# All Questions

284 views

### Best choice of finite field for AES on a 4-bit microcontroller?

As the finite field of $GF(2^8)$ are isomorphic to $GF((2^4)^2)$, $GF((2^2)^4)$ and $GF(((2^2)^2)^2)$, which of the fields is best suited and most efficient for 4-bit MCU and why? Would it be ...
97 views

### Is there any serious discussion about using blinding intermediaries in digital currency scenarios?

A digital currency system like Lucre (OpenTransaction) creates a coin by a mint blind signing the output of a hash function, which the payer then unblinds and pairs with the input to the has function. ...
299 views

### How is the MJH double-block-length hash function constructed?

I'm looking for information on the MJH double-block-length hash function, but the best free source I could find is the diagram on page 18 of Efficient hashing using the AES Instruction Set (submitted ...
147 views

### Can machine learning analyze random number generator?

I'm studying for random number generators(RNG) and I saw about machine learning a few days ago. So I searched analysis of RNG using machine learning. But I couldn't find such fields. Are there such ...
186 views

### Factoring two RSA modulus with known $|p_1 - p_2| < \ell$

I have two 1024bit RSA modulus $N_1 = p_1q_1$ and $N_2 = p_2q_2$ such that $0 <|p_1 - p_2| < \ell$, and $\ell$ is at most 64bit integer. Can I factorise $N_1$ and $N_2$? What's the answer when ...
129 views

### What cryptography is suitable to motivate High School students to learn math?

A High School math teacher in the Bronx asked me if I knew of any way to use cryptography in a way that motivates students (15 to 18 years old) to learn math. I do know that many of them want to ...
111 views

### How did the power measurements translate to AES Key?

A side channel attack is described here. I did not quite get , how the power measurements are used to get the decryption key , can any body explain it?
259 views

### reducing false positives in searchable encryption

Practical techniques for searchable encryption proposed by Song et al. [1] have a false positive rate of $l/2^m$ where $l$ is left half of encrypted bits and $m$ is right half and $l+m=n$ where $n$ is ...
92 views

### OCB and GCM security

Is OCB as secure as GCM or CCM ? Since OCB design is quite different from GCM and CCM, I was wondering if the security properties of these latters are satisfied by OCB, as well. Thank you.
137 views

### Key Derivation from random salted seed, HMAC and HMAC based KDF

I would like to generate a key which would be good enough to be used for encryption with AES in a mobile environment. My idea is to use as a seed ''random attributes'' from a mobile device. Is hashing ...
150 views

### Allowing multiple password reset tokens, and a question on random number predictability

I have a few requirements for a password reset system, along with some questions at the end as to its security. Requirements The aim is to provide a password reset mechanism satisfying the following ...
123 views

### Deterministic Rand function for Winternitz One Time Signatures

Suppose you are implementing a Generalized Merkle Signature Scheme, using the Winternitz One-Time Signature Scheme for the node signatures. Furthermore, suppose the implementation is to be stateless ...
91 views

### Length-preserving all-or-nothing transform

Is there any known way to construct a length-preserving all-or-nothing transform? In other words, a secure all-or-nothing transform where the length of the output is the same as the length of the ...
190 views

### Why does a perfect secrecy can be achieved when decryption correctness is not totally required?

By Shanon theorem, a perfect secrecy encryption scheme must use a key space of equal size as the message space. But when the correctness requirement is weakened such that $Pr[Dec_k(Enc_k(m))=m]=1/2$ ...
313 views

### Computing IV for CBC from PBKDF2 + HKDF

Note that this question is somewhat similar to Can I use my random IV (for AES) as a salt for PBKDF2? My current encryption format computes two random PBKDF2 salts (encryption and HMAC, 8 bytes each) ...
182 views

### How does a backdoor in the RNG enable an attacker to break encryption protocols?

I'm wondering how a backdoor in a random-number generator (as rumored the NSA have placed), actually compromises the security of things like VPNs or TSL/SSL. What I understand is that, if such a ...
98 views

### Are IVs and salts the same and usable for each other uses?

I'm new in the crypto world and I've just discovered PBKDF (I used to use typed passeword as symmetric key). When using some crypto mode, you're required to ...
143 views

### How can one calculate the estimated RSA key life based on Moore's law?

How can someone estimate the number of years needed to factor an RSA key based on the advancement of technology if followed Moore's law?
146 views