diff --git a/app/models/bill_signature.rb b/app/models/bill_signature.rb
new file mode 100644
index 000000000..cef20c232
--- /dev/null
+++ b/app/models/bill_signature.rb
@@ -0,0 +1,84 @@
+class BillSignature < ApplicationRecord
+  has_many :dossier_operation_logs
+
+  has_one_attached :serialized
+  has_one_attached :signature
+
+  validate :check_bill_digest
+  validate :check_serialized_bill_contents
+  validate :check_signature_contents
+
+  def self.build_with_operations(operations, day)
+    bill = new(dossier_operation_logs: operations)
+
+    bill.serialize_operations(day)
+
+    bill
+  end
+
+  def serialize_operations(day)
+    self.serialized.attach(
+      io: StringIO.new(operations_bill_json),
+      filename: "demarches-simplifiees-operations-#{day.to_date.iso8601}.json",
+      content_type: 'application/json',
+      metadata: { virus_scan_result: ActiveStorage::VirusScanner::SAFE }
+    )
+
+    self.digest = operations_bill_digest
+  end
+
+  def operations_bill
+    dossier_operation_logs.map { |op| [op.id.to_s, op.digest] }.to_h
+  end
+
+  def operations_bill_json
+    operations_bill.to_json
+  end
+
+  def operations_bill_digest
+    Digest::SHA256.hexdigest(operations_bill_json)
+  end
+
+  def set_signature(signature, day)
+    self.signature.attach(
+      io: StringIO.new(signature),
+      filename: "demarches-simplifiees-signature-#{day.to_date.iso8601}.der",
+      content_type: 'application/x-x509-ca-cert'
+    )
+  end
+
+  # Validations
+  def check_bill_digest
+    if self.digest != self.operations_bill_digest
+      errors.add(:digest)
+    end
+  end
+
+  def check_serialized_bill_contents
+    if !self.serialized.attached?
+      errors.add(:serialized, :blank)
+      return
+    end
+
+    if JSON.parse(self.serialized.download) != self.operations_bill
+      errors.add(:serialized)
+    end
+  end
+
+  def check_signature_contents
+    if !self.signature.attached?
+      errors.add(:signature, :blank)
+      return
+    end
+
+    timestamp_signature_date = ASN1::Timestamp.signature_time(self.signature.download)
+    if timestamp_signature_date > Time.zone.now
+      errors.add(:signature, :invalid_date)
+    end
+
+    timestamp_signed_digest = ASN1::Timestamp.signed_digest(self.signature.download)
+    if timestamp_signed_digest != self.digest
+      errors.add(:signature)
+    end
+  end
+end
diff --git a/app/models/dossier_operation_log.rb b/app/models/dossier_operation_log.rb
index e517dcb36..a66492ace 100644
--- a/app/models/dossier_operation_log.rb
+++ b/app/models/dossier_operation_log.rb
@@ -12,6 +12,7 @@ class DossierOperationLog < ApplicationRecord
 
   belongs_to :dossier
   has_one_attached :serialized
+  belongs_to :bill_signature, optional: true
 
   def self.create_and_serialize(params)
     dossier = params.fetch(:dossier)
diff --git a/config/locales/models/bill_signature/fr.yml b/config/locales/models/bill_signature/fr.yml
new file mode 100644
index 000000000..8e7a1c744
--- /dev/null
+++ b/config/locales/models/bill_signature/fr.yml
@@ -0,0 +1,27 @@
+fr:
+  activerecord:
+    attributes:
+      bill_signature:
+        dossier_operation_logs:
+          one: opération
+          other: opérations
+        digest: empreinte
+        serialized: liasse
+        signature: signature
+    errors:
+      models:
+        bill_signature:
+          attributes:
+            digest:
+              invalid: 'ne correspond pas à la liasse'
+            serialized:
+              blank: 'doit être rempli'
+              invalid: 'ne correspond pas aux opérations'
+            signature:
+              blank: 'doit être rempli'
+              invalid: 'ne correspond pas à l’empreinte'
+              invalid_date: 'ne doit pas être dans le futur'
+    models:
+      bill_signature:
+        one: Horodatage
+        other: Horodatages
diff --git a/db/migrate/20190616141702_create_bill_signature.rb b/db/migrate/20190616141702_create_bill_signature.rb
new file mode 100644
index 000000000..95b0b9a2e
--- /dev/null
+++ b/db/migrate/20190616141702_create_bill_signature.rb
@@ -0,0 +1,10 @@
+class CreateBillSignature < ActiveRecord::Migration[5.2]
+  def change
+    create_table :bill_signatures do |t|
+      t.string :digest
+      t.timestamps
+    end
+
+    add_reference :dossier_operation_logs, :bill_signature, foreign_key: true
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 0a29eae67..f44e8df90 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2019_06_07_124156) do
