Class: JWT::JWA::Hmac

Inherits:
Object
  • Object
show all
Includes:
SigningAlgorithm
Defined in:
lib/jwt/jwa/hmac.rb

Overview

Implementation of the HMAC family of algorithms

Defined Under Namespace

Modules: SecurityUtils

Constant Summary collapse

MIN_KEY_LENGTHS =

Minimum key lengths for HMAC algorithms based on RFC 7518 Section 3.2. Keys must be at least the size of the hash output to ensure sufficient entropy for the algorithm's security level.

{
  'HS256' => 32,
  'HS384' => 48,
  'HS512' => 64
}.freeze

Instance Attribute Summary

Attributes included from SigningAlgorithm

#alg

Instance Method Summary collapse

Methods included from SigningAlgorithm

#header, #raise_sign_error!, #raise_verify_error!, #valid_alg?

Constructor Details

#initialize(alg, digest) ⇒ Hmac

Returns a new instance of Hmac.



18
19
20
21
 
# File 'lib/jwt/jwa/hmac.rb', line 18

def initialize(alg, digest)
  @alg = alg
  @digest = digest
end

Instance Method Details

#sign(data:, signing_key:) ⇒ Object 



23
24
25
26
27
28
 
# File 'lib/jwt/jwa/hmac.rb', line 23

def sign(data:, signing_key:)
  ensure_valid_key!(signing_key)
  validate_key_length!(signing_key)

  OpenSSL::HMAC.digest(digest.new, signing_key, data)
end

#verify(data:, signature:, verification_key:) ⇒ Object 



30
31
32
33
34
35
 
# File 'lib/jwt/jwa/hmac.rb', line 30

def verify(data:, signature:, verification_key:)
  ensure_valid_key!(verification_key)
  validate_key_length!(verification_key)

  SecurityUtils.secure_compare(signature, OpenSSL::HMAC.digest(digest.new, verification_key, data))
end