[IMP] account: Add restrict mode and normal mode for account move.

This commit deletes account_cancel module and squash it into account.
The 'update_posted' field is changed by 'restrict_mode_hash_table' field.

If 'restrict_mode_hash_table' is true, you have a hash chain on your account journal.
These hash chains prove the inalterability of your accounting.

l10n_fr_certification module is deleted and all hashing method are moved in account module.
Now, you can download a PDF report about your inalterability in the company settings.

If you have l10n_fr or l10n_post_cert installed you have more information on this report
like the inalterability of pos orders, etc.

Task ID: 2039160

17 files changed, 420 insertions, 89 deletions

diff --git a/addons/account/__manifest__.py b/addons/account/__manifest__.py
index 1670fd3bc62..f7544acca7b 100644
--- a/addons/account/__manifest__.py
+++ b/addons/account/__manifest__.py
@@ -61,7 +61,8 @@ You could use this simplified accounting in case you work with an (external) acc
         'views/digest_views.xml',
         'wizard/account_invoice_send_views.xml',
         'views/account_tax_report_views.xml',
-        'views/report_statement.xml'
+        'views/report_statement.xml',
+        'report/account_hash_integrity_templates.xml'
     ],
     'demo': [
         'demo/account_demo.xml',
diff --git a/addons/account/models/account.py b/addons/account/models/account.py
index fb8c6d9cb2c..b3d45dc26f6 100644
--- a/addons/account/models/account.py
+++ b/addons/account/models/account.py
@@ -638,8 +638,8 @@ class AccountJournal(models.Model):
         ondelete='restrict')
     default_debit_account_id = fields.Many2one('account.account', string='Default Debit Account',
         domain="[('deprecated', '=', False), ('company_id', '=', company_id)]", help="It acts as a default account for debit amount", ondelete='restrict')
-    update_posted = fields.Boolean(string='Allow Cancelling Entries',
-        help="Check this box if you want to allow the cancellation the entries related to this journal or of the invoice related to this journal")
+    restrict_mode_hash_table = fields.Boolean(string="Lock Posted Entries with Hash",
+        help="If ticked, the accounting entry or invoice receives a hash as soon as it is posted and cannot be modified anymore.")
     sequence_id = fields.Many2one('ir.sequence', string='Entry Sequence',
         help="This field contains the information related to the numbering of the journal entries of this journal.", required=True, copy=False)
     refund_sequence_id = fields.Many2one('ir.sequence', string='Credit Note Entry Sequence',
@@ -694,6 +694,8 @@ class AccountJournal(models.Model):
 
     journal_group_ids = fields.Many2many('account.journal.group', domain="[('company_id', '=', company_id)]", string="Journal Groups")
 
+    secure_sequence_id = fields.Many2one('ir.sequence', help='Sequence to use to ensure the securisation of data', readonly=True, copy=False)
+
     _sql_constraints = [
         ('code_company_uniq', 'unique (code, name, company_id)', 'The code and name of the journal must be unique per company !'),
     ]
@@ -860,6 +862,11 @@ class AccountJournal(models.Model):
                         raise UserError(_("The partners of the journal's company and the related bank account mismatch."))
             if 'alias_name' in vals:
                 journal._update_mail_alias(vals)
+            if 'restrict_mode_hash_table' in vals and not vals.get('restrict_mode_hash_table'):
+                journal_entry = self.env['account.move'].search([('journal_id', '=', self.id), ('state', '=', 'posted'), ('secure_sequence_number', '!=', 0)], limit=1)
+                if len(journal_entry) > 0:
+                    field_string = self._fields['restrict_mode_hash_table'].get_description(self.env)['string']
+                    raise UserError(_("You cannot modify the field %s of a journal that already has accounting entries.") % field_string)
         result = super(AccountJournal, self).write(vals)
 
         # Create the bank_account_id if necessary
@@ -882,6 +889,10 @@ class AccountJournal(models.Model):
             pending_payments = draft_moves.mapped('line_ids.payment_id')
             pending_payments.mapped('move_line_ids.move_id').post()
             pending_payments.mapped('reconciled_invoice_ids').filtered(lambda x: x.state == 'in_payment').write({'state': 'paid'})
+        for record in self:
+            if record.restrict_mode_hash_table and not record.secure_sequence_id:
+                record._create_secure_sequence(['secure_sequence_id'])
+
         return result
 
     @api.model
@@ -1073,6 +1084,28 @@ class AccountJournal(models.Model):
             action_vals['view_mode'] = 'tree,form'
         return action_vals
 
