Encryption algorithms

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Compression algorithms Character sets Hashing algorithms

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Encryption is the process of converting a plaintext message into ciphertext which can be decoded back into the original message. An encryption algorithm along with a key is used in the encryption and decryption of data. There are several types of data encryptions which form the basis of network security. Encryption schemes are based on block or stream ciphers.

The type and length of the keys utilized depend upon the encryption algorithm and the amount of security needed. In conventional symmetric encryption a single key is used. With this key, the sender can encrypt a message and a recipient can decrypt the message but the security of the key becomes problematic. In asymmetric encryption, the encryption key and the decryption key are different. One is a public key by which the sender can encrypt the message and the other is a private key by which a recipient can decrypt the message.


Glossary:

Asymmetric encryption algorithm.
A modern branch of cryptography. also known as public-key cryptography in which the algorithms employ a pair of keys (a public key and a private key) and use a different component of the pair for different steps of the algorithm.

Block cipher.
These algorithms work on chunks of specific sized data along with a key resulting in blocks of cipher text. The National Institute of Standards and Technology (NIST) is a federal agency that approved the Data Encryption Standard (DES) block cipher an early encryption algorithm created in the mid 1970s. The American National Standards Institute (ANSI) also set this security algorithm as the Data Encryption Algorithm (DEA) standard. Another standard developed in the 1980s is the Triple Data Encryption Standard (3DES). Some commonly used block cipher algorithms are IDEA, RC2, RC5, CAST and Skipjack.

CBC, Cipher Block Chaining.
Encryption mode.

CBD, Cipher block chaining mode.
The results of the previously chained block is used in the encryption of the next chained block.

CCM, Counter with CBC-MAC.
Encryption mode. A generic authenticated encryption block cipher mode. This mode is defined for use with 128-bit block ciphers such as AES.

CFB, Cipher FeedBack.
Encryption mode.

Chinese Lottery.
A cryptographic approach to cracking encryption algorithms utilizing a large number of machines across the Internet.

Cipher algorithm.
A mechanism used to encrypt or decrypt a message.

Ciphertext.
The resulting encrypted message produced by a cipher algorithm.

CTR, Counter.
Encryption mode.

Decryption.
The process of making a encrypted message recognizable with a cipher algorithm.

ECB, Electronic Code Book.
Encryption mode.

Encryption.
The process of making a message unrecognizable with a cipher algorithm.

Encryption key.
A sequence of values that are used with a cipher algorithm to encrypt a message. The choice of random (or cryptographically pseudorandom) keys, a secure key exchange mechanism, frequent key refreshments, and good secrecy protection of keys are all essential ingredients for the security of the integrity verification mechanism.

OFB, Output FeedBack.
Encryption mode.

Plaintext.
An unencrypted message.

Private key.
(RFC 2828) The secret component of a pair of cryptographic keys used for asymmetric cryptography. In a public key cryptosystem that key of a user's key pair which is known only by that user.

Public key
A public key which encrypts a message. (RFC 2828) The publicly-discloseable component of a pair of cryptographic keys used for asymmetric cryptography. In a public key cryptosystem, that key of a user's key pair which is publicly known.

Public key encryption.
An encryption mechanism where two keys are used. A public key is used to encrypt the message and a secret private key to decrypt the message.

Secret key.
A single secret key which is used in conventional symmetric encryption which is used to encrypt and decrypt a message.

SIV, Synthetic Initialization Vector.
Block cipher mode of operation.
(RFC 5297) SIV takes a key, a plaintext, and multiple variable-length byte strings that will be authenticated but not encrypted. It produces a ciphertext having the same length as the plaintext and a synthetic initialization vector. Depending on how it is used, SIV achieves either the goal of deterministic authenticated encryption or the goal of nonce-based, misuse-resistant authenticated encryption.

Stream cipher.
A symmetric encryption algorithm that processes the data a bit or a byte at a time with a key resulting in a randomized ciphertext or plaintext. Some commonly used stream cipher algorithms are RC4 and W7.

Symmetric encryption algorithm.
The encryption key and the decryption key are interrelated and may even be the same.


3

3DES.
Block cipher algorithm.


A

AES, Advanced Encryption Standard.
Block cipher algorithm.

ARIA.
Block cipher algorithm.


B

Blowfish.
Block cipher algorithm.


C

Camellia.
Block cipher algorithm.

CAST.
Block cipher algorithm.

CLEFIA.
Block cipher algorithm.

CMAC.
Block cipher algorithm.


D

DES, Data Encryption Standard.
Block cipher algorithm.


G

GOST 28147.
Symmetric cipher algorithm.

[RFC 4357] Additional Cryptographic Algorithms for Use with GOST 28147-89, GOST R 34.10-94, GOST R 34.10-2001, and GOST R 34.11-94 Algorithms.

[RFC 4490] Using the GOST 28147-89, GOST R 34.11-94, GOST R 34.10-94, and GOST R 34.10-2001 Algorithms with Cryptographic Message Syntax (CMS).


I

IDEA, International Data Encryption Algorithm.
Block cipher algorithm.


M

Mars.
Block cipher algorithm.

MISTY1.
Block cipher algorithm.


R

Rabbit.
Stream cipher algorithm.

RC2.
Block cipher algorithm.

RC4.
Stream cipher algorithm. A proprietary encryption algorithm available under license from RSA Data Security Inc.

RC5.
Block cipher algorithm.

RC6.

Rijndael.
Block cipher algorithm. The winning algorithm of the AES competition.


S

SEED.
Block cipher algorithm.

SKIPJACK.
Block cipher algorithm.

SOBER.
Stream cipher algorithm.


T

Twofish.
Block cipher algorithm.


W

W7.
Stream cipher algorithm. A byte wide, synchronous stream cipher optimized for efficient hardware implementation at very high data rates. It is a symmetric key algorithm supporting key lengths of 128 bits.


RFCs:

[RFC 3766] Determining Strengths For Public Keys Used For Exchanging Symmetric Keys.

[RFC 4107] Guidelines for Cryptographic Key Management.

[RFC 4270] Attacks on Cryptographic Hashes in Internet Protocols.


Publications:


Obsolete RFCs:


Description Glossary RFCs Publications Obsolete RFCs