# A report on Cryptography

Practice and study of techniques for secure communication in the presence of adversarial behavior.

- Cryptography130 related topics with Alpha

## Cryptanalysis

19 linksCryptanalysis (from the Greek kryptós, "hidden", and analýein, "to analyze") refers to the process of analyzing information systems in order to understand hidden aspects of the systems.

Cryptanalysis (from the Greek kryptós, "hidden", and analýein, "to analyze") refers to the process of analyzing information systems in order to understand hidden aspects of the systems.

Cryptanalysis is used to breach cryptographic security systems and gain access to the contents of encrypted messages, even if the cryptographic key is unknown.

## Public-key cryptography

18 linksCryptographic system that uses pairs of keys.

Cryptographic system that uses pairs of keys.

The generation of such key pairs depends on cryptographic algorithms which are based on mathematical problems termed one-way functions.

## Data Encryption Standard

15 linksSymmetric-key algorithm for the encryption of digital data.

Symmetric-key algorithm for the encryption of digital data.

Although its short key length of 56 bits makes it too insecure for modern applications, it has been highly influential in the advancement of cryptography.

## Block cipher

13 linksIn cryptography, a block cipher is a deterministic algorithm operating on fixed-length groups of bits, called blocks.

## Cipher

10 linksIn cryptography, a cipher (or cypher) is an algorithm for performing encryption or decryption—a series of well-defined steps that can be followed as a procedure.

## Ciphertext

10 linksIn cryptography, ciphertext or cyphertext is the result of encryption performed on plaintext using an algorithm, called a cipher.

## Diffie–Hellman key exchange

10 linksMethod of securely exchanging cryptographic keys over a public channel and was one of the first public-key protocols as conceived by Ralph Merkle and named after Whitfield Diffie and Martin Hellman.

Method of securely exchanging cryptographic keys over a public channel and was one of the first public-key protocols as conceived by Ralph Merkle and named after Whitfield Diffie and Martin Hellman.

DH is one of the earliest practical examples of public key exchange implemented within the field of cryptography.

## One-time pad

8 linksIn cryptography, the one-time pad (OTP) is an encryption technique that cannot be cracked, but requires the use of a single-use pre-shared key that is not smaller than the message being sent.

## Substitution cipher

9 linksIn cryptography, a substitution cipher is a method of encrypting in which units of plaintext are replaced with the ciphertext, in a defined manner, with the help of a key; the "units" may be single letters (the most common), pairs of letters, triplets of letters, mixtures of the above, and so forth.