Linked Questions

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1answer
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 ...
1
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1answer
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 ...
2
votes
1answer
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 ...
1
vote
1answer
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 ...
2
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2answers
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'...
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3answers
195 views

Factoring Anderson's RSA backdoor

In 1993, Anderson [1] 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 ...
21
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1answer
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 ...
2
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2answers
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 ...
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2answers
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 ...
7
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1answer
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 ...
0
votes
1answer
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 ...
44
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4answers
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: ...
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1answer
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 ...
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0answers
56 views

Will a list of all prime numbers upto certain number of bits compromise crytopgraphic algorithms based on prime factorization? [duplicate]

I understand that many cryptographic algorithms depend on the difficulty of large prime factorization. Will a list of all prime numbers upto certain number of bits make it easy for an attacker to ...
1
vote
1answer
82 views

Which RSA keys are actually attacked In practice?

I understand that it is important to check how hard it is to attack RSA keys, but I assume at some key size attackers would not even try. Real attacks are carried out by exploiting mistakes in the ...

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