# All Questions

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### Attacking Scrypt Under Access Pattern Leakage

Could cache-timing channels (such as exist for certain block ciphers) somehow be made use of in order to extract memory-access pattern information if both the attacker and user are NOT in a shared ...
50 views

### How to use modes of operation in DES? [on hold]

How to use modes of operation in block cipher with Data Encryption Standard (DES) ? How the Feistel structure properties are achieved in DES when a mode of operation such as ECB is used?
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### Ideal way to profile/performance-measure cipher implementations

I have implemented a bit-sliced version of two ciphers (Gibbon-120 and Hanuman-120, both part of the Primates family of ciphers: http://primates.ae/wp-content/uploads/primatesv1.02.pdf ) I now want ...
75 views

### Initializing PGP keys by one side

I am using a PGP method to encrypt and decrypt messages shared between users A and B. Upon the start of a message exchange is the initialization of the public and secret keys by both Users. Lets say ...
36 views

### How do I decipher a text using a repeating one-time pad?

I have an encrypted message that is 582 characters long. I know that: It is in hexadecimal It has been encrypted using a one time pad The pad's length is exactly 50 characters When the pad reaches ...
29 views

### Do RSA keys contain a checksum mechanism? [duplicate]

I'm new to cryptography, and I was making an experiment a few minutes ago, but I want to have some deeper knowledge about RSA public and private keys. I have a set of keys One begins with ...
39 views

### Efficiency of oblivious algorithms vs non-oblivious algorithms

Recently, plenty of researchers are looking at designing efficient data-oblivious algorithms. Roughly speaking, an algorithm is said to be data-oblivious if its data access patterns are independednt ...
36 views

### Are any of the practical implementations of ORAM being used in a real world system?

The concept of Oblivious RAM (ORAM) was first introduced by Oded Goldreich and Rafail Ostrovsky in 1996. However, in the past 5-10 years there has been a surge in the amount of research that looks ...
53 views

### How to deniably send a value

Alice has a single bit of information, b, that she wants to send to Bob (over an unalterable but possibly-monitored channel) but in such a way that without the ...
22 views

### Does changing an encryption key make an application unusable [on hold]

I have a small piece of basic PHP code that adds new users to a database. It was working fine yesterday but this morning I read something about encryption and realized I hadn't changed the encryption ...
181 views

### Perfect Forward Secrecy in MTI/A0

Would the property of perfect forward secrecy still be achieved in MTI/A0 for a session key that was established between C and D when one LL-key aD is revealed so that both LL-keys aC and aD are ...
78 views

### Finding all polynomials up to a given degree to generate a bit sequence

Consider the following bit sequence: 00100000110 Using Berlekamp-Massey algorithm we can find the following minimal degree polynomial: $P(x)=x^6 + x^5 + x^4 + 1$ Now, is there a way to find all ...
61 views

### What makes an open source encryption algorithm safe?

Take for example the popular AES algorithm where we have a combination of substitution, shift row, mix column, and add key steps involved in encrypting plain test. All of the mathematical operations ...
3k views

### Signal vs Telegram in terms of protocols?

Some time ago, the question was asked in chat, why MTProto (Telegram's protocol) is supposedly worse than Axolotl (Signal's protocol) as both protocols have been the inventions of their respective ...
67 views

### Who invented the $1^n$ notation? [duplicate]

I am always wondering about the seemingly odd syntax $1^n$ which designates the security strength of a cryptographic algorithm. Who invented this (odd) syntax and what was the reason for inventing ...
64 views

### Parameterizing adversaries with security parameters

In many cryptographic games, the adversary doesn't seem to be parameterized by the security parameter.‡ Are such games equivalent to variants in which the adversary is parameterized by the security ...
48 views

### What is the non-programmable random oracle model?

I would like to know the difference between the random oracle model and the non-programmable random oracle model. ​ What is the difference?
384 views

### Are there key-derivation functions that are safe to use in parallel on the same secret?

I'm considering using a key-derivation scheme for generating multiple keys from the same user secret. It is important that given all but one of these derived keys, it is not feasible to calculate the ...
91 views

### Importance of round complexity in determining the efficiency of an MPC protocol

Literature has different ways of specifying complexity of an MPC protocol: computation complexity that measures the number of (assumed primitive) operations performed by all the parties; ...
16 views

### jpbc Element compare [on hold]

I want to compare an element of jpbc.Element produced with another element,produced later.If am inserting the first element to mysql db ,which datatype i will use for an element of type {x=...
137 views

### Any benefit to writing a message as a mix of 2 languages before encryption?

For example, imagine a message that is a mix of Japanese and English words; Japanese in unicode, English in ASCII. Japanese doesn't use spaces between words. The sentence structures, anything ...
80 views

### Is it possible to test implementation for side-channel attacks?

When it comes to implementing cryptographic algorithms, there seems to be a big focus on the difficulty of doing so without introducing the potential for side channel attacks and the knowledge ...
227 views
+100