+ActiveRecord::Schema.define(version: 2019_06_16_141702) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -145,6 +145,12 @@ ActiveRecord::Schema.define(version: 2019_06_07_124156) do
     t.index ["gestionnaire_id"], name: "index_avis_on_gestionnaire_id"
   end
 
+  create_table "bill_signatures", force: :cascade do |t|
+    t.string "digest"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+  end
+
   create_table "champs", id: :serial, force: :cascade do |t|
     t.string "value"
     t.integer "type_de_champ_id"
@@ -224,7 +230,9 @@ ActiveRecord::Schema.define(version: 2019_06_07_124156) do
     t.datetime "keep_until"
     t.datetime "executed_at"
     t.text "digest"
+    t.bigint "bill_signature_id"
     t.index ["administration_id"], name: "index_dossier_operation_logs_on_administration_id"
+    t.index ["bill_signature_id"], name: "index_dossier_operation_logs_on_bill_signature_id"
     t.index ["dossier_id"], name: "index_dossier_operation_logs_on_dossier_id"
     t.index ["gestionnaire_id"], name: "index_dossier_operation_logs_on_gestionnaire_id"
     t.index ["keep_until"], name: "index_dossier_operation_logs_on_keep_until"
@@ -617,6 +625,7 @@ ActiveRecord::Schema.define(version: 2019_06_07_124156) do
   add_foreign_key "closed_mails", "procedures"
   add_foreign_key "commentaires", "dossiers"
   add_foreign_key "dossier_operation_logs", "administrations"
+  add_foreign_key "dossier_operation_logs", "bill_signatures"
   add_foreign_key "dossier_operation_logs", "dossiers"
   add_foreign_key "dossier_operation_logs", "gestionnaires"
   add_foreign_key "dossiers", "users"
diff --git a/spec/factories/bill_signature.rb b/spec/factories/bill_signature.rb
new file mode 100644
index 000000000..363aafb8f
--- /dev/null
+++ b/spec/factories/bill_signature.rb
@@ -0,0 +1,6 @@
+FactoryBot.define do
+  factory :bill_signature do
+    serialized { Rack::Test::UploadedFile.new("./spec/fixtures/files/bill_signature/serialized.json", 'application/json') }
+    signature { Rack::Test::UploadedFile.new("./spec/fixtures/files/bill_signature/signature.der", 'application/x-x509-ca-cert') }
+  end
+end
diff --git a/spec/factories/dossier_operation_log.rb b/spec/factories/dossier_operation_log.rb
new file mode 100644
index 000000000..ff6a80a53
--- /dev/null
+++ b/spec/factories/dossier_operation_log.rb
@@ -0,0 +1,5 @@
+FactoryBot.define do
+  factory :dossier_operation_log do
+    operation { :passer_en_instruction }
+  end
+end
diff --git a/spec/fixtures/files/bill_signature/serialized.json b/spec/fixtures/files/bill_signature/serialized.json
new file mode 100644
index 000000000..87852f06f
--- /dev/null
+++ b/spec/fixtures/files/bill_signature/serialized.json
@@ -0,0 +1 @@
+{"dossier1": "hash1", "dossier2": "hash2"}
diff --git a/spec/models/bill_signature_spec.rb b/spec/models/bill_signature_spec.rb
new file mode 100644
index 000000000..1456a97e4
--- /dev/null
+++ b/spec/models/bill_signature_spec.rb
@@ -0,0 +1,158 @@
+require 'rails_helper'
+
+RSpec.describe BillSignature, type: :model do
+  describe 'validations' do
+    describe 'check_bill_digest' do
+      before do
+        subject.dossier_operation_logs = dossier_operation_logs
+        subject.digest = digest
+        subject.valid?
+      end
+
+      context 'no operations' do
+        let(:dossier_operation_logs) { [] }
+
+        context 'correct digest' do
+          let(:digest) { Digest::SHA256.hexdigest('{}') }
+
+          it { expect(subject.errors.details[:digest]).to be_empty }
+        end
+
+        context 'bad digest' do
+          let(:digest) { 'baadf00d' }
+
+          it { expect(subject.errors.details[:digest]).to eq [error: :invalid] }
+        end
+      end
+
+      context 'operations set, good digest' do
+        let(:dossier_operation_logs) { [build(:dossier_operation_log, id: '1234', digest: 'abcd')] }
+
+        context 'correct digest' do
+          let(:digest) { Digest::SHA256.hexdigest('{"1234":"abcd"}') }
+
+          it { expect(subject.errors.details[:digest]).to be_empty }
+        end
+
+        context 'bad digest' do
+          let(:digest) { 'baadf00d' }
+
+          it { expect(subject.errors.details[:digest]).to eq [error: :invalid] }
+        end
+      end
+    end
+
+    describe 'check_serialized_bill_contents' do
+      before do
+        subject.dossier_operation_logs = dossier_operation_logs
+        subject.serialized.attach(io: StringIO.new(serialized), filename: 'file') if serialized.present?