+    def _create_secure_sequence(self, sequence_fields):
+        """This function creates a no_gap sequence on each journal in self that will ensure
+        a unique number is given to all posted account.move in such a way that we can always
+        find the previous move of a journal entry on a specific journal.
+        """
+        for journal in self:
+            vals_write = {}
+            for seq_field in sequence_fields:
+                if not journal[seq_field]:
+                    vals = {
+                        'name': _('Securisation of %s - %s') % (seq_field, journal.name),
+                        'code': 'SECUR%s-%s' % (journal.id, seq_field),
+                        'implementation': 'no_gap',
+                        'prefix': '',
+                        'suffix': '',
+                        'padding': 0,
+                        'company_id': journal.company_id.id}
+                    seq = self.env['ir.sequence'].create(vals)
+                    vals_write[seq_field] = seq.id
+            if vals_write:
+                journal.write(vals_write)
+
 
 class ResPartnerBank(models.Model):
     _inherit = "res.partner.bank"
diff --git a/addons/account/models/account_bank_statement.py b/addons/account/models/account_bank_statement.py
index 8ddf1b6000a..7799968263d 100644
--- a/addons/account/models/account_bank_statement.py
+++ b/addons/account/models/account_bank_statement.py
@@ -332,6 +332,9 @@ class AccountBankStatement(models.Model):
                 statement.name = st_number
             statement.state = 'open'
 
+    def button_reopen(self):
+        self.state = 'open'
+
     def action_bank_reconcile_bank_statements(self):
         self.ensure_one()
         bank_stmt_lines = self.mapped('line_ids')
@@ -445,9 +448,9 @@ class AccountBankStatementLine(models.Model):
         if aml_to_cancel:
             aml_to_cancel.remove_move_reconcile()
             moves_to_cancel = aml_to_cancel.mapped('move_id')
-            moves_to_cancel.button_cancel()
             moves_to_cancel.button_draft()
-            moves_to_cancel.unlink()
+            moves_to_cancel.button_cancel()
+            moves_to_cancel.with_context(force_delete=True).unlink()
         if payment_to_cancel:
             payment_to_cancel.unlink()
 
diff --git a/addons/account/models/account_move.py b/addons/account/models/account_move.py
index 131ca0f3a53..2bfe746fbce 100644
--- a/addons/account/models/account_move.py
+++ b/addons/account/models/account_move.py
@@ -10,6 +10,8 @@ from datetime import date
 from itertools import groupby, chain
 from stdnum.iso7064 import mod_97_10
 from itertools import zip_longest
+from hashlib import sha256
+from json import dumps
 
 import json
 import re
@@ -18,6 +20,9 @@ import psycopg2
 
 _logger = logging.getLogger(__name__)
 
+#forbidden fields
+INTEGRITY_HASH_MOVE_FIELDS = ['date', 'journal_id', 'company_id']
+INTEGRITY_HASH_LINE_FIELDS = ['debit', 'credit', 'account_id', 'partner_id']
 
 class AccountMove(models.Model):
     _name = "account.move"
@@ -168,8 +173,7 @@ class AccountMove(models.Model):
         domain="[('company_id', '=', company_id)]",
         help="Fiscal positions are used to adapt taxes and accounts for particular customers or sales orders/invoices. "
              "The default value comes from the customer.")
-    invoice_user_id = fields.Many2one('res.users', readonly=True, copy=False, tracking=True,
-        states={'draft': [('readonly', False)]},
+    invoice_user_id = fields.Many2one('res.users', copy=False, tracking=True,
         string='Salesperson',
         default=lambda self: self.env.user)
     user_id = fields.Many2one(string='User', related='invoice_user_id',
@@ -184,8 +188,7 @@ class AccountMove(models.Model):
         states={'draft': [('readonly', False)]})
     invoice_date_due = fields.Date(string='Due Date', readonly=True, index=True, copy=False,
         states={'draft': [('readonly', False)]})
-    invoice_payment_ref = fields.Char(string='Payment Reference', index=True, copy=False, readonly=True,
-        states={'draft': [('readonly', False)]},
+    invoice_payment_ref = fields.Char(string='Payment Reference', index=True, copy=False,
         help="The payment reference to set on journal items.")
     invoice_sent = fields.Boolean(readonly=True, default=False, copy=False,
         help="It indicates that the invoice has been sent.")
@@ -201,7 +204,7 @@ class AccountMove(models.Model):
         states={'draft': [('readonly', False)]})
     invoice_partner_bank_id = fields.Many2one('res.partner.bank', string='Bank Account',
         help='Bank Account Number to which the invoice will be paid. A Company bank account if this is a Customer Invoice or Vendor Credit Note, otherwise a Partner bank account number.',
-        readonly=True, states={'draft': [('readonly', False)]}, domain="['|', ('company_id', '=', False), ('company_id', '=', company_id)]")
+        domain="['|', ('company_id', '=', False), ('company_id', '=', company_id)]")
     invoice_incoterm_id = fields.Many2one('account.incoterms', string='Incoterm',
         default=_get_default_invoice_incoterm,
         help='International Commercial Terms are a series of predefined commercial terms used in international transactions.')
@@ -244,6 +247,11 @@ class AccountMove(models.Model):
         help="Technical field used to display an alert on invoices if there is at least a matching amount in any supsense account.")
     # Technical field to hide Reconciled Entries stat button
     has_reconciled_entries = fields.Boolean(compute="_compute_has_reconciled_entries")
+    # ==== Hash Fields ====
+    restrict_mode_hash_table = fields.Boolean(related='journal_id.restrict_mode_hash_table')
+    secure_sequence_number = fields.Integer(string="Inalteralbility No Gap Sequence #", readonly=True, copy=False)
+    inalterable_hash = fields.Char(string="Inalterability Hash", readonly=True, copy=False)
+    string_to_hash = fields.Char(compute='_compute_string_to_hash', readonly=True)
 
