diff --git a/app/controllers/concerns/idv_step_concern.rb b/app/controllers/concerns/idv_step_concern.rb
index f6a6e4a1bc0..d1f47168e7f 100644
--- a/app/controllers/concerns/idv_step_concern.rb
+++ b/app/controllers/concerns/idv_step_concern.rb
@@ -38,7 +38,7 @@ def redirect_for_mail_only
   end
 
   def pii_from_doc
-    flow_session['pii_from_doc']
+    flow_session[:pii_from_doc]
   end
 
   def pii_from_user
diff --git a/app/controllers/idv/address_controller.rb b/app/controllers/idv/address_controller.rb
index 12d04526022..5e35d7ad7b0 100644
--- a/app/controllers/idv/address_controller.rb
+++ b/app/controllers/idv/address_controller.rb
@@ -29,7 +29,7 @@ def idv_form
 
     def success
       profile_params.each do |key, value|
-        flow_session['pii_from_doc'][key] = value
+        flow_session[:pii_from_doc][key] = value
       end
       redirect_to idv_verify_info_url
     end
diff --git a/app/controllers/idv/document_capture_controller.rb b/app/controllers/idv/document_capture_controller.rb
index b7ae2db42da..a544879732a 100644
--- a/app/controllers/idv/document_capture_controller.rb
+++ b/app/controllers/idv/document_capture_controller.rb
@@ -57,8 +57,7 @@ def confirm_hybrid_handoff_complete
     def confirm_document_capture_needed
       return if idv_session.redo_document_capture
 
-      pii = flow_session['pii_from_doc'] # hash with indifferent access
-      return if pii.blank? && !idv_session.verify_info_step_complete?
+      return if pii_from_doc.blank? && !idv_session.verify_info_step_complete?
 
       redirect_to idv_ssn_url
     end
diff --git a/app/controllers/idv/link_sent_controller.rb b/app/controllers/idv/link_sent_controller.rb
index d5e7a760321..350d945d8a1 100644
--- a/app/controllers/idv/link_sent_controller.rb
+++ b/app/controllers/idv/link_sent_controller.rb
@@ -48,8 +48,7 @@ def confirm_hybrid_handoff_complete
     def confirm_document_capture_needed
       return if idv_session.redo_document_capture
 
-      pii = flow_session['pii_from_doc'] # hash with indifferent access
-      return if pii.blank? && !idv_session.verify_info_step_complete?
+      return if pii_from_doc.blank? && !idv_session.verify_info_step_complete?
 
       redirect_to idv_ssn_url
     end
diff --git a/app/controllers/idv/session_errors_controller.rb b/app/controllers/idv/session_errors_controller.rb
index 29137df4b29..12bbf1b65f2 100644
--- a/app/controllers/idv/session_errors_controller.rb
+++ b/app/controllers/idv/session_errors_controller.rb
@@ -60,7 +60,7 @@ def rate_limited
     private
 
     def ssn_from_doc
-      user_session&.dig('idv/doc_auth', 'pii_from_doc', 'ssn')
+      user_session&.dig('idv/doc_auth', :pii_from_doc, 'ssn')
     end
 
     def confirm_two_factor_authenticated_or_user_id_in_session
diff --git a/app/controllers/idv/ssn_controller.rb b/app/controllers/idv/ssn_controller.rb
index bc119ae292b..ca517ce946d 100644
--- a/app/controllers/idv/ssn_controller.rb
+++ b/app/controllers/idv/ssn_controller.rb
@@ -38,7 +38,7 @@ def update
       )
 
       if form_response.success?
-        flow_session['pii_from_doc'][:ssn] = params[:doc_auth][:ssn]
+        flow_session[:pii_from_doc][:ssn] = params[:doc_auth][:ssn]
         idv_session.invalidate_steps_after_ssn!
         redirect_to next_url
       else
diff --git a/app/controllers/idv/verify_info_controller.rb b/app/controllers/idv/verify_info_controller.rb
index 87aa36bf3e3..6bad7dbec80 100644
--- a/app/controllers/idv/verify_info_controller.rb
+++ b/app/controllers/idv/verify_info_controller.rb
@@ -56,7 +56,7 @@ def analytics_arguments
 
