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2d
comment Why is OCB-AES mode not becoming a standard for authenticated encryption?
@figlesquidge It's available for some specific uses under a license that, among other things, prohibits military use. It also prohibits all kinds of other uses, for example commercial use in embedded systems. It's called the "non-military use" license for convenience, to identify that particular license by one of its key restrictions, not because it permits all non-military uses.
2d
comment Why is OCB-AES mode not becoming a standard for authenticated encryption?
The non-military license is actually three licenses, none of which permit, for example, commercial use in embedded systems. That the use is non-military is just one of the requirements that license has.
Apr
4
comment Why does the FBI ask Apple for help to decrypt an iPhone?
@DmitryRubanovich I don't understand the distinction you are making between "stored internally" and "stored on the chip".
Apr
4
comment Why does the FBI ask Apple for help to decrypt an iPhone?
@DmitryRubanovich You say "if the key is only stored on the chip", but the question specifically assumes that any hardcoded data stored on chips can be read.
Feb
19
comment Why does the FBI ask Apple for help to decrypt an iPhone?
@DmitryRubanovich You don't run it on the chip, you run it on an emulator. Did you read the question? It says, "including any hardcoded data that may be encoded in chips or whatever".
Feb
18
comment Why does the FBI ask Apple for help to decrypt an iPhone?
This is all interesting, but it doesn't seem to answer the question actually asked. The question says, "(including any hardcoded data that may be encoded in chips or whatever)". With this assumption, they can try all the class keys without help from Apple. And you don't refute the assumption.
Aug
28
comment Is there a hash function which has no collisions?
@supercat All you've shown is that the OP is probably making the same mistake you are, believing that it's better to make things impossible than impractical. For practical purposes, which is all that matters, there is no difference. Bijections have huge practical disadvantages and no practical advantages.
Aug
27
comment Is there a hash function which has no collisions?
@supercat That's just not a valid argument. Impossibility is, for practical purposes, indistinguishable from sufficiently impractical. For example, it's trivial to prove that public key cryptosystems cannot possibly make decryption by an attacker impossible (by trial encryption, for example), but such schemes are entirely practical. If you insisted an alarm system make burglary impossible, you'd use no alarm system at all, and that's foolish. You just need to make it impractical.
Feb
4
comment Signing the hash of a key with the same key
Would people really use a signature scheme were signing a piece of public information could compromise your signing key? Wouldn't that be an obvious catastrophic deficiency?
Sep
3
comment Elliptic Curve Cryptography Encryption Results
RSA does not involve any randomness, but it is trivially breakable (if used in the context involved here). Say I send you a message in plaintext, "Should we attack? Respond 'yes' or 'no' encrypting with RSA." This is trivially breakable, you can just trial encrypt both the 'yes' and the 'no'. This is one of the reasons RSA is not used alone. A public key algorithm that operates on short plaintext (which is what we're talking about here) must involve some randomness or it's trivially breakable by trial encryption.
Aug
28
comment Should I delete cryptographic data from memory?
What are you trying to prevent exactly? Presumably an "attacker" who had access to the machine's memory would thereby be entitled to the data the machine had processed. And if your model is that an attacker may have control over the machine while it's processing the data, erasing it later won't help. Are you trying to protect against sensitive data in swap or core dumps?
Jul
4
comment Cryptographic Challenge: How to Say Something Confidentially to Snowden?
You must have some way, in principle, to identify Snowden. If you have such a way, we must know what it is. If you do not, then it is provably impossible -- anything that identifies the Snowden you have in mind could also identify someone else.
Jun
21
comment Is there a hash function which has no collisions?
@improv32: Just use any encryption scheme you like with a key much shorter than the data. (You can easily remove this requirement if needed.) To later prove you had the data earlier, release the key you encrypted it with.
Apr
27
comment How can a key pair be derived from an arbitrary hash?
Yes, it basically is.
Apr
27
comment Is it possible to determine a PGP public key from encrypted data?
The decrypted content is of no help accomplishing this task. But he can trivially do it because the PGP file contains the ID of the key needed to decrypt it.
Apr
14
comment How to use salt if I am sending hashed password?
Step 3 is essential, do not skip it.
Apr
3
comment Is there a practical security difference between XXX-bit encryption?
This is not quite true. Consider, for example, if the process of generating the secret key from the password is extraordinarily computation intensive. If it's, say, a billion times harder to test if a guess at the password is correct than it is to check if a guessed secret key is correct, that can effectively make the password 30 bits longer relative to the secret key.
Apr
1
comment Decrypt digital signature using RSA public key with openssl
How many bits is the RSA key you are using? "data greater than mod len" usually indicates either a "toy" key that doesn't have enough bits or an attempt to operate on the actual data where you should be operating on a hash.
Mar
26
comment which asymmetric cipher provide highest performance?
Are you talking about bulk encryption/decryption of large amounts of data? Or are you talking about large *numbers) of encryption/decryption operations of small amounts of data? (If the former, I think you don't understand how asymmetric ciphers are used.)
Mar
22
comment Even passwords are vulnerable to hash collision attacks?
For 6 or 7 character passwords, there's no point in worrying about hash collisions. Just guessing the password would be much easier.