2,745 reputation
820
bio website touset.org
location San Francisco, CA
age 31
visits member for 2 years, 8 months
seen 2 hours ago

Cyclist. Rubyist.


1d
answered How can I stop an account I don't control from sending spam email in my name to my contacts?
Apr
13
comment More secure curve than Curve25519
We don't always use 256-bit ciphers. AES-128 is highly used, and is still (and will for the foreseeable future continue to be) considered a perfectly reasonable option for any new cryptosystem. In the absence of any specific 256-bit requirement, many would argue that AES-256 over AES-128 is simply wasted CPU cycles.
Apr
10
comment Source code as password
Just use a password manager like KeePass, LastPass, or 1Password. This is essentially a solved problem.
Apr
8
revised Is there any reason for using private key 2 times when creating security hash?
added 11 characters in body
Apr
7
answered Is there any reason for using private key 2 times when creating security hash?
Apr
7
comment Is there any reason for using private key 2 times when creating security hash?
This is a crude attempt at constructing an HMAC. I would hesitate to use such a payment system; if this is the quality of the cryptography they display publicly, the quality they use internally is certainly worse.
Apr
7
comment Is there any reason for using private key 2 times when creating security hash?
This is not strictly true. This construct (crudely) guards against length extension attacks, where an attacker knowing H(m) but not m can generate H(m+p+a) where p is the padding used by the hash function and a is attacker-controlled. Since the attacker doesn't know the secret key being used, he can't ensure his message ends with it. The real solution to this is to use the correct cryptographic construct: a MAC. More specifically, they probably want an HMAC.
Apr
7
comment How secure is MD5 for TLS message authentiaction?
RSA is not being removed from TLS 1.3. Static key exchange with RSA (and DH) is.
Apr
7
answered How secure is MD5 for TLS message authentiaction?
Apr
7
comment How secure is MD5 for TLS message authentiaction?
Downvoted for RSA FUD. RSA is not broken, if you use appropriate key sizes (>= 2048 bits)
Mar
30
comment Is it possible to make a more secure random number generator algorithm by XORing two or more less secure random number algorithms?
It's possible to improve two bad ones (for example, two truly random numbers which were provided and recorded by the NSA and GCHQ respectively, who for the sake of argument have no ability to communicate with each other or the rest of the world whatsoever). It's also possible (and dramatically more likely) for the combined construct to either fail to improve the security or worse, to worsen security when compared to each independently (like the LCG example in the post).
Feb
24
comment Could overlapping SHA256 hash begin to loop at some point?
The user submits their guess before they know anything about the outcome of the roll. What's the opportunity for a user to cheat?
Feb
23
comment Could overlapping SHA256 hash begin to loop at some point?
If it's a simple dice game, it's likely that all you need to do is perform a simple commitment scheme prior to a user making their choice. For instance, generate a random 256-bit value, and use those bits somehow to determine the outcome of the die roll. Before a user submits their guess, publish the hash of the value you used. Once the game is complete, publish the original value.
Feb
23
comment is encrypted body http secure
IV's should be rotated every time you encrypt data, not simply each "session".
Feb
20
comment Is “password knocking” a good idea?
Something like bcrypt is a far better way to slow down an attacker, as that also helps even if the attacker has your hashed passwords. Regardless, the latency of two extra requests to the server could be trivially simulated by calling sleep.
Feb
20
awarded  Nice Answer
Feb
20
comment Is “password knocking” a good idea?
To be more clear, if you consider typing this password in, your effective password is literally 123<Enter>456<Enter>789. You could argue that an attacker wouldn't know to hit enter at those precise locations, but that argument could be made for any character that could be typed there. This would be no different than if your password was instead 123|456|789. Ask yourself, when considering the literal act of sitting at a keyboard and typing in this password, what somehow grants the Enter key additional security over the | key.
Feb
20
comment Is “password knocking” a good idea?
But that is precisely mathematically equivalent to having those three passwords concatenated. If your "first" password is "123", your second password is "456", and your "third" password is "789", an attacker must spend the same amount of effort as if they were attempting to guess the single password "123456789". With the argument that they might not know that this is your scheme, that is true of the password itself; the attacker does not know that it's a nine-character password (or, equivalently, three three-character passwords). They must try all combinations until they find the right one.
Feb
20
comment Is “password knocking” a good idea?
@AviD I feel like this result must be patently obvious. Your password is literally now A <Submit> B <Submit> C. They are now simply concatenated by using the Return key.
Feb
20
comment Is “password knocking” a good idea?
@IsmaelMiguel You may continue to disagree all you like, but as members of the community have attempted to explain to you through several different approaches, the strength of the proposed scheme is virtually indistinguishable from concatenating the individual passwords.