### culling equivalent Enigma keys for short messages

The following for-loop iterates over all possible keys for an M3 Enigma for three selected rotors: ...
22 views

### How to decrypt the below encrypted messages? [on hold]

My friend was experimenting with the encryption methods (self-made) to encrypt text using ASCII map. He wanted to try this idea whether this encryption can be broken and so shared an encrypted text ...
17 views

53 views

### Explanation of cryptographic terminology for newbies [on hold]

I feel like I'm making a mountain out of a molehill here, but I have (what should be) a relatively simple project, but the terminology used all over the Internet is either too simple or too difficult ...
33 views

### Dependency of cryptographic protocols on cryptography primitives

To what extent depend cryptographic protocols on cryptographic primitives? Are there cryptographic protocols that can only be implemented with certain cryptographic primitives? If the answer is yes, ...
12 views

### Can someone help me decipher this? [on hold]

I have absolutely no idea what this is or how to decipher it. Could you either do it... or help me learn how to? ...
39 views

### Found weil pairing. Index Calculus method on the results of weil pairing

Consider Elliptic curve with p = 59, A = 1, B= 0, P = (25,30) and Q=(35,31). So I tried to solve this using MOV attack. The torsion point for them E[5] is R(-25,30i) where is sqroot -1 Chosen two ...
162 views

### System parameters in identity-based encryption

In IBE schemes, the system parameters are $(q, \mathbb{G}, F, \hat{e}, P, Q, T, H_1)$. I don't know $\hat{e}$. For example, in type A pairing… ...
502 views

### Test Vectors for ciphers

While implementing ciphers (/hash functions, ...), I often face this problem: Where to find test vectors for it; so that I can guarantee my program is correct. It is generally a tedious job to find ...
82 views

### ORAM over Third Party DB

Oblivious Ram (ORAM) is a cryptographic technique that is used for secure DB querying without leakage on the access patterns. There are several schemes for ORAM, amongst the most popular ones, there ...
946 views

### Can any MAC be used as a KDF?

First, let me clarify what I mean with a Key Derivation Function (KDF). I'm interested in KDFs that take an $n$-bit symmetric master key and some diversification data of arbitrary length as input and ...
63 views

### Is there a method/protocol to validate a self-signed certificate by comparing a shortened hash?

I'm working on a solution where an iPad should connect to a server software running on a laptop using TLS with a self-signed certificate that was automatically generated on the laptop during the ...
6k views

### In RSA, how does the CPU deal with this huge modulus (8192 bits)?

Whilst I understand how the RSA algorithm works, I don't understand how the CPU operates when it needs to use the mod function with a huge number $n$, for example. ...
52 views

### Why is RSA still being used? [duplicate]

In hybrid encrytion, I still see that some site's use RSA in their https connection, so now I wonder, why do they not use ECC instead of RSA, ECC requires less computational power and encrypt's and ...
532 views

### Decrypting a blowfish cipher with three keys

Disclaimer: I'm pretty new to cryptography and I don't have a strong mathematical background. I apologize in advance if I missed something blatantly obvious. I participated in a security CTF this ...
69 views

### Public-key Cryptography: I need a technical answer [closed]

So, I already understand the point of Public-key cryptography, and how it's supposed to work. I understand the basics, and I've seen way to many diagrams. What I haven't seen enough of, however, is ...
78 views

### tripartite diffie hellman with Weil pairing

I try to understand how the tripartite Diffie-Hellman key exchange works. I read Joux's paper for this: https://www.semanticscholar.org/paper/A-One-Round-Protocol-for-Tripartite-Diffie-Hellman-Joux/...
141 views

### Difference left-or-right CPA security, IND-CPA security

I am trying to understand the notion of left-or-right-CPA (LOR-CPA) security for private-key encryption schemes introduced in my lecture. If I understood it correctly so far, the only difference to ...
112 views

### Is the use of AES in LoRaWAN correct?

I'm reading about LoRaWAN (specification). This network protocol has a particular way to encrypt data, detailed in the part 4.3.3.1. Here is a recap of how the encryption work, as I understood it. ...
39 views

### Crypto lib that use files instead of passphrase [closed]

I would like to program an application to allow people to encrypt files without using a password or pass-phrase but an arbitrary long file. I'm searching for a library that allows me to safely create ...
48 views

### Binary format of encrypted PGP private key?

Short Version of the Question: I would like to remove any predictable information from an encrypted private keys binary representation. Does anyone have a hint where the binary format for encrypted ...
188 views

### Verifying Without Knowing Key

Say user Bob sends an encrypted message to a server. People can download the message from this server and later get the key directly from Bob. Is it possible for the server to somehow verify that ...
Can anyone help me with the following problem. Given a prime exponent $e$ and a prime number $n$, find $b$, where $b^e \equiv 1 \bmod n \land b > 1$. For example, $b^5 \equiv 1 \bmod 11$ how to ...
I found in all PAKE papers, the security is defined as something like this: Let $Succ(A)$ be the probability that an attacker $A$ successfully distinguished the session key from a random string. Then ...