.2    ECDH,P-256,256bits  prime256v1
13    ECDHE-RSA-AES128-SHA         TLSv1.2    ECDH,P-256,256bits  prime256v1
14    AES128-SHA256                TLSv1.2    None                None
15    AES128-SHA                   TLSv1.2    None                None
16    CAMELLIA128-SHA              TLSv1.2    None                None
17    ECDHE-RSA-DES-CBC3-SHA       TLSv1.2    ECDH,P-256,256bits  prime256v1
18    DES-CBC3-SHA                 TLSv1.2    None                None

Certificate: trusted, 2048 bit, sha256WithRSAEncryption signature
TLS ticket lifetime hint: 7200
OCSP stapling: not supported
Cipher ordering: server
Curves ordering: server
Curves fallback: False

Fallbacks required:
big-SSLv3 config not supported, connection failed
big-TLSv1.0 config not supported, connection failed
big-TLSv1.1 config not supported, connection failed
big-TLSv1.2 no fallback req, connected: TLSv1.2 ECDHE-RSA-AES128-SHA256

Any idea why 'ECDHE-ECDSA-AES256-SHA384' is not my top priority cipher? It doesn't matter so much to me, but I would like to understand what I'm seeing better.

  • Have you tried asking e.g. Indutny on github? – Deer Hunter Aug 16 '15 at 20:41
  • 1
    Probably relevant: github.com/nodejs/node/issues/818 – Deer Hunter Aug 16 '15 at 21:08
  • Ok, probably comes down to my not really understanding the format of that string. I'll try tweaking it based on what I'm seeing in that discussion. – Ben Flynn Aug 16 '15 at 21:49
  • Ok, I adjusted my list and it is being obeyed. Seems as though ECDSA may not be supported, but that is not a problem. Thanks for the tip. – Ben Flynn Aug 16 '15 at 22:38
  • Ben, you may post an answer to your owm question if you fixed the problem. – Deer Hunter Aug 17 '15 at 2:23
2

ECDSA?

No ECDSA cert installed or no ECDSA-scan support in the tool you used, maybe?

Check with another tool. Or by hand on the command line with the openssl s_client command.

  • Yes, that makes sense. A combination of me not reading the screen carefully enough, not understanding the cipher string well enough, and not realizing the my cert is RSA. – Ben Flynn Aug 17 '15 at 15:36

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