What is DES?

  • 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 .

    It was developed by IBM in co-operation with the American National Security Agency and published in 1974. It has become extremely popular and, because it used to be so difficult to break, with 72,000,000,000,000,000 possible key variations, was banned from export from the USA. However, restrictions by the US Government, on the export of encryption technology was lifted in 2000 to the countries of the EU and a number of other countries.

  • 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 making the DES encryption much more difficult to brute force. Triple-DES is estimated to be 2 to the 56th times more difficult to break than DES. Triple DES can still be considered a secure encryption algorithm. Triple DES is also written as 3-DES or 3DES.

    DES and AES
    DES - The Data Encryption Standard and the AES - Advanced Encryption Standard are both data encryption standards for the scrambling of data to protect its confidentiality.

    DES is being replaced by AES, the Advanced Encryption Standard or Rijndael .

    DES and Triple-DES will remain in service for many decades.

    What is AES (Rijndael) ?
    The AES - Advanced Encryption Standard, is a state of the art algorithm (developed by Rijndael) and chosen by the United States National Institute of Standards and Technology on October 2, 2000. Although selected, it will not become officially "approved" by the US Secretary of Commerce until Q2 2001. Meanwhile, products are already available which use the Rijndael algorithm within AES encryption tools. For example

    AES (Advanced Encryption Standard) is a symmetric cipher defined in Federal Information Processing (FIPS) Standard Number 197 in 2001 as the federal government approved encryption algorithm.

    The NSA has approved 128-bit AES for use up to SECRET level and 192-bit AES for use up to TOP SECRET level.

    AES is based upon the Rijndael algorithm, which was invented by Joan Daemen and Vincent Rijmen. AES specifies three approved key lengths: 128-bits, 192-bits and 256-bits.

    Nicolas Courtois maintains an excellent web page on the current state of attacks on AES.

    What is RSA ?
    RSA is an asymmetric cipher defined in U.S. Patent 4,405,829 in 1977, the same year that IBM's algorithm was selected as the Data Encryption Standard. The RSA patent expired on 20 September, 2000.

    The RSA algorithm is named after it's three creators: Ron Rivest, Adi Shamir, and Leonard Adleman.

    What is PGP?

    PGP(tm) uses public-key encryption to protect E-mail and data files. Communicate securely with people you've never met, with no secure channels needed for prior exchange of keys. PGP is well featured and fast, with sophisticated key management, digital signatures, data compression, and good ergonomic design.

  • Pretty Good(tm) Privacy (PGP), from Phil's Pretty Good Software, is a high security cryptographic software for MS-DOS, Unix, VAX/VMS, and other computers. PGP allows people to exchange files or messages with privacy, authentication, and convenience. Privacy means that only those intended to receive a message can read it.

    Authentication means that messages that appear to be from a particular person can only have originated from that person. Convenience means that privacy and authentication are provided without the hassles of managing keys associated with conventional cryptographic software. No secure channels are needed to exchange keys between users, which makes PGP much easier to use. This is because PGP is based on a powerful new technology called "public key" cryptography.

  • PGP combines the convenience of the Rivest-Shamir-Adleman (RSA) public key cryptosystem with the speed of conventional cryptography, message digests for digital signatures, data compression before encryption, good ergonomic design, and sophisticated key management. And PGP performs the public-key functions faster than most other software implementations. PGP is public key cryptography for the masses.

    PGP Freeware 6.5.8 includes support for both RSA (Rivest Shamir Adleman) and Diffie-Hellman keys.

    PGP may be downloaded from the MIT Distribution Center for PGP at

  • What is GPG: GNU Privacy Guard

    Many users have replaced PGP with GPG: GNU Privacy Guard.

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