52 views

### Is digital signature without schema possible?

In my application I want to use Rabin crypto system with short keys (like 128 bits) and MD5 for hashing. I found that schema like PKCS1-V1_5 or PPS does not allow you to have such small keys and ...
82 views

### Can we sign and encrypt with RSA keys of both sender and receiver?

By using RSA encryption, it is possible to "encrypt" sign with sender's private key and then with receiver's public key, and decrypt with receiver's private key and then with sender's public ...
104 views

### How to factorize the group order in Pohlig-Hellman algorithm

The Pohlig-Hellman algorithm is for computing discrete logarithms in a group whose order is a smooth integer. This algorithm requires the factorization of the group order. However we know that ...
36 views

### Paillier estimate attack costs on short keys

I was thinking about how to use the homeomorphic property of that cryptosystem to achieve not a "semantic security" but a less ambitous obfuscation of the source code (an ipotetical scenario ...
1k views

### Prime factorization of 700 decimal digits number

I'm a newbie to encryption. If I create a number 'n' as a product of two prime numbers 'p' and 'q' with the following specifications: 'p' is a fully random prime with 300 decimal digits in length. 'q'...
195 views

### Factoring Anderson's RSA backdoor

In 1993, Anderson  proposed a backdoor to the RSA key generation algorithm. This backdoor requires that a backdoor key (prime) $A$ be implanted within the key generation portion of the RSA ...
9k views

### What is the history of recommended RSA key sizes?

One can find up to date recommended key sizes for RSA at NIST sp800-131A for example. In short, it suggests a key size of at least 2048 bits. Is it possible to find a history of recommended key sizes ...
195 views

### Actual RSA encryption & decryption of strings?

$K_{pub} = (n, e)$ $K_{pvt} = d$ Then $E_{K_{pub}}(x) \equiv x^e \mod n$ Practically, when RSA is used to encrypt strings, what is the $x$ here? You cannot take it byte by byte because $\mod n$ will ...
134 views

### Is an efficient integer factorisation algorithm a threat to security anymore?

Nowadays, private key systems like AES have replaced RSA. Even for digital signatures, people mostly use ECC, so even if an efficient integer factorization algorithm is made, would it be a threat to ...
9k views

### Should I use RSA encryption since RSA is said to be broken by NSA?

I am developing a simple web app that uses asymmetric encryption, but I am not sure whether to chose RSA for the reasons mentioned above. What are your suggestions? Also if I decided to go with RSA ...
71 views

### What would be the most recommended AES && RSA Keys for production?

While I am a front-end developer and not a security expert programmer, I am worry about the keys I am using for my AES && RSA encryption. Please help me to understand: Is the following keys ...
27k views

### Security strength of RSA in relation with the modulus size

NIST SP 800-57 §5.6.1 p.62–64 specifies a correspondence between RSA modulus size $n$ and expected security strength $s$ in bits: ...
78 views

### Choosing a suitable prime for accumulators

I am trying to work out accumulators and generate $S = \{ e_1,e_2 \ldots, e_n \}$ from this (Section 3.4 - Choosing a Suitable Prime). For each element of $e_i$ compute its representation $x_i$.(This ...