Re: [TLS] New Algorithm identifier for EDH > 1024 bits?
mrex@sap.com (Martin Rex) Mon, 30 September 2013 19:28 UTC
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To: Peter Gutmann <pgut001@cs.auckland.ac.nz>
Date: Mon, 30 Sep 2013 21:28:05 +0200
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Subject: Re: [TLS] New Algorithm identifier for EDH > 1024 bits?
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Peter Gutmann wrote: > Phillip Hallam-Baker <hallam@gmail.com> writes: > > >My understanding of the 1024 bit Ephemeral DH key issue is that it is not > >currently possible to use longer keys because a certain number of deployed > >Web servers will abort the connection if a client presents a longer key. > > > >Hmmm, wonder who made that decision... > > Could that be because of all of the TLS_DHE_DSS_* suites, with DSS limited to > 1024 bits so implementers also limited the matching DH to 1024 bits? Just > wondering what other reason there could possibly be for artificially limiting > the size to 1024 bits. The delay incurred by key generation maybe? The app-supplied credentials are either RSA or DSA. So for DHE, _everything_ has to be newly generated after process start and potentially in-band during the TLS handshake, unless the application caller has written some code that does generation out-of-band and installs/updates the DHE keying material regularly. -Martin
- [TLS] New Algorithm identifier for EDH > 1024 bit… Phillip Hallam-Baker
- Re: [TLS] New Algorithm identifier for EDH > 1024… Wan-Teh Chang
- Re: [TLS] New Algorithm identifier for EDH > 1024… Yngve N. Pettersen
- Re: [TLS] New Algorithm identifier for EDH > 1024… Yaron Sheffer
- Re: [TLS] New Algorithm identifier for EDH > 1024… Peter Gutmann
- Re: [TLS] New Algorithm identifier for EDH > 1024… Yoav Nir
- [TLS] DHE key derivation Yaron Sheffer
- Re: [TLS] DHE key derivation Michael D'Errico
- Re: [TLS] DHE key derivation Martin Rex
- Re: [TLS] DHE key derivation Daniel Kahn Gillmor
- Re: [TLS] DHE key derivation Michael D'Errico
- Re: [TLS] DHE key derivation Michael D'Errico
- Re: [TLS] DHE key derivation Michael D'Errico
- Re: [TLS] DHE key derivation Daniel Kahn Gillmor
- Re: [TLS] DHE key derivation Hanno Böck
- Re: [TLS] DHE key derivation Hanno Böck
- Re: [TLS] DHE key derivation Yaron Sheffer
- Re: [TLS] DHE key derivation Yoav Nir
- [TLS] Private Key Security [Was Re: DHE key deriv… Michael StJohns
- Re: [TLS] Private Key Security [Was Re: DHE key d… Martin Rex
- Re: [TLS] New Algorithm identifier for EDH > 1024… Martin Rex
- Re: [TLS] New Algorithm identifier for EDH > 1024… Daniel Kahn Gillmor