Implemented an RSA::KeyPair#to_hash method.

lib/rsa/key_pair.rb

@@ -87,6 +87,17 @@ def modulus
     end
     alias_method :n, :modulus
 
+    ##
+    # Returns a hash table representation of this key pair.
+    #
+    # @example
+    #   key_pair.to_hash  #=> {:n => ..., :d => ..., :e => ...}
+    #
+    # @return [Hash]
+    def to_hash
+      {:n => modulus, :d => private_key ? private_key.exponent : nil, :e => public_key ? public_key.exponent : nil}
+    end
+
     ##
     # Encrypts the given `plaintext` using the public key from this key
     # pair.

spec/key_pair_spec.rb

@@ -61,6 +61,20 @@
     end
   end
 
+  context "#to_hash" do
+    it "returns a hash" do
+      @key_pair.to_hash.should be_a(Hash)
+    end
+
+    it "returns a hash with the correct keys" do
+      [:n, :d, :e].each { |key| @key_pair.to_hash.should have_key(key) }
+    end
+
+    it "returns a hash with the correct values" do
+      @key_pair.to_hash.should == {:n => @n, :d => @d, :e => @e}
+    end
+  end
+
   context "#encrypt(Integer)" do
     it "accepts an integer argument" do
       lambda { @key_pair.encrypt(42) }.should_not raise_error(ArgumentError)