     # -------------------------------------------------------------------------
     # ONCHANGE METHODS
@@ -1502,12 +1510,29 @@ class AccountMove(models.Model):
     def write(self, vals):
         not_paid_invoices = self.filtered(lambda move: move.is_invoice(include_receipts=True) and move.invoice_payment_state not in ('paid', 'in_payment'))
 
+        for move in self:
+            if (move.restrict_mode_hash_table and move.state == "posted" and set(vals).intersection(INTEGRITY_HASH_MOVE_FIELDS)):
+                raise UserError(_("You cannot edit the following fields due to restrict mode being activated on the journal: %s.") % ', '.join(INTEGRITY_HASH_MOVE_FIELDS))
+            if (move.restrict_mode_hash_table and move.inalterable_hash and 'inalterable_hash' in vals) or (move.secure_sequence_number and 'secure_sequence_number' in vals):
+                raise UserError(_('You cannot overwrite the values ensuring the inalterability of the accounting.'))
+            if (move.name != '/' and 'journal_id' in vals and move.journal_id.id != vals['journal_id']):
+                raise UserError(_('You cannot edit the journal of an account move if it has been posted once.'))
+            if 'date' in vals and move.date != vals['date']:
+                move._check_move_consistency(check_balanced=False)
+
         if self._move_autocomplete_invoice_lines_write(vals):
             res = True
         else:
             vals.pop('invoice_line_ids', None)
             res = super(AccountMove, self.with_context(check_move_validity=False)).write(vals)
 
+        if ('state' in vals and vals.get('state') == 'posted') and self.restrict_mode_hash_table:
+            for move in self.filtered(lambda m: not(m.secure_sequence_number or m.inalterable_hash)):
+                new_number = move.journal_id.secure_sequence_id.next_by_id()
+                vals_hashing = {'secure_sequence_number': new_number,
+                                'inalterable_hash': move._get_new_hash(new_number)}
+                res |= super(AccountMove, move).write(vals_hashing)
+
         # Ensure the move is still well balanced.
         if 'line_ids' in vals and self._context.get('check_move_validity', True):
             # 'check_move_validity' is needed as the write will be done line per line.
@@ -1520,8 +1545,8 @@ class AccountMove(models.Model):
 
     def unlink(self):
         for move in self:
-            # check the lock date + check if some entries are reconciled
-            move.line_ids._update_check()
+            if move.name != '/' and not self._context.get('force_delete'):
+                raise UserError(_("You cannot delete an entry which has been posted once."))
             move.line_ids.unlink()
         return super(AccountMove, self).unlink()
 
