# All Questions

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### Which cipher text is easiest to guess the plaintext?

I know that there are approximately 2^88 diff erent permutations of 26 characters. The stream cipher A5/1, which generates a binary keystream using three irregularly clocked LFSR, and has a 64-bit key....
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### Doubts regarding implementing AES128 bit algorithm in my IOT system

I want to implement AES128 in my IOT network which consists of a Master device which runs Linux on it and slave devices which are 8-bit microcontrollers that periodically transmit data packets to the ...
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### Capital passphrases with rainbow tables?

I'm currently trying to learn how rainbow tables work for a personal project of mine, but I am a little bit confused on how passphrases can be found. Here are the steps that seem do this, from the ...
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### How to implement this encryption related code in JavaScript? [migrated]

I have following code in Java. ...
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### Practical perfect security in bitwise XOR vs integer addition/subtraction cipher

XOR already provides perfect security in theory but it's hard to apply it in practice due to strict requirements. I was thinking about whether simple addition/subtraction in integer format would not ...
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### Cryptographically secure hash function vulnerable to length extension attacks both to front and to back?

Is there any hash function where both $\text{hash}(m\|k)$ and $\text{hash}(k\|m)$ are vulnerable to length extension, but $\text{hash}(m)$ is itself secure?
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### Time complexity of Weil pairing

I ran and timed an implementation of the Weil pairing on three set of parameters. One with an order of 512 bits, one with 256 bits and the last with 161 bits. I took the Miller's algorithm to compute ...
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### ECDH: create Public Key from x, y coordinates [on hold]

I have the x, y coordinates of a EC public key ( i have the bytes also ). I need to convert the x,y coordinates bytes into a ECPublicKey. ...
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### How to Securely Transmit Salt and IV vector

Hello I wanted to ask something about my scheme. As we know, salt is being used to prevent rainbow attacks. In my scheme, in order to let the receiver to decrypt some data,generated one time to be ...
35 views

### How many qbits are required to break Diffie-Hellman over a multiplicative group

There have been comparisons between RSA and ECDH with regards to the number of qbits (qubits) required to break the algorithm with a specific key size. But how many qbits are required to break "...
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### Multilinear trapdoor commitments secure against concurrent man-in-the-middle attacks

I am trying to understand how to apply a multi-trapdoor commitments described by Gennaro and what makes them secure against a concurrent MiM attack. There are two ways to construct a multi-trapdoor ...
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### How does CBC ESSIV disk encryption handle IV reuse?

From what I've read, ESSIV deterministically generates an IV from the encryption key and the sector number. When I change a sector on the drive, and it gets encrypted, how does it handle IV reuse?
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### Example of an attack on a message exchange which uses the homomorphic property

Can someone give me an example of an attack on a message exchange using this encryption scheme, that uses the homomorphic property? Note: It is not a homework question.
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### encrypt data without a key, length stays the same, result differs each time? [on hold]

I am attempting to solve my friends encryption algorithm, however I have yet to even believe such a thing is possible: Rules: the cipher must result in the same length, the encryption process does ...
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### Could a 6502 CPU safely compute a SHA-1 hash in a reasonable length of time?

The 6502 is the CPU in a Tamagotchi (which can be hacked to run custom code). SHA-1 is the default hash used for TOTP (the algorithm used by two-factor authentication tokens and apps). Hopefully you ...
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### Triple Data Encryption Standard

Based on this, it looks like something slightly wrong. What would need to be adjusted at the transmitter side to allow the receiver to decrypt the message/data?
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### How to provide partial confidentiality and full integrity for a protocol message?

I want to provide confidentiality and integrity for a protocol. I don't want to encrypt the entire protocol message. I do not want to encrypt the header and timestamp of the protocol message, but I ...
28 views

### ECDSA signature uniqueness

I've been trying to replicate an ECDSA signing process that a cryptosystem uses (EOS, in this case), and I've been having issues. Namely, testing my c++ code (which uses openSSL) and comparing the ...
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### Can I use PKCS#5 with CBC? [duplicate]

As far as I know there are two padding mechanisms, which are PKCS 5 and 7. Which one should be used for CBC?
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### How do i manage encryption keys with a cloud provider?

I would like to provision services from a Software as a Service (SaaS) provider. This is multitenant environment (multiple companies will be using a single instance of the application, with a single ...
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### Can anyone explain the mathematics behind Elliptic curve Signature generation and verification(ECDSA)? [on hold]

I know that there are two components r and s in a signature but I am trying to understand what are these values in terms of elliptic curve co-ordinates, the curve equation and also modular arithmetic ...
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### When do I need to use CBC and HMAC?

As I know CBC does not provide integrity for the message, thus HMAC is used to provide integrity for CBC message. Also, I hear about CBC-MAC which can provide integrity and confidentiality. Which one ...
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### Key Agreement, one end Bouncy Castle, the other end OpenSSL/TomLibCrypt [on hold]

I am struggling like mad, I have an existing system using tomlibcrypt to verify a key agreement, and when running key agreement in openSSL the two agree byte for byte on the shared key. However when ...

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