     # copied from verify_step
     def pii
-      @pii = flow_session[:pii_from_doc]
+      @pii = pii_from_doc
     end
   end
 end
diff --git a/app/forms/idv/ssn_format_form.rb b/app/forms/idv/ssn_format_form.rb
index 2e3e8617d1a..bdd78be1e39 100644
--- a/app/forms/idv/ssn_format_form.rb
+++ b/app/forms/idv/ssn_format_form.rb
@@ -13,7 +13,7 @@ def self.model_name
 
     def initialize(user, flow_session = {})
       @user = user
-      @ssn = flow_session.dig('pii_from_doc', :ssn)
+      @ssn = flow_session.dig(:pii_from_doc, :ssn)
       @updating_ssn = ssn.present?
     end
 
diff --git a/spec/controllers/idv/address_controller_spec.rb b/spec/controllers/idv/address_controller_spec.rb
index a7f1a57ccf7..53df0614f6d 100644
--- a/spec/controllers/idv/address_controller_spec.rb
+++ b/spec/controllers/idv/address_controller_spec.rb
@@ -10,9 +10,7 @@
   let(:pii_from_doc) { Idp::Constants::MOCK_IDV_APPLICANT_WITH_SSN.stringify_keys }
 
   let(:flow_session) do
-    {
-      'pii_from_doc' => pii_from_doc,
-    }
+    { pii_from_doc: pii_from_doc }
   end
 
   before do
@@ -60,7 +58,7 @@
     it 'updates pii_from_doc' do
       expect do
         put :update, params: params
-      end.to change { flow_session['pii_from_doc'] }.to eql(
+      end.to change { flow_session[:pii_from_doc] }.to eql(
         pii_from_doc.merge(
           {
             'address1' => '1234 Main St',
diff --git a/spec/controllers/idv/document_capture_controller_spec.rb b/spec/controllers/idv/document_capture_controller_spec.rb
index 1c1bde51257..28fa9d637b2 100644
--- a/spec/controllers/idv/document_capture_controller_spec.rb
+++ b/spec/controllers/idv/document_capture_controller_spec.rb
@@ -113,7 +113,7 @@
 
     context 'with pii in session' do
       it 'redirects to ssn step' do
-        flow_session['pii_from_doc'] = Idp::Constants::MOCK_IDV_APPLICANT
+        flow_session[:pii_from_doc] = Idp::Constants::MOCK_IDV_APPLICANT
         get :show
 
         expect(response).to redirect_to(idv_ssn_url)
diff --git a/spec/controllers/idv/link_sent_controller_spec.rb b/spec/controllers/idv/link_sent_controller_spec.rb
index 4ee86a96336..f201ca8a477 100644
--- a/spec/controllers/idv/link_sent_controller_spec.rb
+++ b/spec/controllers/idv/link_sent_controller_spec.rb
@@ -99,7 +99,7 @@
 
     context 'with pii in session' do
       it 'redirects to ssn step' do
-        flow_session['pii_from_doc'] = Idp::Constants::MOCK_IDV_APPLICANT
+        flow_session[:pii_from_doc] = Idp::Constants::MOCK_IDV_APPLICANT
         get :show
 
         expect(response).to redirect_to(idv_ssn_url)
diff --git a/spec/controllers/idv/session_errors_controller_spec.rb b/spec/controllers/idv/session_errors_controller_spec.rb
index 8c5bcdd0d54..dccf65ae2db 100644
--- a/spec/controllers/idv/session_errors_controller_spec.rb
+++ b/spec/controllers/idv/session_errors_controller_spec.rb
@@ -284,7 +284,7 @@
           rate_limit_type: :proof_ssn,
           target: Pii::Fingerprinter.fingerprint(ssn),
         ).increment_to_limited!
-        controller.user_session['idv/doc_auth'] = { 'pii_from_doc' => { 'ssn' => ssn } }
+        controller.user_session['idv/doc_auth'] = { pii_from_doc: { 'ssn' => ssn } }
       end
 
       it 'assigns expiration time' do
diff --git a/spec/controllers/idv/ssn_controller_spec.rb b/spec/controllers/idv/ssn_controller_spec.rb
index d12cbd0962a..d42f0a3431a 100644
--- a/spec/controllers/idv/ssn_controller_spec.rb
+++ b/spec/controllers/idv/ssn_controller_spec.rb
@@ -4,9 +4,7 @@
   include IdvHelper
 
