SSL operation failed with code 1: dh key too small (1)

OpenSSH 6.2 offers the following key exchange algorithms by default. Ecdh-sha2-nistp256 ecdh-sha2-nistp384 ecdh-sha2-nistp521 diffie-hellman-group-exchange-sha256 diffie-hellman-group-exchange-sha1 diffie-hellman-group14-sha1 diffie-hellman-group1-sha1 The group size of the first three is obvious. The same holds for the last two. Solving Di e-Hellman problem solves the decision Di e-Hellman problem. As is usual, we denote by Alice and Bob, two people trying to set up a private key over an insecure channel to communicate securely and Oscar an adversary is eavesdropping. In this paper the shared secret or the private key is an element of a nitely presented group G. Breaking Diffie-Hellman with Massive Precomputation (Again) The Internet is abuzz with this blog post and paper, speculating that the NSA is breaking the Diffie-Hellman key-exchange protocol in the wild through massive precomputation. I wrote about this at length in May when this paper was first made public. (The reason it's news again is that the paper was just presented at the.

I am connecting to my database Google Cloud SQL via SSL. I use codeigniter 3.0 to do so, although the mysqli driver is a bit modified to allow this functionality.

It's been working well for months. However it just started to return this warning:

I'm assuming DH Key is too small is the main problem, but I have no idea what that means. I've googled Diffie–Hellman key exchange, along with the message 'key too small' but I haven't had much luck.

Is this a sign that the keys on the server have been tampered with? I've checked the last-modified dates on them -- no abnormal recent access.

It could be that my server did some upgrading to PHP or their server configuration, which may result in this breaking, but I wanted to check and make sure that it wasn't something else.

Thanks for any insight / readable material on the subject.

The error number you are interested in is the OpenSSL error 0x14082174.

The SSL3_CHECK_CERT_AND_ALGORITHM is usually seen when enabling export grade ciphers. It may be showing up again in non-export grade negotiations due to Logjam (see below).

I'm assuming DH Key is too small is the main problem, but I have no idea what that means. I've googled Diffie–Hellman key exchange, along with the message 'key too small' but I haven't had much luck.

That's due to the recent Logjam attack from the paper Imperfect Forward Secrecy: How Diffie-Hellman Fails in Practice .

You should use 2048-bit Diffie-Hellman groups or larger. You should not be using 512-bit or 1024-bit Diffie-Hellman groups.

The first thing to check for is your cipher list string. It should be similar to:

It will avoid the export grade ciphers, and use modern ciphers. But you will also need to ensure your DH callback is not using a weak/small field size. For that, you need to check the server configuration.

Some folks are 'solving' the issue with kRSA . kRSA is a key transport scheme, not a key agreement scheme. The RSA key transport scheme does not provide forward secrecy, and its use is usually discouraged. In fact, its going to be removed from TLS 1.3.

I can only say 'usually discouraged' because it depends on the data being protected. If you have SSL/TLS to guard downloads of a publicly available file, then its probably OK to use. If your website has a login, then its probably a little risky to use it because the password is secret data (unlike the publicly downloadable file).

To avoid key transport and pass those Qualsys SSL Labs tests for web server configurations and forward secrecy, use:

In your Apache configuration file, it would look like so: R2r ableton mac not working authorazation file invalid.

I seem to recall wget rejected small groups quite some time before the paper was released. It might make a good test case for your site.

There's also an improved sslscan , which tests for lots of things. That might make a good QA tool, too.

PyDHE is an instructional implementation of the Diffie-Hellman key exchange protocol in Python.

DiffieHellman.py contains a functional implementation of the protocol, and SimpleDHE.py includes a simplified example of the protocol's steps.

Disclaimer

PyDHE is provided as a demonstration of the Diffie-Hellman key exchange protocol. Per the GPL, it is provided without any warranty or implication of fitness for a purpose.

WARNING: The code in this project is for instructional purposes only. No matter how smart you might think you are, it's unwise to use homebrew encryption code in sensitive or production environments.

Diffie Hellman Explained

If you need real security, use an established, audited and thoroughly tested encryption package like PolarSSL, GNUTLS or NaCl. Many established encryption libraries include python bindings.

Example

The following code performs a complete exchange, including key generation using SHA-256:

Specifying your own parameters

To specify a different generator, prime group or private key size, specify them when calling DiffieHellman():

Diffie Hellman Routines Generate_key Key Size Too Small Feet

The class initializer does some basic sanity checks on supplied values.

Security

The DiffieHellman class uses parameters recommended by RFC 3562 for generation of a 256-bit key. Check the spec for other key sizes and options.

License

Diffie Hellman Generator

This program is free software: you can redistribute it and/or modifyit under the terms of the GNU General Public License as published bythe Free Software Foundation, either version 3 of the License, or(at your option) any later version.

This program is distributed in the hope that it will be useful,but WITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See theGNU General Public License for more details.

Diffie Hellman Routines Generate_key Key Size Too Small Video

You should have received a copy of the GNU General Public Licensealong with this program. If not, see http://www.gnu.org/licenses/.