diff --git a/lib/diaspora_federation/entities/reshare.rb b/lib/diaspora_federation/entities/reshare.rb
index 2ccc577..96ae593 100644
--- a/lib/diaspora_federation/entities/reshare.rb
+++ b/lib/diaspora_federation/entities/reshare.rb
@@ -16,7 +16,7 @@ module DiasporaFederation
       #   Guid of the original post
       #   @see StatusMessage#guid
       #   @return [String] root guid
-      property :root_guid, :string
+      property :root_guid, :string, optional: true
 
       # @!attribute [r] public
       #   Has no meaning at the moment
diff --git a/lib/diaspora_federation/validators/photo_validator.rb b/lib/diaspora_federation/validators/photo_validator.rb
index 4dbc2ca..48e0d73 100644
--- a/lib/diaspora_federation/validators/photo_validator.rb
+++ b/lib/diaspora_federation/validators/photo_validator.rb
@@ -14,7 +14,7 @@ module DiasporaFederation
 
       rule :remote_photo_name, :not_empty
 
-      rule :status_message_guid, guid: {nilable: true}
+      rule :status_message_guid, :guid
 
       rule :text, length: {maximum: 65_535}
 
diff --git a/lib/diaspora_federation/validators/reshare_validator.rb b/lib/diaspora_federation/validators/reshare_validator.rb
index 627d443..db8858d 100644
--- a/lib/diaspora_federation/validators/reshare_validator.rb
+++ b/lib/diaspora_federation/validators/reshare_validator.rb
@@ -6,7 +6,7 @@ module DiasporaFederation
 
       rule :root_author, :diaspora_id
 
-      rule :root_guid, guid: {nilable: true}
+      rule :root_guid, :guid
 
       rule :author, %i[not_empty diaspora_id]
 
diff --git a/lib/diaspora_federation/validators/rules/guid.rb b/lib/diaspora_federation/validators/rules/guid.rb
index e006e8d..1405e1c 100644
--- a/lib/diaspora_federation/validators/rules/guid.rb
+++ b/lib/diaspora_federation/validators/rules/guid.rb
@@ -7,21 +7,6 @@ module Validation
     # * Numbers: 0-9
     # * Special chars: '-', '_', '@', '.' and ':'
     class Guid
-      # This rule can have a +nilable+ param.
-      # @return [Hash] params
-      attr_reader :params
-
-      # Creates a new rule for guid validation
-      # @param [Hash] params
-      # @option params [Boolean] :nilable guid allowed to be nil
-      def initialize(params={})
-        if params.include?(:nilable) && !params[:nilable].is_a?(TrueClass) && !params[:nilable].is_a?(FalseClass)
-          raise ArgumentError, ":nilable needs to be a boolean"
-        end
-
-        @params = params
-      end
-
       # The error key for this rule
       # @return [Symbol] error key
       def error_key
@@ -30,7 +15,13 @@ module Validation
 
       # Determines if value is a valid +GUID+
       def valid_value?(value)
-        params[:nilable] && value.nil? || value.is_a?(String) && value.downcase =~ /\A[0-9a-z\-_@.:]{16,255}\z/
+        value.is_a?(String) && value.downcase =~ /\A[0-9a-z\-_@.:]{16,255}\z/
+      end
+
+      # This rule has no params.
+      # @return [Hash] params
+      def params
+        {}
       end
     end
   end
diff --git a/spec/lib/diaspora_federation/validators/rules/guid_spec.rb b/spec/lib/diaspora_federation/validators/rules/guid_spec.rb
index 25d87dc..d8954dc 100644
--- a/spec/lib/diaspora_federation/validators/rules/guid_spec.rb
+++ b/spec/lib/diaspora_federation/validators/rules/guid_spec.rb
@@ -1,25 +1,9 @@
 describe Validation::Rule::Guid do
-  it "allows a nilable parameter" do
+  it "will not accept parameters" do
     validator = Validation::Validator.new({})
     expect {
-      validator.rule(:guid, guid: {nilable: false})
-    }.not_to raise_error
-  end
-
-  it "doesn't require a nilable parameter" do
-    validator = Validation::Validator.new({})
-    expect {
-      validator.rule(:guid, :guid)
-    }.not_to raise_error
-  end
-
-  it "requires a boolean as parameter" do
-    validator = Validation::Validator.new({})
-    [nil, "", 42, 5.5].each do |val|
-      expect {
-        validator.rule(:guid, guid: {nilable: val})
-      }.to raise_error ArgumentError, ":nilable needs to be a boolean"
-    end
+      validator.rule(:guid, guid: {param: true})
+    }.to raise_error ArgumentError
   end
 
   it "has an error key" do
@@ -45,14 +29,6 @@ describe Validation::Rule::Guid do
       expect(validator.errors).to be_empty
     end
 
-    it "validates a nil guid if nilable is true" do
-      validator = Validation::Validator.new(OpenStruct.new(guid: nil))
-      validator.rule(:guid, guid: {nilable: true})
-
-      expect(validator).to be_valid
-      expect(validator.errors).to be_empty
-    end
-
     it "fails if the string is too short" do
       validator = Validation::Validator.new(OpenStruct.new(guid: "012345"))
       validator.rule(:guid, :guid)
@@ -77,14 +53,6 @@ describe Validation::Rule::Guid do
       expect(validator.errors).to include(:guid)
     end
 
-    it "fails if the string contains invalid chars if nilable is true" do
-      validator = Validation::Validator.new(OpenStruct.new(guid: "ghijklmnopqrstuvwxyz++"))
-      validator.rule(:guid, guid: {nilable: true})
-
-      expect(validator).not_to be_valid
-      expect(validator.errors).to include(:guid)
-    end
-
     it "fails if the string is empty" do
       [nil, ""].each do |val|
         validator = Validation::Validator.new(OpenStruct.new(guid: val))