7k views

### Is it easy to crack a hashed phone number?

I want to SHA256 hash phone numbers in order to hide them. Is this a good idea? Are there any other ways I could make this safe?
1k views

### Representing a function as FHE circuit

I am actually trying to study homomorphic encryption (on lattices) but I'm facing a problem. Every paper that I have read so far talk about writing the function to evaluate on ciphertexts as a circuit,...
738 views

### Can ECB mode really leak some characters?

In an Ars Technica article about Adobe's use of 3DES in ECB mode, there's a paragraph The passwords, according to password expert Steve "Sc00bz" Thomas, are encrypted in a mode known as ECB. That ...
378 views

### OpenSSL not producing messages of expected size

I have a 16 byte file, and after encrypting it, its size weirdly changes. ...
441 views

### What will be appropriate AES padding characters?

I am completely noob in terms of cryptography and security. So I decided AES Cipher for encrypting my data. I pad my input data String with blank white spaces to fit it in multiples of my cipher ...
368 views

### Frequency Analysis on DES, AES, 3DES using Cryptool2

I am trying to analyze symmetric block ciphers like DES, 3DES and AES, using Cryptool 2. I want to do a frequency analysis on each of these ciphers, in order to comment whether this is an effective ...
334 views

### Secure hashing when the input comes from a small space

I have a problem that I'll simplify here. Let's say I want to store a table of {person, fav color}. Only, I don't want anyone to ever be able to look up a person't favorite color; the only thing ...
164 views

### Protect the original message of a hash from brute force

My apologies for the somewhat inaccurate terminology. Basically I have some simple messages (entropy ~50 bits) the user will use for registration. The messages should remain private, and I don't ...
130 views

### Character frequency graph for cipher text

I have studied about the mono-alphabetic substitution cipher. With Character frequency graph, the encrypted text can be decoded. I am wondering how can be happen?
87 views

### Combining CTR and ECB modes to prevent attacks

In Reusing AES-CTR Keys and IVs for File Encryption, the OP was asking about a composite encryption scheme $$C_i = E_K\left(P_i \oplus E_K\left(IV + i\right)\right)$$ which is basically just a CTR ...
107 views

### Using same key and nonce for different field of the same document

I have some fields, similar to NAME, SURNAME, EMAIL, ADDRESS... I'm using NaCl for symmetric encryption. Is bad If I Encrypt every field with the same key and nonce? They are encrypted and stored ...
121 views

### Frequency Attacks on Encrypted Database

I'm trying to build an encrypted database where we can't trust on the database manager. And since encrypt data in a deterministic way is bad, attackers can recover information doing frequency attacks, ...
72 views

### What exactly is the problem with using electronic codebooks as a block cipher mode [duplicate]

I was wondering why it is a problem with using ECB as a block cipher mode