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Nov
13
revised Is there a proof for showing any cryptogram is crackable?
added 1 characters in body
Nov
13
answered Is there a proof for showing any cryptogram is crackable?
Nov
12
reviewed Approve What is wrong with AES-CTR-HMAC-SHA256 - or why is it not in TLS?
Nov
12
reviewed Edit Explicit Key SHA-1
Nov
12
revised Explicit Key SHA-1
some minor spelling/formatting. Second question isn't clear english, but didn't understand well enough to correct
Nov
12
reviewed Approve Ideal system for an encryption scheme
Nov
12
reviewed Approve Can you explain partial private key extract algorithm in certificateless Public key cryptography?
Nov
12
comment MD5 theoretical question
There is a difference between collisions existing and actually being able to find them.
Nov
11
comment Are there public $p$ and $q$ numbers for use in DSA?
NIST has published a bunch of them.
Nov
10
answered Can two people with different one time pads securely exchange a message like this?
Nov
10
comment Can two people with different one time pads securely exchange a message like this?
The general scheme is called Three-pass protocol and it's secure for some commutative ciphers, but simple xor is not one of them.
Nov
10
comment Can two people with different one time pads securely exchange a message like this?
An attacker who sees all the messages can trivially extract the plaintext with a bit of xor-ing.
Nov
10
comment Is it true for Java that the transformation mode and padding is ignored when using RSA?
It's even harder since PKCS#1v1.5 encryption padding is broken in a way that requires the higher level protocol to carefully work around its weaknesses. If you use RSA by yourself, use OAEP padding, not v1.5.
Nov
10
comment How can two (or more) parties share and agree upon a common random seed?
@rath Without collision resistance a cheater can pick which of them to reveal and the commitment becomes non binding. So collision resistance if an essential part of the protocol.
Nov
10
comment How can two (or more) parties share and agree upon a common random seed?
Since collision resistance is required, the security level of 64 bits provided by a 128 bit hash is insufficient.
Nov
10
comment Why don't we use MACs to store passwords?
For smaller websites a HSM is too annoying to deploy. But I'd expect big websites like google to encrypt their password hashes with HSMs.
Nov
10
reviewed Approve Can Diffie-Hellman generate values in a specified range?
Nov
10
comment Can Diffie-Hellman generate values in a specified range?
btw. DH never returns 0 if both sides follow the protocol. Only way to obtain 0 is if one side uses 0 as public key $A$, which is obviously broken and doesn't result from computing $A=g^a$ for any private key $a$.
Nov
10
reviewed Approve Can Diffie-Hellman generate values in a specified range?
Nov
10
reviewed Approve No Birthday Attack to TCR