@@ -2000,11 +2025,6 @@ class AccountMove(models.Model):
         return lines.reconcile()
 
     def button_draft(self):
-        if any(move.state != 'cancel' for move in self):
-            raise UserError(_('Only cancelled journal entries can be reset to draft.'))
-        self.write({'state': 'draft'})
-
-    def button_cancel(self):
         self._check_tax_lock_date()
         AccountMoveLine = self.env['account.move.line']
         excluded_move_ids = []
@@ -2014,21 +2034,20 @@ class AccountMove(models.Model):
 
         for move in self:
             if move in move.line_ids.mapped('full_reconcile_id.exchange_move_id'):
-                raise UserError(_('You cannot cancel an exchange difference journal entry.'))
+                raise UserError(_('You cannot reset to draft an exchange difference journal entry.'))
             if move.tax_cash_basis_rec_id:
-                raise UserError(_('You cannot cancel a tax cash basis journal entry.'))
-            if not move.journal_id.update_posted and move.id not in excluded_move_ids:
-                raise UserError(_('You cannot modify a posted entry of this journal.\nFirst you should set the journal to allow cancelling entries.'))
+                raise UserError(_('You cannot reset to draft a tax cash basis journal entry.'))
+            if move.restrict_mode_hash_table and move.state == 'posted' and move.id not in excluded_move_ids:
+                raise UserError(_('You cannot modify a posted entry of this journal because it is in strict mode.'))
             # We remove all the analytics entries for this journal
             move.mapped('line_ids.analytic_line_ids').unlink()
-        if self.ids:
-            self.check_access_rights('write')
-            self.check_access_rule('write')
-            self._check_fiscalyear_lock_date()
-            self._cr.execute('UPDATE account_move SET state=%s WHERE id IN %s', ('cancel', tuple(self.ids)))
-            self.invalidate_cache()
+
         self._check_fiscalyear_lock_date()
         self.mapped('line_ids').remove_move_reconcile()
+        self.write({'state': 'draft'})
+
+    def button_cancel(self):
+        self.write({'state': 'cancel'})
         return True
 
     def action_invoice_sent(self):
@@ -2060,6 +2079,51 @@ class AccountMove(models.Model):
             'context': ctx,
         }
 
+    def _get_new_hash(self, secure_seq_number):
+        """ Returns the hash to write on journal entries when they get posted"""
+        self.ensure_one()
+        #get the only one exact previous move in the securisation sequence
+        prev_move = self.search([('state', '=', 'posted'),
+                                 ('company_id', '=', self.company_id.id),
+                                 ('journal_id', '=', self.journal_id.id),
+                                 ('secure_sequence_number', '!=', 0),
+                                 ('secure_sequence_number', '=', int(secure_seq_number) - 1)])
+        if prev_move and len(prev_move) != 1:
+            raise UserError(
+               _('An error occured when computing the inalterability. Impossible to get the unique previous posted journal entry.'))
+
+        #build and return the hash
+        return self._compute_hash(prev_move.inalterable_hash if prev_move else u'')
+
+    def _compute_hash(self, previous_hash):
+        """ Computes the hash of the browse_record given as self, based on the hash
+        of the previous record in the company's securisation sequence given as parameter"""
+        self.ensure_one()
+        hash_string = sha256((previous_hash + self.string_to_hash).encode('utf-8'))
+        return hash_string.hexdigest()
+
+    def _compute_string_to_hash(self):
+        def _getattrstring(obj, field_str):
+            field_value = obj[field_str]
+            if obj._fields[field_str].type == 'many2one':
+                field_value = field_value.id
+            return str(field_value)
+
+        for move in self:
+            values = {}
+            for field in INTEGRITY_HASH_MOVE_FIELDS:
+                values[field] = _getattrstring(move, field)
+
+            for line in move.line_ids:
+                for field in INTEGRITY_HASH_LINE_FIELDS:
+                    k = 'line_%d_%s' % (line.id, field)
+                    values[k] = _getattrstring(line, field)
+            #make the json serialization canonical
+            #  (https://tools.ietf.org/html/draft-staykov-hu-json-canonical-form-00)
+            move.string_to_hash = dumps(values, sort_keys=True,
+                                                ensure_ascii=True, indent=None,
+                                                separators=(',',':'))
+
     def action_invoice_print(self):
         """ Print the invoice and mark it as sent, so that we can see more
             easily the next step of the workflow
@@ -2282,11 +2346,11 @@ class AccountMoveLine(models.Model):
     amount_residual_currency = fields.Monetary(string='Residual Amount in Currency', store=True,
         compute='_amount_residual',
         help="The residual amount on a journal item expressed in its currency (possibly not the company currency).")
-    full_reconcile_id = fields.Many2one('account.full.reconcile', string="Matching #", copy=False, index=True)
+    full_reconcile_id = fields.Many2one('account.full.reconcile', string="Matching #", copy=False, index=True, readonly=True)
     matched_debit_ids = fields.One2many('account.partial.reconcile', 'credit_move_id', string='Matched Debits',
-        help='Debit journal items that are matched with this journal item.')
+        help='Debit journal items that are matched with this journal item.', readonly=True)
     matched_credit_ids = fields.One2many('account.partial.reconcile', 'debit_move_id', string='Matched Credits',
-        help='Credit journal items that are matched with this journal item.')
+        help='Credit journal items that are matched with this journal item.', readonly=True)
 
