[cryptography] Using same key for ECDSA and ECIES

2013-09-20 Thread Dominik Schürmann
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 I am wondering if it is okay to use the same asymmetric ECC key for ECDSA and ECIES. Given that the signing and encryption algorithms are not related like in RSA, I assume it is okay to use the same key for both operations. Are there any things I

Re: [cryptography] Using same key for ECDSA and ECIES

2013-09-20 Thread Dominik Schürmann
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 20.09.2013 17:17, Paterson, Kenny wrote: It is technically secure. See: http://eprint.iacr.org/2011/615 Thanks you so much for this paper, it's even mostly understandable with some basic knowledge of attack models :) Even so, I would not

Re: [cryptography] Using same key for ECDSA and ECIES

2013-09-20 Thread Dominik Schürmann
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 20.09.2013 22:09, Jeffrey Walton wrote: Crypto++ has the schemes and Dr. Bernstein's curve. The library is available on all major Linux and BSD platforms. I am using Crypto++ already, but I can't find ed25519 anywhere in the library. FYI: The

Re: [cryptography] skype backdoor confirmation

2013-05-23 Thread Dominik Schürmann
They have implemented ZRTP for end to end security. It works with a diffie hellman key exchange, while protecting against man-in-the-middle attackers by comparing Short Authentication Strings (SAS). When you know the voice of the other person you can exclude Eve. see

Re: [cryptography] skype backdoor confirmation

2013-05-23 Thread Dominik Schürmann
commit (e.g. send H(N,g^x)) prior to sending their g^x to avoid the latter problem? If so, then what's the use of the SAS? Sorry if all those questions are trivial... Wasa On 23/05/2013 19:05, Dominik Schürmann wrote: They have implemented ZRTP for end to end security. It works

Re: [cryptography] skype backdoor confirmation

2013-05-22 Thread Dominik Schürmann
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi folks, we recently wrote a small section about skype with some references: http://sufficientlysecure.org/uploads/skype.pdf Interesting references (from 2005, 2006): http://www.ossir.org/windows/supports/2005/2005-11-07/EADS-CCR_Fabrice_Skype.pdf