Sha256: d964234b8cc1555422c0e3c1c519d3c96ca4b5710c136a921019d0d791fc3e85
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Versions: 17
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Contents
require "openssl"
module Shamu
module Security
# Adds support for hashing and verifying a string value.
#
# ```ruby
# class Codec
# include Shamu::Security::HashedValue
#
# def initialize( private_key = Shamu::Security.private_key )
# @private_key = private_key
# end
#
# def store( value )
# hash_value( value )
# end
#
# def restore( hashed )
# verify_hash( hashed )
# end
# end
#
# codec = Codec.new
# signed = codec.store "example" # => "0123456789abcdef0123456789abcdef012345678;example"
# codec.restore signed # => "example"
# codec.restore "example" # => nil
# ```
module HashedValue
private
# @!visiblity public
# @return [String] the private key used to sign the hashes.
attr_reader :private_key
# @!visibility public
#
# @param [String] string to hash.
# @return [String] packed string with hash and original value.
def hash_value( string )
return nil unless string
"#{ hash_digest( string ) }$#{ string }"
end
def hash_digest( string )
alg = OpenSSL::Digest::SHA1.new
OpenSSL::HMAC.hexdigest( alg, private_key, string )
end
# @!visiblity public
#
# Verify that the hashed value has not been modified.
#
# @param [String] hashed value returned from {#hash_value}.
# @return [String] the original value.
def verify_hash( hashed )
return unless hashed
return if hashed.length < 41
mac = hashed[ 0...40 ]
toggles = hashed[ 41..-1 ]
return unless hash_digest( toggles ) == mac
toggles
end
end
end
end
Version data entries
17 entries across 17 versions & 1 rubygems