     # ==== Analytic fields ====
     analytic_line_ids = fields.One2many('account.analytic.line', 'move_id', string='Analytic lines')
@@ -2847,8 +2911,6 @@ class AccountMoveLine(models.Model):
         move_ids = set()
         for line in self:
             err_msg = _('Move name (id): %s (%s)') % (line.move_id.name, str(line.move_id.id))
-            if line.move_id.state == 'posted':
-                raise UserError(_('You cannot do this modification on a posted journal entry, you can just change some non legal fields. You must revert the journal entry to cancel it.\n%s.') % err_msg)
             if line.reconciled and not (line.debit == 0 and line.credit == 0):
                 raise UserError(_('You cannot do this modification on a reconciled entry. You can just change some non legal fields or you must unreconcile first.\n%s.') % err_msg)
             if line.move_id.id not in move_ids:
@@ -2970,8 +3032,13 @@ class AccountMoveLine(models.Model):
             # this is needed to compute the correct amount_residual_currency and potentially create an exchange difference entry
             self._update_check()
         # when making a reconciliation on an existing liquidity journal item, mark the payment as reconciled
-        for record in self:
-            if 'statement_line_id' in vals and record.payment_id:
+        for line in self:
+            if line.parent_state == 'posted':
+                if line.move_id.restrict_mode_hash_table and set(vals).intersection(INTEGRITY_HASH_LINE_FIELDS):
+                    raise UserError(_("You cannot edit the following fields due to restrict mode being activated on the journal: %s.") % ', '.join(INTEGRITY_HASH_LINE_FIELDS))
+                if any(key in vals for key in ('tax_ids', 'tax_line_ids')):
+                    raise UserError(_('You cannot modify the taxes related to a posted journal item, you should reset the journal entry to draft to do so.'))
+            if 'statement_line_id' in vals and line.payment_id:
                 # In case of an internal transfer, there are 2 liquidity move lines to match with a bank statement
                 if all(line.statement_id for line in record.payment_id.move_line_ids.filtered(
                         lambda r: r.id != record.id and r.account_id.internal_type == 'liquidity')):
diff --git a/addons/account/models/account_payment.py b/addons/account/models/account_payment.py
index 6b4dd3a1078..f15e1539ed1 100644
--- a/addons/account/models/account_payment.py
+++ b/addons/account/models/account_payment.py
@@ -441,16 +441,7 @@ class account_payment(models.Model):
                 payment.write({'state': 'posted'})
 
     def cancel(self):
-        for rec in self:
-            for move in rec.move_line_ids.mapped('move_id'):
-                if rec.reconciled_invoice_ids:
-                    move.line_ids.remove_move_reconcile()
-                if move.state != 'draft':
-                    move.button_cancel()
-                move.unlink()
-            rec.write({
-                'state': 'cancelled',
-            })
+        self.write({'state': 'cancelled'})
 
     def unlink(self):
         if any(bool(rec.move_line_ids) for rec in self):
@@ -703,7 +694,10 @@ class account_payment(models.Model):
         return True
 
     def action_draft(self):
-        return self.write({'state': 'draft'})
+        moves = self.mapped('move_line_ids.move_id')
+        moves.filtered(lambda move: move.state == 'posted').button_draft()
+        moves.with_context(force_delete=True).unlink()
+        self.write({'state': 'draft'})
 
     def _get_invoice_payment_amount(self, inv):
         """
diff --git a/addons/account/models/company.py b/addons/account/models/company.py
index e40265d4f64..7116dafff8c 100644
--- a/addons/account/models/company.py
+++ b/addons/account/models/company.py
@@ -6,7 +6,7 @@ from dateutil.relativedelta import relativedelta
 
