diff --git a/app/models/asymmetric_key.rb b/app/models/asymmetric_key.rb
index 9355c31..a4cb5a7 100644
--- a/app/models/asymmetric_key.rb
+++ b/app/models/asymmetric_key.rb
@@ -2,4 +2,72 @@
 
 class AsymmetricKey < ApplicationRecord
   PRIVATE_KEY_CLEAR_DELAY = 1.hour.freeze
+
+  attr_accessor :private_key_pem, :private_key_pem_secret
+
+  ################
+  # Associations #
+  ################
+
+  belongs_to :account, optional: true
+
+  ###############
+  # Validations #
+  ###############
+
+  validates :public_key_pem,
+            presence: true,
+            uniqueness: true
+
+  validates :public_key_der,
+            presence: true,
+            uniqueness: true
+
+  validates :has_password, exclusion: { in: [nil] }
+
+  validates :bits,
+            numericality: {
+              only_integer: true,
+              greater_than: 0,
+            }
+
+  validates :sha1,
+            presence: true,
+            uniqueness: { case_sensitive: false }
+
+  validates :sha256,
+            presence: true,
+            uniqueness: { case_sensitive: false }
+
+  ###########
+  # Methods #
+  ###########
+
+  def encrypt_private_key_pem
+    cipher = OpenSSL::Cipher::AES256.new
+    cipher.encrypt
+
+    self.private_key_pem_iv     = cipher.random_iv.freeze
+    self.private_key_pem_secret = cipher.random_key.freeze
+
+    self.private_key_pem_ciphertext = [
+      cipher.update(private_key_pem),
+      cipher.final,
+    ].join.freeze
+
+    private_key_pem_secret
+  end
+
+  def decrypt_private_key_pem
+    cipher = OpenSSL::Cipher::AES256.new
+    cipher.decrypt
+
+    cipher.iv  = private_key_pem_iv
+    cipher.key = private_key_pem_secret
+
+    self.private_key_pem = [
+      cipher.update(private_key_pem_ciphertext),
+      cipher.final,
+    ].join.freeze
+  end
 end
diff --git a/app/models/rsa_key.rb b/app/models/rsa_key.rb
index cb9ea26..275eebc 100644
--- a/app/models/rsa_key.rb
+++ b/app/models/rsa_key.rb
@@ -1,67 +1,9 @@
 # frozen_string_literal: true
 
 class RSAKey < AsymmetricKey
-  attr_accessor :private_key_pem, :private_key_pem_secret
-
-  ################
-  # Associations #
-  ################
-
-  belongs_to :account, optional: true
-
   ###############
   # Validations #
   ###############
 
-  validates :public_key_pem,
-            presence: true,
-            uniqueness: true
-
-  validates :public_key_der,
-            presence: true,
-            uniqueness: true
-
-  validates :has_password, exclusion: { in: [nil] }
-
   validates :bits, inclusion: { in: [2048, 4096] }
-
-  validates :sha1,
-            presence: true,
-            uniqueness: { case_sensitive: false }
-
-  validates :sha256,
-            presence: true,
-            uniqueness: { case_sensitive: false }
-
-  ###########
-  # Methods #
-  ###########
-
-  def encrypt_private_key_pem
-    cipher = OpenSSL::Cipher::AES256.new
-    cipher.encrypt
-
-    self.private_key_pem_iv     = cipher.random_iv.freeze
-    self.private_key_pem_secret = cipher.random_key.freeze
-
-    self.private_key_pem_ciphertext = [
-      cipher.update(private_key_pem),
-      cipher.final,
-    ].join.freeze
-
-    private_key_pem_secret
-  end
-
-  def decrypt_private_key_pem
-    cipher = OpenSSL::Cipher::AES256.new
-    cipher.decrypt
-
-    cipher.iv  = private_key_pem_iv
-    cipher.key = private_key_pem_secret
-
-    self.private_key_pem = [
-      cipher.update(private_key_pem_ciphertext),
-      cipher.final,
-    ].join.freeze
-  end
 end
diff --git a/spec/models/rsa_key_spec.rb b/spec/models/rsa_key_spec.rb
index 2a4056d..17fc813 100644
--- a/spec/models/rsa_key_spec.rb
+++ b/spec/models/rsa_key_spec.rb
@@ -27,6 +27,13 @@ RSpec.describe RSAKey do
   end
 
   describe '#bits' do
+    it do
+      is_expected.to \
+        validate_numericality_of(:bits)
+        .only_integer
+        .is_greater_than(0)
+    end
+
     it { is_expected.to validate_inclusion_of(:bits).in_array([2048, 4096]) }
   end