Implementing a cipher or protocol is the process of taking it from its mathematical or algorithmic description and producing a working version, often in computer software or hardware. This tag should be used for any question discussing the various potential considerations and pitfalls of this ...
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Storing counter value of HOTP at client side [closed]
How can we store counter value on the client side in HOTP??
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2answers
95 views
How to compare two datasets „anonymously”?
Ok, I hope this question makes some sense because I am not so sure how to word it any differently… Imagine the following situation:
There are 10 defined colors (blue, orange, yellow etc.)
There are ...
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122 views
Calculating PGP Symmetrically Encrypted Packet data
I have been trying to create a properly encrypted data packet using the format described in RFC 4880. However, I have been unable to verify any of my outputs due to the lack of examples to draw from ...
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1answer
72 views
In ECDSA, how many field operations are used for signature verification?
I am wondering about the computational cost of ECDSA signature verification, in term of multiplications in the base field; and, as an aside, in term of (much cheaper) additions. To make things ...
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1answer
56 views
Linkable ring signature scheme
I need an implementation of linkable ring signature, a ring signature which allows identifying whether two signatures belong to the same signer. It has important privacy-related applications, like ...
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31 views
Hardware implementation of pairing
I would like to design a hardware-based accelerator for a pairing algorithm to make it faster. I know that I need to do arithmetic over a base and an extension field.
Could anyone would suggest which ...
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2answers
209 views
Why is SRP not widely used?
SRP seems to be a very good password authentication protocol, compared to any other things used now. So why is there no popular implementations, or even no working secure implementations?
I tried to ...
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1answer
110 views
Polynomial multiplication and division in 2^128
I want to multiply and divide polynomials, and implement the extended Euclidean
algorithm for polynomial greatest common divisors, over a Galois Field of size $2^{128}$. Moreover, I want to use the ...
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1answer
63 views
Encrypting a broadcast channel
We're building a data service that is expected to go out through a single "fat pipe" channel. The design requirement says that the data in the channel must be protected by authentication and ...
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2answers
243 views
Custom crypto library in C
I will be making (in the near future) an app that will contain some pretty heavy crypto. As it is possible that my app will be ported to different devices (initially it will be iOs only, but Mac, ...
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3answers
203 views
Implementing secret reconstruction in Shamir's Secret Sharing
I am trying to implement Shamir's secret sharing in C++.
I have got the generation of shares working.
However, I am very confused with the reconstruction of shares. I get the part on how three users ...
4
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3answers
233 views
McEliece Cryptosystem Implementations
Are there any current implementations (language irrelevant) of the McEliece Cryptosystem?
I have been hunting around all day, and yet, have only found a few mathematical equations pertaining to the ...
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2answers
185 views
Signature schemes for underpowered devices (8bit microcontroller)
I am currently researching into a small scale home automation system, aiming for cost. The system architecture is basically one master and several slaves which are connected in parallel.
Recently ...
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2answers
138 views
Zero-Knowledge Challenge-Responce Protocol
Good day to everyone.
I am trying to implement an e voting system (just for reference -it is not important though-it is described at the Internet Voting Protocol Based on Improved Implicit Security ...
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1answer
130 views
What should I be aware of when implementing algorithms myself?
I plan to build my own crypto library. The project will be primarily for me to learn (and if useful for no other purpose, that is fine). In the past I have implemented a few hashes, and AES quite a ...
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5answers
482 views
Software implementation of a commutative cipher?
I've got an application (detailed below) that calls for the use of a cipher that is commutative. I've been doing some googling & reading, and there are two algorithms that seem to get mentioned ...
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1answer
86 views
Trapdoor implementation
Please refer to this secure index paper. On page#6, a trapdoor is defined as
...
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39 views
Security of .net AES implementation and security of a hash MAC
Hello I wanted to ask if there is any review about the security of the AES implementation of the .net Framework?
I found nothing concrete to that question, searching the Internet.
And, but this is a ...
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2answers
327 views
Is this a correctly formatted PGP session key packet?
RFC 4880 may be full of information, but it can be incredibly vague at times, so im looking for someone who actually knows the answer to this.
Given this public key:
...
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0answers
35 views
How to create a public-key certificate for RSA Web of trust?
How to create a public-key certificate for RSA Web of trust?
I have (for exemple) two public / private key pair (obviously).
They all need to sign each other certificate.
How to create the ...
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1answer
59 views
What is the most secure way to let Alice “input” her private key, transfer it to the server and decrypt the message?
What is the most secure way to let Alice "input" her private key, transfer it to the server and decrypt the message? (Then destroy the private key on the server)
Every connection is using SSL.
...
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2answers
336 views
Where i can find an AES implementation in python?
Where i can find a "reviewed" version of AES implementation in python. Not an API like PyCrypto whereby you can call AES algorithms in a single line.
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1answer
146 views
What does modular inversion mean?
I'm trying to implement an e-voting algorithm, which is described at the paper "Internet Voting Protocol Based on Improved Implicit Security" by Abhishek Parakh & Subhash Kak.
At the Example 1 ...
4
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1answer
83 views
Two way encryption with random IV
I'm attempting to encrypt some information into our database to be later pulled back out and displayed to the user. Searching and reading up on different methods I found a post over at stack exchanged ...
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1answer
255 views
On-the-fly computation of AES Round Keys for decryption?
The usual implementation of AES first computes all the Round Keys sequentially starting from the key, and stores them in RAM for later uses. However, when enciphering a single block with a key that ...
