A substitution cipher is an encryption algorithm which works by replacing plaintext units with corresponding ciphertext units, following some rule depending on the key.
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Is this hand cipher any more secure than the Vigenère cipher?
I know that inventing one's one crypto always sucks, but the problem is that hand ciphers are usually 1. very insecure 2. very slow. This is an attempt to make a relatively secure, keyable, and ...
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Chosen Plaintext Attacks
Assuming the ability to launch Chosen Plaintext Attacks (CPA), how many oracle calls an attacker
needs to break the affine cipher? and how
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My Hand Cipher, Can some one tell if it secure [closed]
In easy steps how it works,
Convert txt to numbers . mod 1-26.
Generate random numbers (By my other cipher) equal to plain txt.
Write random numbers under txt numbers.
txt= LOI - txt number= 12 15 ...
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Cracking the beaufort cipher
Is there any easy way to crack a beaufort cipher?
We have a vigenere table, and are trying to guess the keyword.
Any easier way?
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Possible ways to crack simple substitution ciphers
We had a quiz in class today where we had to break the ciphertext with the key given, but not the algorithm. Suffice to say that I wasn't able to decrypt it within the alloted time of 12 mins and will ...
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Making a cipher (ex: Vigenere) harder to break
The Vigenere cipher can relatively easy be broken when the key size is small compared to the size of the message. One first finds the length of the key, and then uses frequency analysis to actually ...
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Relative security of a Vigenère cipher
Within a closed computer network, I am ciphering some plaintext data as an added security measure. This is below several other layers of protection. For various technical reasons, I am restricted to ...
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Toy cipher — does it have a name?
When I was perhaps nine years, I borrowed a book from the library on various maths and CS topics. It outlined various simple ciphers, including one that I used a lot, just for fun. I can't remember ...
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How to get the keyword from a keyword cipher?
I was given a ciphertext and now I am trying to break it via looking for the keyword.
This is a keyword cipher. So:
PlainEnglish: ABCDEFGHIJKLMNOPQRSTUVWXYZ
If ...
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Existing dictionaries of popular words to help solve a random substitution cipher?
I'm trying to find faster ways to solve this:
http://cryptogram.org/solve_cipher.html
Actually lists of common words are good, but they are often limited to 1000 words.
I found this, but I'm not ...
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Encryption/ciphers/codes in Chinese
I am quite curious as to how you can perform simple encryption for the Chinese language.
Saw a similar question related to encryption/Chinese here: About cryptography in a character language, ...
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Is a book cipher provably secure?
I've seen ciphers (usually in spy drama shows) that involve taking a book and writing down an index to individual characters. Essentially it's a keyed substitution cipher, where the key is the name ...
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How can one break a monoalphbetic substitution chipher at pseudorandom text?
Does anybody know how to break monoalphbetic substitution cipher, if it is applied to some pseudorandom text (for example to some surrogate key filed in a database)?
Let us assume that we have only ...
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Using a mono-alphabetic substitution cipher with a different language per word
How much harder is it to determine the secret key for a mono-alphabetic substitution cipher, if each word is translated into a different language before the cipher is applied?
EDIT
If somehow ...
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1answer
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What is the best method to determine the language used in a monoalphabetic substitution cipher?
Working on a cipher (which I assume to be a mono-alphabetic substitution cipher due to the letter frequency) I struggle with the fact that I don't know which language the plain text is written in. ...
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Alphabetic Substitution with Symbols
I was reading on a site about the Zodiac Killer and how he used a basic substitution cipher, but instead of substituting english letters and characters he substituted symbols.
I was wondering, if you ...
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Can an Enigma-style cipher of sufficient complexity be considered secure in today's world?
Regarding the German Enigma machines, if I recall correctly, the reason they were defeated was because the Allies were able to generate a massive database of possible rotor settings, and because the ...
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About Cryptography in a Character Language
Suppose I had a message in Chinese (or another non-phonetic language) and I wanted to encipher it.
Some of the simplest encryptions in English are substitution ciphers, but such ciphers don't seem ...
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What are the main weaknesses, if any, of a Playfair cipher?
What are the main weaknesses, if any, of a Playfair cipher?
I know that they depend on none of the letters missing, but that is an easy fix if a letter gets dropped. Besides that, are there any other ...
