Add NIP-01 compliant client code

lib/nostr/key_pair.rb

@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+module Nostr
+  # A pair of public and private keys
+  class KeyPair
+    # 32-bytes hex-encoded private key
+    #
+    # @api public
+    #
+    # @example
+    #   keypair.private_key # => '893c4cc8088924796b41dc788f7e2f746734497010b1a9f005c1faad7074b900'
+    #
+    # @return [String]
+    #
+    attr_reader :private_key
+
+    # 32-bytes hex-encoded public key
+    #
+    # @api public
+    #
+    # @example
+    #   keypair.public_key # => '2d7661527d573cc8e84f665fa971dd969ba51e2526df00c149ff8e40a58f9558'
+    #
+    # @return [String]
+    #
+    attr_reader :public_key
+
+    # Instantiates a key pair
+    #
+    # @api public
+    #
+    # @example
+    #   keypair = Nostr::KeyPair.new(
+    #     private_key: '893c4cc8088924796b41dc788f7e2f746734497010b1a9f005c1faad7074b900',
+    #     public_key: '2d7661527d573cc8e84f665fa971dd969ba51e2526df00c149ff8e40a58f9558',
+    #   )
+    #
+    # @param private_key [String] 32-bytes hex-encoded private key.
+    # @param public_key [String] 32-bytes hex-encoded public key.
+    #
+    def initialize(private_key:, public_key:)
+      @private_key = private_key
+      @public_key = public_key
+    end
+  end
+end