Adding Password Protection to Your Embedded Project

Password Screen


Password Screen
Enter Password

Passwords and such small bits and pieces of information are generally stored in eeproms in digital systems. While developing such a system the general methodology is that the user is made to enter a predefined length of characters which is encrypted using an algorithm and a key. This encrypted password is then stored into the eeprom or similar memory.

The alternative approach is to use a hash function. The hash function converts the large data into a small datum and this value is called a hash value. Cryptographic hash has certain properties. The ideal cryptographic hash function has four main or significant properties:

  • it is easy (but not necessarily quick) to compute the hash value for any given message
  • it is infeasible to generate a message that has a given hash
  • it is infeasible to modify a message without changing the hash
  • it is infeasible to find two different messages with the same hash

A very popular example is the MD5 or Message Digest 5 hash. These are commonly used to verify the integrity of messages and even files.

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