Triple DES

What Does Triple DES Mean?

Triple Data Encryption Standard (DES) is a type of computerized cryptography where block cipher algorithms are applied three times to each data block. The key size is increased in Triple DES to ensure additional security through encryption capabilities. Each block contains 64 bits of data. Three keys are referred to as bundle keys with 56 bits per key. There are three keying options in data encryption standards:

  1. All keys being independent
  2. Key 1 and key 2 being independent keys
  3. All three keys being identical

Key option #3 is known as triple DES. The triple DES key length contains 168 bits but the key security falls to 112 bits.

Techopedia Explains Triple DES

Triple DES is advantageous because it has a significantly sized key length, which is longer than most key lengths affiliated with other encryption modes. However, the DES algorithm was replaced by the Advanced Encryption Standard by the National Institute of Standards and Technology (NIST). Thus, the Triple DES is now considered to be obsolete. Yet, it is often used in conjunction with Triple DES. It derives from single DES but the technique is used in triplicate and involves three sub keys and key padding when necessary, such as instances where the keys must be increased to 64 bits in length. Known for its compatibility and flexibility, software can easily be converted for Triple DES inclusion. Therefore, it may not be nearly as obsolete as deemed by NIST.

Triple DES encrypts input data three times. The three keys are referred to as k1, k2 and k3. This technology is contained within the standard of ANSIX9.52. Triple DES is backward compatible with regular DES.


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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.