 from odoo import fields, models, api, _
 from odoo.exceptions import ValidationError, UserError, RedirectWarning
-from odoo.tools.misc import DEFAULT_SERVER_DATE_FORMAT
+from odoo.tools.misc import DEFAULT_SERVER_DATE_FORMAT, format_date
 from odoo.tools.float_utils import float_round, float_is_zero
 from odoo.tools import date_utils
 from odoo.tests.common import Form
@@ -553,3 +553,82 @@ class ResCompany(models.Model):
                 "Please go to Account Configuration and select or install a fiscal localization.")
             raise RedirectWarning(msg, action.id, _("Go to the configuration panel"))
         return account
+
+    @api.model
+    def _action_check_hash_integrity(self):
+        return self.env.ref('account.action_report_account_hash_integrity').report_action(self.id)
+
+    def _check_hash_integrity(self):
+        """Checks that all posted moves have still the same data as when they were posted
+        and raises an error with the result.
+        """
+        def build_move_info(move):
+            return(move.name, move.inalterable_hash, fields.Date.to_string(move.date))
+
+        journals = self.env['account.journal'].search([('company_id', '=', self.id)])
+        results_by_journal = {
+            'results': [],
+            'printing_date': format_date(self.env, fields.Date.to_string(fields.Date.today()))
+        }
+
+        for journal in journals:
+            rslt = {
+                'journal_name': journal.name,
+                'journal_code': journal.code,
+                'restricted_by_hash_table': journal.restrict_mode_hash_table and 'V' or 'X',
+                'msg_cover': '',
+                'first_hash': 'None',
+                'first_move_name': 'None',
+                'first_move_date': 'None',
+                'last_hash': 'None',
+                'last_move_name': 'None',
+                'last_move_date': 'None',
+            }
+            if not journal.restrict_mode_hash_table:
+                rslt.update({'msg_cover': _('This journal is not in strict mode.')})
+                results_by_journal['results'].append(rslt)
+                continue
+
+            all_moves_count = self.env['account.move'].search_count([('state', '=', 'posted'), ('journal_id', '=', journal.id)])
+            moves = self.env['account.move'].search([('state', '=', 'posted'), ('journal_id', '=', journal.id),
+                                            ('secure_sequence_number', '!=', 0)], order="secure_sequence_number ASC")
+            if not moves:
+                rslt.update({
+                    'msg_cover': _('There isn\'t any journal entry flagged for data inalterability yet for this journal.'),
+                })
+                results_by_journal['results'].append(rslt)
+                continue
+
+            previous_hash = u''
+            start_move_info = []
+            hash_corrupted = False
+            for move in moves:
+                if move.inalterable_hash != move._compute_hash(previous_hash=previous_hash):
+                    rslt.update({'msg_cover': _('Corrupted data on journal entry with id %s.') % move.id})
+                    results_by_journal['results'].append(rslt)
+                    hash_corrupted = True
+                    break
+                if not previous_hash:
+                    #save the date and sequence number of the first move hashed
+                    start_move_info = build_move_info(move)
+                previous_hash = move.inalterable_hash
+            end_move_info = build_move_info(move)
+
+            if hash_corrupted:
+                continue
+
+            rslt.update({
+                        'first_move_name': start_move_info[0],
+                        'first_hash': start_move_info[1],
+                        'first_move_date': format_date(self.env, start_move_info[2]),
+                        'last_move_name': end_move_info[0],
+                        'last_hash': end_move_info[1],
+                        'last_move_date': format_date(self.env, end_move_info[2]),
+                    })
+            if len(moves) == all_moves_count:
+                rslt.update({'msg_cover': _('All entries are hashed.')})
+            else:
+                rslt.update({'msg_cover': _('Entries are hashed from %s (%s)') % (start_move_info[0], format_date(self.env, start_move_info[2]))})
+            results_by_journal['results'].append(rslt)
+
+        return results_by_journal
diff --git a/addons/account/report/__init__.py b/addons/account/report/__init__.py
index 0082db0381a..085f3cea256 100644
--- a/addons/account/report/__init__.py
+++ b/addons/account/report/__init__.py
@@ -4,3 +4,4 @@
 from . import account_invoice_report
 from . import account_journal
 from . import account_aged_partner_balance
+from . import account_hash_integrity_templates
diff --git a/addons/account/report/account_hash_integrity_templates.py b/addons/account/report/account_hash_integrity_templates.py
new file mode 100644
index 00000000000..fe246841522
--- /dev/null
+++ b/addons/account/report/account_hash_integrity_templates.py
@@ -0,0 +1,22 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo import api, fields, models
+
+
+class ReportAccountHashIntegrity(models.AbstractModel):
+    _name = 'report.account.report_hash_integrity'
+    _description = 'Get hash integrity result as PDF.'
+
+    @api.model
+    def _get_report_values(self, docids, data=None):
+        if data:
+            data.update(self.env.company._check_hash_integrity())
+        else:
+            data = self.env.company._check_hash_integrity()
+        return {
+            'doc_ids' : docids,
+            'doc_model' : self.env['res.company'],
+            'data' : data,
+            'docs' : self.env['res.company'].browse(self.env.company.id),
+        }
diff --git a/addons/account/report/account_hash_integrity_templates.xml b/addons/account/report/account_hash_integrity_templates.xml
new file mode 100644
index 00000000000..14716749395
--- /dev/null
+++ b/addons/account/report/account_hash_integrity_templates.xml
@@ -0,0 +1,106 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<odoo>
+    <data>
+        <template id="report_hash_integrity">
+            <t t-call="web.html_container">
+                <t t-foreach="docs" t-as="company">
+                    <t t-call="web.external_layout">
+                        <div class="page">
+                            <div class="row" id="hash_header">
+                                <div class="col-12">
+                                    <br/>
+                                    <h2>Hash Integrity Result - <span t-esc="data['printing_date']"/></h2>
+                                    <br/>
+                                </div>
+                            </div>
+                            <div class="row">
+                                <div class="col-12" id="hash_config_review">
+                                    <br/>
+                                    <h3>Configuration review</h3>
+                                    <br/>