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1answer
199 views
Are there any Implementations of Secure Indexes?
There are several papers about Secure Indexes, for Example "Searchable Symmetric Encryption:
Improved Definitions and Efficient Constructions" and "Secure Indexes". ...
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2answers
115 views
What cipher mode is suitable for independantly decryptable short messages?
I'm building a small VoIP client which transmits encrypted audio data via UDP, and some packet loss is expected, so each packet will need to be decrypted separately even if others in the stream don't ...
3
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2answers
381 views
Implementing AES in C++: 4x4 Array of unint8_t, or 4x1 array of uint32_t?
I'm implementing AES in C++, and, inspired by the way words are handled in SHA, I decided this time to handle the state as a one dimensional array of 4byte unsigned integers as opposed to a two ...
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2answers
311 views
How does one calculate the cryptoperiod?
NIST Special Publication 800-57 defines a cryptoperiod as
the time span during which a specific key is authorized for use by legitimate entities, or the keys for a given system will remain in ...
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1answer
166 views
How does the energy consumption of the SHA-3 finalists compare?
I am curious, is there any paper where SHA-3 competitors are compared in terms of energy efficient?
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1answer
346 views
How can I implement the “Multiplication Modulo” and “Addition Modulo” operations in IDEA?
I am currently working on IDEA (International Data Encryption Algorithm), and I don't know how to perform Multiplication Modulo and Addition Modulo.
This is how IDEA operates:
IDEA operates on ...
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3answers
228 views
How to avoid a chicken and egg scenario with encrypting passwords?
I am working on application that allows users to upload files containing company data and then share those files with a list of other users that have specific roles within the system.
I want to ...
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1answer
162 views
RSA 1024bit decryption performance
i want to know how many RSA 1024 bit long key decryption can a regular pentium4 computer do per second ? how to calculate RSA performance and determine its remaining time ?
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1answer
191 views
Recommended Books for Cryptography : Theory and Implementation [closed]
It is a great idea if experts in Cryptography from mathematicians to security engineers introduce books and textbooks which they think is helpful or instructive for all people interested in the ...
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2answers
179 views
Cryptographic GUID?
I need a GUID. Really just any number that is likely to be unique. However I prefer not to leak time and other things as a GUID may leak. What should i use as a cryptographic replacement? I was ...
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1answer
121 views
Why does .NET's ECB mode implementation append a constant block to my ciphertext?
Consider the following code and output:
...
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243 views
Matlab vs mathematica vs python [closed]
I just want to know that which is better for cryptography implementation ie in dealing with huge numbers.
4
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1answer
218 views
Why x00 is usually avoided in salt?
In .NET Framework, there is a cryptographic Random Number Generator (RNG) provider which enables to generate a cryptographically strong sequence of random bytes. This provider contain, among others, ...
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3answers
75 views
MISTY1 Implementation error
I am trying to implement MISTY1. It's RFC, RFC2994, contains psuedocode that I basically copy and pasted into Code::Blocks. However, I managed to mess that up somehow. After 2 days, I still have not ...
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0answers
79 views
How to properly format a PGP Message Block?
As sort of a follow up to my (currently) unanswered question, if it is correct, how do i properly calculate and format the packet that actually stores the data being encrypted? I thought I knew what I ...
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2answers
234 views
Additive ElGamal cryptosystem using a finite field
I'm trying to implement a modified version of the ElGamal cryptosystem as specified by Cramer et al. in "A secure and optimally efficient multi-authority election scheme", which possesses additive ...
2
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1answer
308 views
Is there a standard for OpenSSL-interoperable AES encryption?
Many AES-encrypted things (files, strings, database entries, etc.) start with "Salted__" ("U2FsdGVkX1" in base64).
I hear it's some sort of OpenSSL interoperability thing a b c.
Is there some ...
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1answer
427 views
Format-preserving encryption implementations
I'm looking for a general, free implementation of Format-preserving encryption
as described in this article and on wikipedia.
Possibly in a well established cryptography toolkit.
My intention is to ...
4
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1answer
191 views
Length of data to hash for PGP
I have finally managed to verify some simple PGP signed message blocks. However, I discovered that for some reason, my implementation limits me to verifying data that is 9-16 bytes long. no less. no ...
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1answer
401 views
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3answers
286 views
Order of cascaded ciphers
Does the order of a block cipher cascade (e.g. in TrueCrypt) make a difference to the security provided, assuming independant keys?
For example:
...
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0answers
155 views
Proper formatting of symmetric algorithm secret key
Given this description from RFC 4880 sec 5.1:
The value "m" in the above formulas is derived from the session key as
follows. First, the session key is prefixed with a one-octet algorithm
...
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0answers
94 views
Setting protocol parameters to achieve concrete security
Background
One issue with modern security proofs is that they are usually asymptotic. In other words, such proofs are usually formulated as follows: For any polynomial-time adversary $\mathcal A$, we ...
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3answers
326 views
Learnt cryptography and python. What do I do next? [closed]
OK, so I have spent the last 3 months learning cryptography through the Coursera-Stanford crypto course. I also learnt Python thoroughly.
Now I am eager to use this new-found knowledge. But neither ...
1
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3answers
213 views
Getting started [closed]
I'm looking for a good place to start in cryptography and places to go to get free books etc on the topic.
I have been looking online but I always get stuck at some point or another. I need something ...