   let(:flow_session) do
-    { 'document_capture_session_uuid' => 'fd14e181-6fb1-4cdc-92e0-ef66dad0df4e',
-      'pii_from_doc' => Idp::Constants::MOCK_IDV_APPLICANT.dup,
-      :threatmetrix_session_id => 'c90ae7a5-6629-4e77-b97c-f1987c2df7d0' }
+    { pii_from_doc: Idp::Constants::MOCK_IDV_APPLICANT.dup }
   end
 
   let(:ssn) { Idp::Constants::MOCK_IDV_APPLICANT_WITH_SSN[:ssn] }
@@ -95,7 +93,7 @@
     context 'with an ssn in session' do
       let(:referer) { idv_document_capture_url }
       before do
-        flow_session['pii_from_doc'][:ssn] = ssn
+        flow_session[:pii_from_doc][:ssn] = ssn
         request.env['HTTP_REFERER'] = referer
       end
 
@@ -158,12 +156,12 @@
       it 'merges ssn into pii session value' do
         put :update, params: params
 
-        expect(flow_session['pii_from_doc'][:ssn]).to eq(ssn)
+        expect(flow_session[:pii_from_doc][:ssn]).to eq(ssn)
       end
 
       context 'with a Puerto Rico address' do
         it 'redirects to address controller after user enters their SSN' do
-          flow_session['pii_from_doc'][:state] = 'PR'
+          flow_session[:pii_from_doc][:state] = 'PR'
 
           put :update, params: params
 
@@ -171,8 +169,8 @@
         end
 
         it 'redirects to the verify info controller if a user is updating their SSN' do
-          flow_session['pii_from_doc'][:ssn] = ssn
-          flow_session['pii_from_doc'][:state] = 'PR'
+          flow_session[:pii_from_doc][:ssn] = ssn
+          flow_session[:pii_from_doc][:state] = 'PR'
 
           put :update, params: params
 
@@ -198,7 +196,7 @@
       end
 
       it 'does not change threatmetrix_session_id when updating ssn' do
-        flow_session['pii_from_doc'][:ssn] = ssn
+        flow_session[:pii_from_doc][:ssn] = ssn
         put :update, params: params
         session_id = subject.idv_session.threatmetrix_session_id
         subject.threatmetrix_view_variables
@@ -239,7 +237,7 @@
     context 'when pii_from_doc is not present' do
       before do
         subject.idv_session.flow_path = 'standard'
-        flow_session.delete('pii_from_doc')
+        flow_session.delete(:pii_from_doc)
       end
 
       it 'redirects to DocumentCaptureController on standard flow' do
diff --git a/spec/controllers/idv/verify_info_controller_spec.rb b/spec/controllers/idv/verify_info_controller_spec.rb
index a1f41d940d9..3ea43bbf8c1 100644
--- a/spec/controllers/idv/verify_info_controller_spec.rb
+++ b/spec/controllers/idv/verify_info_controller_spec.rb
@@ -4,10 +4,7 @@
   include IdvHelper
 
   let(:flow_session) do
-    { 'error_message' => nil,
-      'document_capture_session_uuid' => 'fd14e181-6fb1-4cdc-92e0-ef66dad0df4e',
-      :pii_from_doc => Idp::Constants::MOCK_IDV_APPLICANT_WITH_SSN.dup,
-      'threatmetrix_session_id' => 'c90ae7a5-6629-4e77-b97c-f1987c2df7d0' }
+    { pii_from_doc: Idp::Constants::MOCK_IDV_APPLICANT_WITH_SSN.dup }
   end
 
   let(:user) { create(:user) }
diff --git a/spec/forms/idv/ssn_format_form_spec.rb b/spec/forms/idv/ssn_format_form_spec.rb
index b0855ce7581..8c2b282ea6c 100644
--- a/spec/forms/idv/ssn_format_form_spec.rb
+++ b/spec/forms/idv/ssn_format_form_spec.rb
@@ -48,7 +48,7 @@
     end
 
     context 'when there is an SSN in the pii_from_doc hash' do
-      let(:flow_session) { { 'pii_from_doc' => { ssn: '900-12-3456' } } }
+      let(:flow_session) { { pii_from_doc: { ssn: '900-12-3456' } } }
 
       it { expect(subject.updating_ssn?).to eq(true) }
     end