Add support for latest OpenSSL version in ruby >=2.4

thanks to @kangguru

closes #17

lib/epics/client.rb

@@ -102,8 +102,12 @@ def HPB
       exponent = Base64.decode64(node.at_xpath(".//*[local-name() = 'Exponent']").content)
 
       bank   = OpenSSL::PKey::RSA.new
-      bank.n = OpenSSL::BN.new(modulus, 2)
-      bank.e = OpenSSL::BN.new(exponent, 2)
+      if bank.respond_to?(:set_key)
+        bank.set_key(OpenSSL::BN.new(modulus, 2), OpenSSL::BN.new(exponent, 2), nil)
+      else
+        bank.n = OpenSSL::BN.new(modulus, 2)
+        bank.e = OpenSSL::BN.new(exponent, 2)
+      end
 
       self.keys["#{host_id.upcase}.#{type}"] = Epics::Key.new(bank)
     end
@@ -225,7 +229,7 @@ def dump_keys
   end
 
   def cipher
-    @cipher ||= OpenSSL::Cipher::Cipher.new("aes-256-cbc")
+    @cipher ||= OpenSSL::Cipher.new("aes-256-cbc")
   end
 
   def encrypt(data)

lib/epics/generic_upload_request.rb

@@ -10,7 +10,7 @@ def initialize(client, document)
   end
 
   def cipher
-    @cipher ||= OpenSSL::Cipher::Cipher.new("aes-128-cbc")
+    @cipher ||= OpenSSL::Cipher.new("aes-128-cbc")
   end
 
   def digester

lib/epics/response.rb

@@ -84,7 +84,7 @@ def order_data
   end
 
   def cipher
-    cipher = OpenSSL::Cipher::Cipher.new("aes-128-cbc")
+    cipher = OpenSSL::Cipher.new("aes-128-cbc")
 
     cipher.decrypt
     cipher.padding = 0

spec/generic_upload_spec.rb

@@ -18,7 +18,8 @@
   end
 
   describe '#signature_value' do
-    before { allow(OpenSSL::Random).to receive(:random_bytes).and_return(Base64.strict_decode64("7wtROfiX4tyN60cygJUSsHkhzxX1RVJa8vGNYnflvKc=")) }
+    before { allow(OpenSSL::Random).to receive(:random_bytes).with(16).and_return("\x01" * 16) } # fake random_key requires a 16byte lenght but is not used in this test
+    before { allow(OpenSSL::Random).to receive(:random_bytes).with(32).and_return(Base64.strict_decode64("7wtROfiX4tyN60cygJUSsHkhzxX1RVJa8vGNYnflvKc=")) } # digest requires 32 bytes
 
     it 'will be the signed document' do
       expect(subject.signature_value).to eq("BQBMyxGHYoAbbmbMJRFbGrvUNinY15+qeeRLF708VL+tuENnbJMO6xHLWxU1rksOnu4xDzxfua9b3IxIaxLyTTFDuVi6bbu3sBslhIt2frdigo0xBL14KUJQ/pYiMj+2pfNYhtVxzamrnvgPSLNAEn36JykK2d347chT87HlZ7CAGNBS7lJHAzRP1v7Hkc+kKttkkWCpOGk06R6FUCxxVKXmQketMEl/scsMyJ3JtBe/EcjEZdDe5WcqZYUu5ARrfEiAeyutVRZnu17c3nKwkmWl7UqFAwp16cS8IPNL4i5FGCytgKl/kyaoxaE/P1lrGOkHcCTsSR0bAbARhndfdQ==")