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I SHALL DEVOUR YOUR HEART AND FEAST ON YOUR SOUL (so don't bug me).


Jul
13
comment Why enable SMTP STARTTLS if OpenSSL is dangerous?
@supercat: well, you have just described "DHE" cipher suites as commonly used in SSL. With a DHE cipher suite, the server sends a DH public key that the server signs with its "permanent" private key (often some RSA private key). The server can create a new DH key pair for each connection ! It is not very expensive, and clients don't expect the key to stay the same; they don't record it anywhere.
Jul
13
answered Reversible Hash Function?
Jul
13
comment Why enable SMTP STARTTLS if OpenSSL is dangerous?
Private key operations take time about 1ms or so (depending on algorithm, key length, type of CPU, clock rate...). Context-switching and sending a short data element (e.g. a hash to be signed, or a signature) between two process on the same machine, or between a process and the kernel, is more a matter of a few micro-seconds, so we are talking about an overhead of less than 1% here, even when the CPU spends most of its time doing asymmetric crypto (which is a DoS situation, not something normal).
Jul
12
comment Why enable SMTP STARTTLS if OpenSSL is dangerous?
The "damage" from Heartbleed was really due to the panic which submerged so many people, rather than a specific technical detail. Yet there is value in isolating private keys out of the process address space. This is why Microsoft is trying to replace their old CryptoAPI with a new API called "CNG", because the latter allows for private keys to be stored in kernel space, thus out of reach of some vulnerabilities (this also prevents the keys from leaking to swap space).
Jul
11
awarded  Good Answer
Jul
11
answered Should I let a user know they have entered an unknown username or email address?
Jul
11
answered What does the pgp public key length depend on?
Jul
11
answered Byte swapping encryption algorithm security flaws?
Jul
11
comment Usefulness of bcrypt(UUIDv4())
This might be related to the fact that an UUID is 128 bits, but only 122 are random (the 6 other mostly encode the fact that the UUID is "v4"). In that sense, it "loses" 6 bits (not 4) or randomness. But that's hardly an issue -- 122 bits are still a lot more than is needed to defeat exhaustive search.
Jul
11
answered Usefulness of bcrypt(UUIDv4())
Jul
11
answered Why enable SMTP STARTTLS if OpenSSL is dangerous?
Jul
11
comment Would it be secure to generate random number using AES?
When /dev/urandom is not a good source of randomness on a given machine, nothing else is.
Jul
10
awarded  Nice Answer
Jul
10
comment What are the alternatives to ECDSA for an authentication protocol?
@user49555: at least libgcrypt implements RFC 6979 since version 1.6.0 (released on December 2013).
Jul
10
answered Would it be secure to generate random number using AES?
Jul
10
answered Is “the oft-cited XKCD scheme […] no longer good advice”?
Jul
10
answered What are the alternatives to ECDSA for an authentication protocol?
Jul
10
answered How to generate an unpredictable but short string?
Jul
10
answered Is it possible to use bitcoin miners to decrypt files/communication?
Jul
10
answered hparm -I /dev/sda does not report a Security section - should I be concerned?