Cryptography

Cryptography is a method of protecting information and communications through the use of codes so that only those for whom the information is intended can read and process it. It is a science of making ciphers or algorithms.
Cryptanalytics is a science of Breaking Cipher. Cryptography & Cryptanalytics together is known as Cryptology.
These Algorithm are published in public domain. It also relies on secret piece of information called as key

Cryptographic algorithms has to achieve

  • Confidentiality

    • It assures that confidential information is not disclosed to unauthorized individuals. It is also related to storage & Transmission of Information. For Example :

      Military - It used for the Concealment of sensitive Information
      Industry - Hiding critical information from competitors
      Banking - Customer accounts needs to be kept secured incase of unauthorised access

  • Integrity

    • Information to be communicated keeps changing. This change should be made by authorised users only

  • To ensure integrity of data
  • Prevent modification
  • Detect any modification made

  • Availability

    • Confidentiality and integrity should not hinder availability of data. It should be noted that

  • Service is not denied to authorized users
  • Cryptographic mechanism cause overhead
  • Therefore fast mechanism should be used so that systems work promptly

    • Cryptography can also do things like

  • Digital Signatures - Function of Content of Document
  • Anonymous Communication - Communication uses proxies. Identity of the user is encrypted