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, TLS / SSL, Cisco type 5 enable passwords, and RADIUS. Software Implementations of MD5 Ready-to-use MD5 implementations are available in C, C++, JavaScript, PERL, ActiveX, and Delphi. The Difficulty of a Brute Force Attack Against MD5 The difficulty of creating two Read More

DES (Data Encryption Standard) is a symmetric cipher defined in Federal Information Processing (FIPS) Standard Number 46 in 1977 as the federal government approved encryption algorithm for sensitive but non-classified information. DES was developed by IBM and was based upon IBM’s earlier Lucifer cipher. DES utilizes a 56-bit key. This key size is vulnerable to a brute force attack using current technology. Triple DES A variant of DES, Triple DES, provides significantly enhanced security by executing the core DES algorithm three times in a row. The has the effect of Read More

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 identities, and induct them into the user database. Certification Authority The tasks of a Certification Authority are to issue public key certificates and to attest that the public key embedded in it indeed belongs to the particular entity as stated in the certificate. The Certification Authority also has the right to Read More

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 passport. Digital certificates are issued by a third party known as a Certification Authority such as VeriSign or Thawte. These third party certificate authorities have the responsibility to confirm the identity of the certificate holder as well as provide assurance to the website Read More

Certificate Authority or Certification Authority (CA) is an entity, which is core to many PKI (Public Key Infrastructure) schemes, whose purpose is to issue digital certificates to use by other parties. It exemplifies a trusted third party. Some certification authorities may charge a fee for their service while some other CAs are free. It is also not uncommon for government and institutions to have their own CAs. More about Issuing a Certificate The certification authority issues a Public Key Certificate (PKC), which attests that the public key embedded in it Read More

A known ciphertext attack is an an attack where the cryptanalyst only has access to encrypted ciphertext. A known ciphertext attack is the easiest of the common cryptanalysis attacks to mount, because is requires the least amount of control over the encryption device. Conversely, the known ciphertext is the most difficult of the common methods of cryptanalysis to execute successfully, because so little knowledge is known to begin with.

TrueCrypt is a free, open source disk encryption software that is available for the Windows XP, Windows Vista, Windows 7, Mac, Linux, and Unix operating systems. TrueCrypt provides users with real time encryption/decryption, parallelization and pipelining to read/write to partitions as fast as non-encrypted partitions, and plausible deniability through hidden volumes and hidden operating systems in order to hide the user’s data even if he/she is forced to reveal his/her password.   How TrueCrypt Works TrueCrypt works by creating a virtual encrypted disk within a file and mounting it as Read More

Block and Stream Ciphers are two categories of ciphers used in classical cryptography. Block and Stream Ciphers differ in how large a piece of the message is processed in each encryption operation. Block Ciphers Block ciphers encrypt plaintext in chunks. Common block sizes are 64 and 128 bits. Stream Ciphers Stream ciphers encrypt plaintext one byte or one bit at a time. A stream cipher can be thought of as a block cipher with a really small block size. Block Ciphers vs. Stream Ciphers Generally speaking, block ciphers are more Read More

A message digest is a number which is created algorithmically from a file and represents that file uniquely. If the file changes, the message digest will change. In addition to allowing us to determine if a file has changed, message digests can also help to identify duplicate files. Creating a Message Digest On many Unix systems, the `md5` command wll generate a message digest: bash-2.05a$ md5 /kernel MD5 (/kernel) = cdd6056e13686981c50ca6008782732a On older legacy Unix systems, the `sum` command was utilized for the same purpose. bash-2.05a$ sum /kernel 33504 4188 Read More

RSA, which stands for Rivest, Shamir, and Adleman, is a security algorithm used in digital cryptography. RSA differs from older symmetric algorithms because it has the ability of allowing digital signing as well as advanced encryption for online commerce systems and high-profile institutions. RSA was one of the first major advancements in digital cryptography but is now widely used to secure financial, personal, and corporate-level information for a variety of domestic and commercial users. How RSA Works RSA involves the use of three individual functions. The first function of RSA Read More