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


2d
comment Does TCP/IP protocol offer a reliable way of determining who the actual sender was?
When you use a proxy, you are not using a fake IP address -- you are using the real IP address of the machine which does the proxying work for you. Here, we are talking about an attacker who could take the control of an infrastructure router and can see IP packets destined for a whole network (not the one where the attacker has his own machine). This is more power than is available to the bulk of amateur attackers.
2d
comment How many Stack Exchange logins should I have?
The logic is simple: if you want to minimize the risks of hostile hijack, have only one login. If you want to minimize the risks of being locked out, have at many as possible. This is a trade-off, and only you can make that decision. (However, one possible "login" option is through stackexchange themselves, which is unlikely to close independently of the site itself, so maybe "just one, the one provided by stackexchange" would be the optimal spot.)
Apr
15
comment One computer with multiple OSs in different drives
Actually flashing the BIOS does not require a reboot; it just is that the BIOS reflashing utilities prefer it when there is no running OS at that time (to avoid untimely accesses), and the post-flash reboot is to make sure that the new BIOS code is used. However, the hardware itself has no notion of a "reboot" and warm-flashing is possible -- not recommended, but virus writers don't like to play safe anyway (especially with your hardware).
Apr
15
comment One computer with multiple OSs in different drives
A virus which infects hardware (e.g. the motherboard) must do things which are specific to that hardware. That does not mean that it does not happen... only that it will entail more work for the virus writer.
Apr
15
comment Why are security-crucial software written in unsafe languages?
Big integers are not easy to use in the absence of automatic memory management (the GC). Many people also fear that making the default "int" type a big integer would incur intolerable overhead (which is mostly untrue in practice, if you do it properly, i.e. encoding small integers as sort-of pointers). Python, and some Scheme dialects, use big integers by default.
Apr
15
comment Why are security-crucial software written in unsafe languages?
In my case, the JVM (that I wrote my self) was of the AOT kind: translation of bytecode (not Java source) to C code, compilation with a C compiler. Compared to native code for computing intensive tasks (e.g. encryption), the slowdown is a factor of 2 to 4. For big integers too -- at least on 32-bit ARM and PowerPC; on 64-bit x86, the factor rises to about 6 due to the 64x64->128 multiplication opcode that cannot be used from Java (whose biggest integer type is 64 bits).
Apr
15
comment Why are security-crucial software written in unsafe languages?
The hardware was a HSM, it had a cryptographic accelerator for RSA. "Native math" would not have been sufficient, by far. Note that the symmetric cryptography of the SSL connections was pure Java.
Apr
14
comment Are there “secure” languages?
But you had that kind of box about the "standard C library"... which is formally part of the language. Similarly, you never had a popup about the Java compiler being insecure, only the runtime support code.
Apr
14
comment Can Heartbleed be used to obtain memory from other processes?
No, indeed, the quote about mmap() does not imply reading memory from another process. What it implies is that blocks allocated from areas obtained through mmap() will be located in somewhat random places in the address space, whereas blocks from sbrk() have a more deterministic emplacement.
Apr
11
comment Why don't more websites implement Perfect Forward Secrecy?
BEAST has been mitigated client-side in many ways, but some widely used "test your server" sites will award a "A+" mark only if your server enforces RC4 whenever possible. If you want to conclude that such test sites simply make problems worse... well, you would be right.
Apr
11
comment What part of the browser is typically attacked?
The human user is the part which is most often compromised.
Apr
11
comment Firefox can import the .p12 format, but that contains a private key? Isnt this a security risk?
I have seen one bank distributing certificates to its clients, but that's still pretty rare. For a long time, certificate handling by browsers used very ugly popups, which did not help in making client certificates popular.
Apr
11
comment Firefox can import the .p12 format, but that contains a private key? Isnt this a security risk?
If you have a private key you can sign what you want, but if you want to play the role of a CA and issue certificates which are accepted by other people, then these other people must trust your public key in a CA role, which usually means that your public key is in a certificate, signed by another CA (that they trust), and, crucially, that certificate has the "is CA" mark in it (in the Basic Constraints extension, see the RFC). Existing commercial CA won't sell you such a certificate (or only for a wheelbarrow of money bills).
Apr
9
comment Should I change all my passwords due to heartbleed
It is no more (and no less !) necessary to change all passwords due to this bug, than it was for all the previous bugs which occurred over the years and allowed just as well data to leak or, even worse, complete hostile control. And we did not previously. So either everybody got it wrong for the last 30 years and we really should have reset all passwords for all servers in the world several times per year; or else somebody might be exaggerating a bit the specific case of this particular bug.
Apr
9
comment Heartbleed - Blown out of proportion?
Well, not really: you get a buffer overrun, so the server will read whatever bytes are there. But this can fall in an unallocated page, triggering a page fault and thus a crash of the server process. Thus, it is not 100% reliable, and neither is it 100% stealthy.
Apr
9
comment Why does TLS need an explicit heartbeat protocol?
Instead of sending a SSL record with n bytes of data, a client or server sends two records, the first one containing 1 byte, the second containing the remaining n-1 bytes. This allows for some "randomization" of the IV for CBC encryption, which defeats BEAST. Theoretically, a 0/n split would have worked, but at least IE 6.0 crashed on a zero-length record.
Apr
8
comment What was so dangerous about PGP that its creator was charged in court for it?
Maybe not exactly the same time. PGP is from the early 1990s, not the 1960s. Yet the legal details mattered: Zimmerman managed to legally export his code by printing it as a book (I have seen it: source code in a big, clear monospace font, and a big "scan this book" banner on the cover).
Apr
7
comment Are SSL encrypted communications through a company network safe?
The point of SSL is to keep outsiders out, yes.
Apr
4
comment Is the Station-to-Station protocol secure?
"Signature public key" = "public key fit for use in a signature algorithm". E.g. DSA, ECDSA... such public keys do not necessarily support asymmetric encryption or key exchange. It so happens that the most used asymmetric encryption algorithm (RSA) and the most used signature algorithm (RSA) share the same kind of key, allowing a "RSA key" to be used for both usages (although you do not necessarily want to), but that's not the general case for all algorithms cryptographers have come up with.
Apr
4
comment Is the Station-to-Station protocol secure?
They know each other signature public keys. A public key is not necessarily fit for asymmetric encryption. Moreover, using a new DH key pair on-the-fly grants forward secrecy.