MD5 is a message digest algorithm. MD5 takes a variable length input and produces a 128-bit message digest. MD5 was designed by Ron Rivest in 1991. MD5 is officially defined in RFC 1321 - The MD5 Message-Digest Algorithm. MD5 Usage MD5 is used in many applications, including GPG, Kerberos, T
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Substitution and transposition ciphers are two categories of ciphers used in classical cryptography. Substitution and transposition differ in how chunks of the message are handled by the encryption process. Substitution ciphers Substitution ciphers encrypt plaintext by changing the plaintext one p
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RC4 is a symmetric stream cipher with an arbitrary key size. RC4 was created by Ron Rivest of RSA Security in 1987. RC4 is used in many applications, including TLS (Transport Layer Security), WEP (Wired Equivalent Privacy), WPA (Wi-Fi Protected Access), TKIP (Temporal Key Integrity Protocol), Mic
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Digital certificates are the equivalent of a driver's license, a marriage license, or any other form of identity. The only difference is that a digital certificate is used in conjunction with a public key encryption system. Digital certificates are electronic files that simply work as an online
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A Root Certificate is a self-signed certificate or an unsigned public key certificate which forms an important part of the PKI (public key infrastructure). The most common commercial type of root certificates is based on the ISO X.509 standard. Such a certificate (a X.509 certificate) usually carrie
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A one-time pad is the only theoretically unbreakable cipher. A one-time pad is a private key, or symmetric, cipher where the key size is equal to the plaintext size. Because of this, the key is never reutilized. As the key is never reutilized, there is no basis for mathematical cryptanalysis. An
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Cryptology Cryptology is the science which incorporates both cryptography and cryptanalysis. Cryptologists Practitioners of cryptology are known as cryptologists. Cryptology in Context A cryptographer will use cryptography to convert plaintext into ciphertext and a cryptanalyst will use cryptan
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Kerberos is a network authentication protocol which utilizes symmetric cryptography to provide authentication for client-server applications. Kerberos Standard Definition Kerberos is defined in RFC 1510 - The Kerberos Network Authentication Service (V5). Kerberos Architecture The core of Kerbe
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PKI Authorities consists of three different authorities that essentially make up a PKI system. These are the Registration Authority, Certification Authority and Certificate Directory. Registration Authority The jobs of the Registration Authority are to processes user requests, confirm their identi
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Diffie-Hellman is an asymmetric cipher defined in U.S. Patent 4,200,770 in 1977, the same year that IBM's algorithm was selected as the Data Encryption Standard. The Diffie-Hellman patent expired on 6 September, 1997. The Diffie-Hellman algorithm is named after its creators: Whitfield Diffie a
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