Security Protocols
Many of the protocols listed are from the book, "Applied Cryptography" by Bruce Schneier and are listed for reference only. They are grouped by their function. Some may have overlapping functions. For more details about their strengths, weaknesses, and characteristics, please read "Applied Cryptography".
Key exchange Algorithms
 COMSET
 Conference Key Distribution
 DiffieHellman
 Encrypted Key Exchange (EKE)
 Shamir's Three Pass Protocol
 TatebayashiMatsuzakiNewman
Public Key Cipher Algorithms
 ElGamel
 LUC
 McEliece
 Knapsack
 PohligHellman
 Rabin
 RSA  Public key algorithm for digital signatures
Public Key Digital Signature Algorithms
 Cellular Automata
 DSA (NSA)
 ESIGN
 GOST
 OngSchnorrShamir
Block Cryptographic Algorithms
These algorithms encrypt data in blocks. Each block is a specific number of bits.
 3Way  Uses a 96 bit key and block length. No known cryptoanalysis has been done. It appears to be a good algorithm. *
 Blowfish  Created by Bruce Schneier for the public domain. Key length varies up to 448 bits with a 64 bit block. Not secure if the number of rounds are reduced but otherwise it is a good algorithm in the public domain.
 CA1.1  1088 bit key with 384 bit blocks. Strength is untested.
 CAST  Uses a 64 bit key and block size. Resists linear and differential cryptoanalysis.
 CRAB  Similar to MD5. Uses a 1024 bit block and can accept variable length keys. No key generation is included. Not intended as a working algorithm.
 DES  Data Encryption standard also known as data encryption algorithm (DEA). Symmetric with 56 bit key.
 FEAL  Uses 64 bit keys and blocks. Weak against plaintext cryptoanalysis attacks.
 GOST  Developed in the USSR, it uses 64 bit block with a 256 bit key. Secure against brute force. May be a good algorithm. *
 IDEA  International Data Encryption algorithm uses a 128 bit key and 64 bit block. This algorithm appears strong and is recommended as the most currently secure algorithm by some experts. It is twice as fast as DES.*
 Khafre  64 or 128 bit keys. Can be broken using plaintext attacks.
 Khufu  Uses a 512 bit key and 64 bit block. Secure against brute force attacks.
 LOKI  Uses a 64 bit block and 64 bit key. LOKI is not secure but LOKI91 is more secure if keys are managed correctly.
 Lucifer  Not very secure.
 MMB  Modular Multiplication based Block cipher uses a 64 Bit block and a 128 bit key.
 RC2  Variable key size with 54 bit block. This algorithm is not public.
 RC5  Block and key size are variable.
 REDOC II  Uses a 160 bit key with an 80 bit block. Strong against brute force attacks
 REDOC III  Uses a variable key length and 80 bit block. Fast but not secure.
 SAFER  Secure And Fast Encryption Routine uses 8 byte blocks. It is secure against linear cryptoanalysis and is resistand to differential cryptoanalysis. It has the following variants:
 SAFER K64  64 bit keys. There is a weakness in the key schedule.
 SAFER K128  128 bit keys. compensates for the key schedule weakness.
 SEAL
 Skipjack  Developed by NSA. The algorithm is secret. Uses an 80 bit key and 64 bit block. Security is unknown.
 SXAL8/MBAL
 WAKE
Works on bytes:


 Madryga  Key lengths are adjustable. Not recommended by some experts.
 NewDES  Uses a 120 bit key but is not as strong as DES.
Stream Cryptographic Algorithms
These algorithms encrypt data in streams and use hardware to perform the functions.
 A5  It is effiecient but may not be very secure due to short registers.
 Algorithm M
 Gifford
 Nanoteq
 PKZip  Used in the PKZIP file compression program. Security is not very good.
 Rambuyan
 RC4
 SEAL
 WAKE
 XPD/KPD
Authentication
 Salt  A random number string is combined with the user password before a one way function is applied to it. The salt value and the one way function result are stored on the host that authenticated the user. The password is not stroed on the host.
 SKEY  A one way function authentication mechanism. A limited set of numbers are generated by using the function on a random number, then use the function on each result for a given number of times. The generated numbers are used only once for login.
 SKID, SKID2, and SKID3
Combined Authentification and Key Exchange
These protocols depend on the use of a trusted server.
 DASS  Uses symmetric and public key exchange.
 DenningSacco  Uses public key exchange.
 Kerberos  Depends on clocks synchronized with the trusted server. Uses symmetric key exchange.
 NeedhamSchroeder  Uses symmetric key exchange.
 NeumanStubblebine  Is an improvement on Yaholom and does not depend on synchronized clocks to prevent a replay attack. Uses symmetric key exchange.
 OtwayRees  Uses symmetric key exchange.
 Widemouth frog  Uses symmetric key exchange.
 WooLam  Uses public key exchange.
 Yaholom  Uses symmetric key exchange.
Identification Schemes
 FeigeFiatShamir
 GuillonQuisquater
 Schnorr
One way Hash Functions
 GOST
 HAVAL  Produces a variable length hash value.
 karn
 Luby_Rackoff
 MD4,5,2  Message Digest
 NHash  Not very secure unless a high number of rounds are used.
 RIPEMD  Produces a 128 bit hash value.
 Secure Hash Algorithm (SHA)  Creates a 160 bit hash value.
 Snefru  If made secure, is slower than other algorithms.
MAC
Message Authentication Codes (MAC) are dependent on hash functions to authenticate messages. They are used to be sure files and messages have not been modified.
 MAA  Message Authenticator Algorithm
 RIPEMAC
 IBCHash
