rubocop

lib/minisign/private_key.rb

@@ -1,62 +1,40 @@
 # frozen_string_literal: true
 
 module Minisign
+  # Parse ed25519 signing key from minisign private key
   class PrivateKey
     attr_reader :signature_algorithm, :kdf_algorithm, :cksum_algorithm, :kdf_salt, :kdf_opslimit, :kdf_memlimit,
                 :key_id, :public_key, :secret_key, :checksum
 
-    def initialize(opts, _password = nil)
-      @signature_algorithm = opts[:signature_algorithm]
-      @kdf_algorithm = opts[:kdf_algorithm]
-      @cksum_algorithm = opts[:cksum_algorithm]
-      @kdf_salt = opts[:kdf_salt]
-      @kdf_opslimit = opts[:kdf_opslimit]
-      @kdf_memlimit = opts[:kdf_memlimit]
-      @key_id = opts[:key_id]
-      @secret_key = opts[:secret_key]
-      @public_key = opts[:public_key]
-      @checksum = opts[:checksum]
-    end
-
-    def self.from_file(path, password = nil)
+    # rubocop:disable Metrics/AbcSize
+    def initialize(path, password = nil)
       contents = File.read(path).split("\n")
       bytes = Base64.decode64(contents.last).bytes
-      signature_algorithm = bytes[0..1].pack('U*')
-      kdf_algorithm = bytes[2..3].pack('U*')
-      cksum_algorithm = bytes[4..5].pack('U*')
-      kdf_salt = bytes[6..37]
-      kdf_opslimit = bytes[38..45].pack('V*').unpack('N*').sum
-      kdf_memlimit = bytes[46..53].pack('V*').unpack('N*').sum
+      @signature_algorithm, @kdf_algorithm, @cksum_algorithm =
+        [bytes[0..1], bytes[2..3], bytes[4..5]].map { |a| a.pack('U*') }
+      @kdf_salt = bytes[6..37]
+      @kdf_opslimit = bytes[38..45].pack('V*').unpack('N*').sum
+      @kdf_memlimit = bytes[46..53].pack('V*').unpack('N*').sum
+      kdf_output = derive_key(password, @kdf_salt, @kdf_opslimit, @kdf_memlimit)
+      @key_id, @secret_key, @public_key, @checksum = xor(kdf_output, bytes[54..157])
+    end
+    # rubocop:enable Metrics/AbcSize
 
-      kdf_output = RbNaCl::PasswordHash.scrypt(
+    def derive_key(password, kdf_salt, kdf_opslimit, kdf_memlimit)
+      RbNaCl::PasswordHash.scrypt(
         password,
         kdf_salt.pack('C*'),
         kdf_opslimit,
         kdf_memlimit,
         104
       ).bytes
+    end
 
+    def xor(kdf_output, contents)
       xored = kdf_output.each_with_index.map do |b, i|
-        bytes[54..157][i] ^ b
+        contents[i] ^ b
       end
-
-      key_id = xored[0..7]
-      secret_key = xored[8..39]
-      public_key = xored[40..71]
-      checksum = xored[72..103]
-
-      new({
-            signature_algorithm: signature_algorithm,
-            kdf_algorithm: kdf_algorithm,
-            cksum_algorithm: cksum_algorithm,
-            kdf_salt: kdf_salt,
-            kdf_opslimit: kdf_opslimit,
-            kdf_memlimit: kdf_memlimit,
-            key_id: key_id,
-            secret_key: secret_key,
-            public_key: public_key,
-            checksum: checksum
-          })
+      [xored[0..7], xored[8..39], xored[40..71], xored[72..103]]
     end
   end
 end

spec/minisign/private_key_spec.rb

@@ -4,7 +4,7 @@
 describe Minisign::PrivateKey do
   describe '.from_file' do
     before(:all) do
-      @private_key = Minisign::PrivateKey.from_file('test/minisign.key', 'password')
+      @private_key = Minisign::PrivateKey.new('test/minisign.key', 'password')
     end
 
     it 'parses the signature_algorithm' do
@@ -38,12 +38,12 @@
 
     it 'parses the public key' do
       expect(@private_key.public_key).to eq([108, 35, 192, 26, 47, 128, 233, 165, 133, 38, 242, 5, 76, 55, 135, 40,
-                                             103, 72, 230, 43, 184, 117, 219, 37, 173, 250, 196, 122, 252, 174, 173, 140])
+                                             103, 72, 230, 43, 184, 117, 219, 37, 173, 250, 196, 122, 252, 174, 173, 140]) # rubocop:disable Layout/LineLength
     end
 
     it 'parses the secret key' do
       expect(@private_key.secret_key).to eq([65, 87, 110, 33, 168, 130, 118, 100, 249, 200, 160, 167, 47, 59, 141,
-                                             122, 156, 38, 80, 199, 139, 1, 21, 18, 116, 110, 204, 131, 199, 202, 181, 87])
+                                             122, 156, 38, 80, 199, 139, 1, 21, 18, 116, 110, 204, 131, 199, 202, 181, 87]) # rubocop:disable Layout/LineLength
     end
 
     it 'parses the checksum' do