# All Questions

380 views

### How can I control the output of a hash function to output to specific data according to similarity?

I do not know if the question lies exactly in that field but I'll give it a try unless rejection. I want to study methods of applying LSH functions to feet in a specific area of digest values. ...
37 views

I was thinking of using different and independent password for different websites, but not storing them in some password manager so I don't need to backup the passwords. I thought I could use some ...
52 views

### substitution Box(s-box) for AES

can anyone suggest me any fast searching method or algorithm to find best S-Box among a big number of S-boxes?for example ; if i have 100 different s-boxes. i want to pick any one which is secured ...
23 views

### Why am I getting a wrong output when implementing Feige-Fiat-Shamir ID protocol?

I am trying to implement the Feige-Fiat-Shamir identification protocol. I've read another posting here on this site and I tried to adapt - however the end results always fail to match. Maybe because ...
37 views

74 views

### A simple client/server authentication protocol

Some days ago I asked for a help to find and correct the problems of an authentication protocol. I closed the post because I was convinced I can correct it but, unfortunately I'm having some troubles. ...
55 views

### Calculate if a digital signature is valid

In the book An Introduction to Mathematical Cryptography, it mentions a section on digital signatures and a theoretical example. I am having difficulty understanding the book and I was wondering if ...
105 views

### Will the contents of a password protected Zip 2.0 file be safe for a week

I will need to distribute a file to people for a challenge and I need them to open the file at the same time. The file will be provided a couple of days before the challenge. For maximum compatibility ...
87 views

### Is it safe to use the same IV for multiple encryptions in AES CBC mode when you are always encrypting random bytes?

I am generating random bytes (16 or 32 bytes at a time), and I want to encrypt them using a 128 bit AES key in CBC mode. Am I really weakening this horribly if I am reusing the same IV and key each ...
159 views

### Use Smart Card to decrypt files

So I'm trying to figure out the feasibility of using a Smart Card to decrypt files in an offline scenario. I wish to sync encrypted files to a mobile phone with a Smart Card reader case. The files ...
131 views

### How to identify the difference between two cryptographic schemes in terms of security?

I am currently working on a project, that requires using encryption libraries namely (LibScarab and FHEW). I want to know how can I compare the two schemes in terms of security (I already compared ...
129 views

### Detecting encryption in real-time?

Is there anyway to detect encryption in real-time through a common signature or pattern recognition. Say, a file is being encrypted using an AES-256 cipher, if I have access to the file stream - can ...
32 views

### Is there an avalanche effect using block cipher modes of operation?

I am studying cryptography and various block cipher modes of operation. Suppose I changed one bit in the last block of the message. Wouldn't that imply no change in all encrypted blocks except for ...
101 views

### Given the first half of a SHA-1 hash, can you predict the second half?

I know this applies to secure ciphers, but does this also apply to hashes?
50 views

### Why does Apple create a certificate for my push notification key [closed]

Brief rundown of how Apple Push Notifications (APN) work: Generate a keypair, generate a CSR for it Upload the latter to your Apple Developer account and associate it with your mobile app In the ...
61 views

### Testing implementation of cryptography algorithms: Brainstorm

I wonder what kind of techniques can be used to validate implementation of cryptography algorithms? The obvious one is to run specific algorithms against publically known test vectors (i.e. from ...
101 views