https://github.com/jtdowney/cmac

Ruby implementation of the Cipher-based Message Authentication Code (CMAC)
https://github.com/jtdowney/cmac

Last synced: 3 months ago
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Ruby implementation of the Cipher-based Message Authentication Code (CMAC)

• Host: GitHub
• URL: https://github.com/jtdowney/cmac
• Owner: jtdowney
• License: mit
• Created: 2012-11-23T13:38:42.000Z (about 12 years ago)
• Default Branch: main
• Last Pushed: 2020-06-16T01:49:36.000Z (over 4 years ago)
• Last Synced: 2024-03-14T22:24:26.331Z (10 months ago)
• Language: Ruby
• Homepage:
• Size: 15.6 KB
• Stars: 3
• Watchers: 2
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE
  • Code of conduct: CODE_OF_CONDUCT.md

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README

        
# CMAC [![Build Status](https://secure.travis-ci.org/jtdowney/cmac.png?branch=main)](https://travis-ci.org/jtdowney/cmac)

This gem is ruby implementation of the Cipher-based Message Authentication Code (CMAC) as defined in [RFC4493](http://tools.ietf.org/html/rfc4493), [RFC4494](http://tools.ietf.org/html/rfc4494), and [RFC4615](http://tools.ietf.org/html/rfc4615). Message authentication codes provide integrity protection of data given that two parties share a secret key.

```ruby

key = OpenSSL::Random.random_bytes(16)

message = 'attack at dawn'

cmac = CMAC.new(key)

cmac.sign(message)

 => "\xF6\xB8\xC1L]s\xBF\x1A\x87<\xA4\xA1Z\xE0f\xAA"

```

Once you've obtained the signature (also called a tag) of a message you can use CMAC to verify it as well.

```ruby

tag = "\xF6\xB8\xC1L]s\xBF\x1A\x87<\xA4\xA1Z\xE0f\xAA"

cmac.valid_message?(tag, message)

 => true

cmac.valid_message?(tag, 'attack at dusk')

 => false

```

CMAC can also be used with a variable length input key as described in RFC4615.

```ruby

key = 'setec astronomy'

message = 'attack at dawn'

cmac = CMAC.new(key)

cmac.sign(message)

 => "\\\x11\x90\xE6\x91\xB2\xC4\x82`\x90\xA6\xEC:\x0E\x1C\xF3"

```