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Pentester, ex-developer, security researcher, reverse engineer, electronics tinkerer, internet activist, zombie eradicator, promulgator of useless facts, shrubbery inspector, bacon aficionado, devourer of donuts.

Strengths: Security, Crypto, Win32 API, C#, .NET, PHP, x86 assembly

All answers and comments are encrypted with ROT256-ECB.

Opinions are my own. Advice provided with no warranty.


Mar
20
comment Reducing hash output length
I still don't follow why you need to shrink the size of the hash down to 10 bytes. What's the reasoning behind this? You've asked whether it's "reasonably" secure "for your needs", but you haven't defined your needs, your threat model, your application's function, or the reason for reducing the hash size in the first place.
Mar
20
comment Reducing hash output length
CRC is not a cryptographically secure measure against modification. It's a checksum designed to detect corrupted data, not forging.
Mar
20
comment Reducing hash output length
@user30024 Thomas didn't say collisions don't matter. He's saying there's a difference between a preimage and a collision. In your case you're talking about checking for modified input (collisions matter, preimages are irrelevant) whereas that question concerned hashing passwords (preimages matter, collisions are mostly irrelevant).
Mar
20
comment Reducing hash output length
@user30024 Of course collisions are an issue. If there are collisions, you have a different message which is accepted as correct. Why do you want to reduce it, anyway? 20 bytes isn't exactly a lot to store or transmit.
Mar
20
comment is return-to-libc attacks possible Now?
Ah, it's a PLT.
Mar
20
comment Help understanding VPN
This doesn't really answer the question, beyond a (pretty poor) definition of the term "VPN", which you've copied verbatim from the site.
Mar
20
comment Cross Origin Resource Sharing question
How are you hosting your local code? If it's just as a direct file path into your browser, it may ignore SOP as you've not got an origin. Keep in mind that the SOP for CORS is browser-enforced, not server-enforced.
Mar
20
comment Is this a sensible way to encrypt user data?
@StuartP.Bentley scrypt will likely be used as a KDF to derive a key from the user's password.
Mar
20
comment is return-to-libc attacks possible Now?
The linker optimisation mentioned there isn't exclusive to Microsoft toolchains. Actually - can you post the disassembly that you've seen? It may be a direct syscall rather than an actual call to system().
Mar
20
comment Are there different degrees of “confidentiality”? What is the best way for a psychologist to maintain confidentiality of communications with patients?
@StanShunpike SMS is cleartext, so using it to transfer patient records is a HIPAA violation. Same goes for standard pagers. Voice communications over cellular networks are encrypted, and their contents are protected legally (wiretapping laws), so I would imagine you'd be ok with that. Though I'd refrain from leaving sensitive information about patient care specifics on voicemail regardless - just ask them to call you back to discuss things.
Mar
20
comment How Secure is my Application?
It's not as trivial as pulling it off the wire. Note that you can still encrypt the traffic inside HTTPS if you're trying to avoid the user getting access to the binaries. However, it seems you're trying to implement what amounts to a DRM system, which is inherently impossible: the user's machine is their own to do with as they wish, so they will get access if they want. In fact, all they need to do is write their own client that pulls down the binaries and saves them. You can't stop that - you can only make it a little harder.
Mar
20
comment is return-to-libc attacks possible Now?
You're probably running into a linker optimisation.
Mar
20
comment Are there different degrees of “confidentiality”? What is the best way for a psychologist to maintain confidentiality of communications with patients?
HIPAA applies if you're handling or transmitting patient data (assuming you operate in America). Emailing it unencrypted would not be considered compliant.
Mar
20
comment Are there additional security risks posed by rooting an Android device?
@RockPaperLizard Any standard Android pentesting guide would cover it, but your primary threats are likely to be from poor IPC code.
Mar
19
comment card.io & PCI DSS v3.0
That's useful to know - I wasn't aware there was any ruling on audio recordings of the data. More ammunition for getting people to do it right!
Mar
19
comment card.io & PCI DSS v3.0
I have come across organisations who attempted to "thwart" PCI-DSS and similar requirements by only storing images of the card front, to use the "we don't store PAN" argument, but (surprise surprise) their QSA did not sign off on it at all. At the end of the day, they are storing payment card information which is covered by regulatory requirements. Doesn't matter whether the PAN is stored as text, a cell in a spreadsheet, a JPEG, or whatever - it's still card information.
Mar
19
comment What email addresses are treated as trusted?
Unfortunately I don't think there's a canonical all-encompassing list - RFC2142 is where I'd have started too. You'd have to ask the major CAs and cross your fingers. Yet another fun facet of PKI.
Mar
19
comment Is my data secure in locked screen if I use bitlocker
I think you mean "brute force" rather than "DDOS".
Mar
19
comment Is android's FDE secure from offline attacks?
Ah, according to this it's a feature new to Android Lollipop (5.x).
Mar
19
comment Sans security courses: How are self study courses certified?
You're probably better off emailing SANS with this kind of question.