CodesInChaos

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bio	website	github.com/CodesInChaos
	location	Munich, Germany
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Jabber/XMPP: CodeInChaos@jabber.ccc.de
IRC: CodesInChaos on freenode
Email: My nick on gmail
Blog: codesinchaos.wordpress.com
GitHub: github.com/CodesInChaos
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	5,964 reputation	bio	website	github.com/CodesInChaos	visits	member for	1 year, 10 months
1927 badges		location	Munich, Germany		seen	36 mins ago

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Jul 27	revised	How secure is my OTP program? edited tags
Jul 27	revised	Can I jettison MAC if I already have SHA1(M)? removed security tag
Jul 26	revised	Can I pre-define the points in Shamir's Secret Sharing algorithm edited tags
Jul 26	asked	Purpose of outer key in HMAC
Jul 26	comment	Are mouse movement coordinates useful as a seed for a RNG? A 64 bit seed is far too small to be secure. And a single mouse position doesn't even have close to 64 bits of entropy. It doesn't even have 20 bits of entropy.
Jul 26	comment	Are mouse movement coordinates useful as a seed for a RNG? Why don't you just use the random number generator built into your operating system?
Jul 25	comment	Signature and Timestamp for Long Term Document Archival Question Aren't there some timestamp services that are based on publishing hashes?
Jul 22	comment	Using same keypair for Diffie-Hellman and signing The master key approach doesn't help either, since I try to minimize the size of the public key. I considered using the hash of two separate public keys, but that's annoying in some of my intended uses. After reading the paper I linked, I think the risk of using EC-DH + EC-Schnorr is acceptable compared to the risk of mistakes in other security relevant parts of the protocol and implementation.
Jul 22	comment	Using same keypair for Diffie-Hellman and signing The first distinction is not between encryption and signatures, it's between authentication and confidentiality keys. In particular if you authenticate emails using a key-exchange based algorithm[Which I prefer over signatures], it has the same life cycle as a key used for signing.
Jul 22	comment	Can ECDSA signatures be safely made “deterministic”? Related blog entry: Surviving a bad RNG Scroll down to ECDSA signatures
Jul 22	revised	Using same keypair for Diffie-Hellman and signing added 164 characters in body; edited tags
Jul 22	answered	Using same keypair for Diffie-Hellman and signing
Jul 21	comment	Can I jettison MAC if I already have SHA1(M)? @Fixee If you validate the padding first, and only then hash, and attacker might be able to use that to decrypt the message, even if he can't replace it by his own.
Jul 21	awarded	Yearling
Jul 21	answered	Can I jettison MAC if I already have SHA1(M)?
Jul 21	comment	Uncompress the winRar password protected file without password. (not brute force attacking) The method of encryption is less important. The interesting part is what kind of KDF WinRAR uses,
Jul 20	revised	Is there difference between Algebraic Homomorphic Encryption and Fully Homomorphic Encryption Schemes? deleted 2 characters in body; edited title
Jul 19	comment	Is there any recent cryptographic algorithm especially designed for low-level processors? Where does the plaintext come from? Does it get generated by the PC program?
Jul 19	comment	Is there any recent cryptographic algorithm especially designed for low-level processors? What kind of algorithm do you need? Symmetric encryption? a hash function? key-exchange? signatures? MAC? Authenticated encryption?
Jul 18	comment	Other than brute force, are there any attacks on Threefish-512 using only a single known plaintext block? Both attacks only work on reduced round ThreeFish, and not on the full Threefish. The first one only works that well on older versions of Threefish.