+                                </div>
+                            </div>
+                            <div class="row">
+                                <div class="col-12">
+                                    <table class="table table-bordered" style="table-layout: fixed" id="hash_config_table">
+                                        <thead style="display: table-row-group">
+                                            <tr>
+                                                <th class="text-center" style="width: 30%" scope="col">Journal</th>
+                                                <th class="text-center" style="width: 20%" scope="col">Inalterability check</th>
+                                                <th class="text-center" style="width: 50%" scope="col">Coverage</th>
+                                            </tr>
+                                        </thead>
+                                        <tbody>
+                                            <t t-foreach="data['results']" t-as="result">
+                                                <tr>
+                                                    <td>
+                                                        [<span t-esc="result['journal_code']"/>] <span t-esc="result['journal_name']"/>
+                                                    </td>
+                                                    <td class="text-center"><span t-esc="result['restricted_by_hash_table']"/></td>
+                                                    <td><span t-esc="result['msg_cover']"/></td>
+                                                </tr>
+                                            </t>
+                                        </tbody>
+                                    </table>
+                                </div>
+                            </div>
+                            <t t-if="any(result['first_hash'] != 'None' for result in data['results'])">
+                                <div class="row" style="page-break-before:always;">
+                                    <div class="col-12" id="hash_data_consistency">
+                                        <br/>
+                                        <h3>Data consistency check</h3>
+                                        <br/>
+                                    </div>
+                                </div>
+                                <div class="row">
+                                    <div class="col-12" id="hash_data_consistency_table">
+                                        <table class="table table-bordered" style="table-layout: fixed">
+                                            <thead style="display: table-row-group">
+                                                <tr>
+                                                    <th class="text-center" style="width: 20%" scope="col">Journal</th>
+                                                    <th class="text-center" style="width: 20%" scope="col">First Hash</th>
+                                                    <th class="text-center" style="width: 20%" scope="col">First Entry</th>
+                                                    <th class="text-center" style="width: 20%" scope="col">Last Hash</th>
+                                                    <th class="text-center" style="width: 20%" scope="col">Last Entry</th>
+                                                </tr>
+                                            </thead>
+                                            <tbody>
+                                                <t t-foreach="data['results']" t-as="result">
+                                                    <t t-if="result['first_hash'] != 'None'">
+                                                        <tr>
+                                                            <td><span t-esc="result['journal_code']"/></td>
+                                                            <td><span t-esc="result['first_hash']"/></td>
+                                                            <td>
+                                                                <span t-esc="result['first_move_name']"/> <br/>
+                                                                <span t-esc="result['first_move_date']"/>
+                                                            </td>
+                                                            <td><span t-esc="result['last_hash']"/></td>
+                                                            <td>
+                                                                <span t-esc="result['last_move_name']"/> <br/>
+                                                                <span t-esc="result['last_move_date']"/>
+                                                            </td>
+                                                        </tr>
+                                                    </t>
+                                                </t>
+                                            </tbody>
+                                        </table>
+                                    </div>
+                                </div>
+                                <div class="row" id="hash_last_div">
+                                    <div class="col-12" id="hash_chain_compliant">
+                                        <br/>
+                                        <h6>
+                                            The hash chain is compliant: it is not possible to alter the
+                                            data without breaking the hash chain for subsequent parts.
+                                        </h6>
+                                        <br/>
+                                    </div>
+                                </div>
+                            </t>
+                        </div>
+                    </t>
+                </t>
+            </t>
+        </template>
+    </data>
+</odoo>
diff --git a/addons/account/tests/test_account_move_partner_count.py b/addons/account/tests/test_account_move_partner_count.py
index 68527cf7572..203c4dc0493 100644
--- a/addons/account/tests/test_account_move_partner_count.py
+++ b/addons/account/tests/test_account_move_partner_count.py
@@ -45,6 +45,7 @@ class TestAccountMovePartnerCount(TransactionCase):
         with self.registry.cursor() as cr:
             env = self.env(cr=cr)
             move = self.move.with_env(env)
+            move.name = '/'
             move.state = 'draft'
             move.unlink()
             self.journal.with_env(env).unlink()
diff --git a/addons/account/tests/test_account_move_tax_lock_date.py b/addons/account/tests/test_account_move_tax_lock_date.py
index 280536e6b46..efd383cb815 100644
--- a/addons/account/tests/test_account_move_tax_lock_date.py
+++ b/addons/account/tests/test_account_move_tax_lock_date.py
@@ -19,12 +19,11 @@ class TestTaxBlockDate(AccountingTestCase):
         self.company = self.env.company
         company_id = self.company.id
 
