# All Questions

15k views

### What is Attribute Based Encryption?

Can someone explain what attribute based encryption is? I was searching for a book or something that can help me in this regard but so far I have found none. Google also returns practically nothing ...
21 views

### CRL number generation sequence

RFC 5280 states that the CRL number should be monotonically increase. I have seen this common practice of incrementing the CRL number by 1, everytime a new CRL is generated. But can i use epoch time ...
77 views

### Are developers expected to implement Diffie-Hellman key exchange themselves?

I noticed that the GO standard library has some really nice functions for performing AES encryption / decryption in various modes. However, I couldn't (yet) find anything for Diffie-Hellman key ...
783 views

### Stopping timing attacks on AES: Why is it important to prevent the OS from interrupting the AES computation?

I read the paper Cache-timing attacks on AES (by Daniel J. Bernstein), but I don't seem to understand everything. The author dedicates a long section on how to prevent the OS to interrupt an AES ...
35 views

### Is it okay to use a variable-time RSA implementation to verify TLS certificates?

RSA as implemented by OpenSSL et al. needs to protect against side channel attacks, at a big performance penalty. However, TLS certificate validation involves no secrets. Therefore, I should be able ...
92 views

### How does a company like Apple keep its keys safe? [closed]

Whatever key is used to sign new iOS updates (for example) must be incredibly well-protected. How does a huge corporation like Apple keep those 4096 bits safe?! Same goes for SSL keys for websites ...
56 views

73 views

### How common are weak RSA keys?

There exist certain attacks that can be used against RSA keys whose prime factors are of specific forms, such as one by Coppersmith. How common are these RSA keys? If you generate primes randomly, ...
69 views

### how to verify subset of hashes from hash list

I need to verify a couple hashed (SHA256) integers from a list of approximately 50 hashed integers in a message. The list can be divided into groups. The (plain) integer data is not in the message, ...