+        subject.valid?
+      end
+
+      context 'no operations' do
+        let(:dossier_operation_logs) { [] }
+        let(:serialized) { '{}' }
+
+        it { expect(subject.errors.details[:serialized]).to be_empty }
+      end
+
+      context 'operations set' do
+        let(:dossier_operation_logs) { [build(:dossier_operation_log, id: '1234', digest: 'abcd')] }
+        let(:serialized) { '{"1234":"abcd"}' }
+
+        it { expect(subject.errors.details[:serialized]).to be_empty }
+      end
+
+      context 'serialized not set' do
+        let(:dossier_operation_logs) { [] }
+        let(:serialized) { nil }
+
+        it { expect(subject.errors.details[:serialized]).to eq [error: :blank] }
+      end
+    end
+
+    describe 'check_signature_contents' do
+      before do
+        subject.signature.attach(io: StringIO.new(signature), filename: 'file') if signature.present?
+        allow(ASN1::Timestamp).to receive(:signature_time).and_return(signature_time)
+        allow(ASN1::Timestamp).to receive(:signed_digest).and_return(signed_digest)
+        subject.digest = digest
+        subject.valid?
+      end
+
+      context 'correct signature' do
+        let(:signature) { 'signature' }
+        let(:signature_time) { 1.day.ago }
+        let(:digest) { 'abcd' }
+        let(:signed_digest) { 'abcd' }
+
+        it { expect(subject.errors.details[:signature]).to be_empty }
+      end
+
+      context 'signature not set' do
+        let(:signature) { nil }
+        let(:signature_time) { 1.day.ago }
+        let(:digest) { 'abcd' }
+        let(:signed_digest) { 'abcd' }
+
+        it { expect(subject.errors.details[:signature]).to eq [error: :blank] }
+      end
+
+      context 'wrong signature time' do
+        let(:signature) { 'signature' }
+        let(:signature_time) { 1.day.from_now }
+        let(:digest) { 'abcd' }
+        let(:signed_digest) { 'abcd' }
+
+        it { expect(subject.errors.details[:signature]).to eq [error: :invalid_date] }
+      end
+
+      context 'wrong signature digest' do
+        let(:signature) { 'signature' }
+        let(:signature_time) { 1.day.ago }
+        let(:digest) { 'abcd' }
+        let(:signed_digest) { 'dcba' }
+
+        it { expect(subject.errors.details[:signature]).to eq [error: :invalid] }
+      end
+    end
+  end
+
+  describe '.build_with_operations' do
+    subject { described_class.build_with_operations(dossier_operation_logs, Date.new(1871, 03, 18)) }
+
+    context 'no operations' do
+      let(:dossier_operation_logs) { [] }
+
+      it { expect(subject.operations_bill).to eq({}) }
+      it { expect(subject.digest).to eq(Digest::SHA256.hexdigest('{}')) }
+      it { expect(subject.serialized.download).to eq('{}') }
+      it { expect(subject.serialized.filename).to eq('demarches-simplifiees-operations-1871-03-18.json') }
+    end
+
+    context 'one operation' do
+      let(:dossier_operation_logs) do
+        [build(:dossier_operation_log, id: '1234', digest: 'abcd')]
+      end
+
+      it { expect(subject.operations_bill).to eq({ '1234' => 'abcd' }) }
+      it { expect(subject.digest).to eq(Digest::SHA256.hexdigest('{"1234":"abcd"}')) }
+      it { expect(subject.serialized.download).to eq('{"1234":"abcd"}') }
+      it { expect(subject.serialized.filename).to eq('demarches-simplifiees-operations-1871-03-18.json') }
+    end
+
+    context 'several operations' do
+      let(:dossier_operation_logs) do
+        [
+          build(:dossier_operation_log, id: '1234', digest: 'abcd'),
+          build(:dossier_operation_log, id: '5678', digest: 'dcba')
+        ]
+      end
+
+      it { expect(subject.operations_bill).to eq({ '1234' => 'abcd', '5678' => 'dcba' }) }
+      it { expect(subject.digest).to eq(Digest::SHA256.hexdigest('{"1234":"abcd","5678":"dcba"}')) }
+      it { expect(subject.serialized.download).to eq('{"1234":"abcd","5678":"dcba"}') }
+      it { expect(subject.serialized.filename).to eq('demarches-simplifiees-operations-1871-03-18.json') }
+    end
+  end
+end