-        last_day_month = date.today()
-        self.last_day_month = last_day_month.replace(day=monthrange(last_day_month.year, last_day_month.month)[1])
-        first_day_month = date.today()
-        self.first_day_month = first_day_month.replace(day=1)
-        middle_day_month = date.today()
-        middle_day_month = middle_day_month.replace(day=15)
+        last_day_previous_month = date.today()
+        last_day_previous_month = last_day_previous_month.replace(month=last_day_previous_month.month-1)
+        self.last_day_previous_month = last_day_previous_month.replace(day=monthrange(last_day_previous_month.year, last_day_previous_month.month)[1])
+        self.first_day_previous_month = self.last_day_previous_month.replace(day=1)
+        middle_day_previous_month = self.last_day_previous_month.replace(day=15)
 
         self.sale_journal_id = self.env['account.journal'].search([('type', '=', 'sale'), ('company_id', '=', company_id)], limit=1)[0]
         self.account_id = self.env['account.account'].search([('internal_type', '=', 'receivable'), ('company_id', '=', company_id)], limit=1)[0]
@@ -34,7 +33,7 @@ class TestTaxBlockDate(AccountingTestCase):
         self.move = {
             'name': '/',
             'journal_id': self.sale_journal_id.id,
-            'date': middle_day_month,
+            'date': middle_day_previous_month,
             'line_ids': [(0, 0, {
                     'name': 'foo',
                     'debit': 10,
@@ -50,7 +49,7 @@ class TestTaxBlockDate(AccountingTestCase):
         self.move_no_tax = {
             'name': '/',
             'journal_id': self.sale_journal_id.id,
-            'date': middle_day_month,
+            'date': middle_day_previous_month,
             'line_ids': [(0, 0, {
                     'name': 'foo',
                     'debit': 10,
@@ -67,32 +66,31 @@ class TestTaxBlockDate(AccountingTestCase):
         before the tax lock date.
         """
         # Posting after the lock date is always allowed
-        self.company.tax_lock_date = self.first_day_month
+        self.company.tax_lock_date = self.first_day_previous_month
         # copy() because mail.thread modifies the dictionary given to create
         move_after_lock = self.env['account.move'].create(self.move.copy())
         move_after_lock.post()
 
         # Posting before the tax lock date is allowed only if the move doesn't contain any tax
-        self.user_id.company_id.tax_lock_date = self.last_day_month
+        self.user_id.company_id.tax_lock_date = self.last_day_previous_month
         move_before_lock_no_tax = self.env['account.move'].create(self.move_no_tax)
         move_before_lock_no_tax.post()
 
         # Posting before the tax lock date is not allowed for moves impacting the tax report
-        self.user_id.company_id.tax_lock_date = self.last_day_month
+        self.user_id.company_id.tax_lock_date = self.last_day_previous_month
         with self.assertRaises(UserError):
             self.env['account.move'].create(self.move.copy())
 
-    def test_tax_lock_date_cancel(self):
-        """ Checks that it is not possible to cancel an entry posted before the
+    def test_tax_lock_date_reset_to_draft(self):
+        """ Checks that it is not possible to reset to draft an entry posted before the
         tax lock date if it impacts the tax report. """
-        self.sale_journal_id.update_posted = True
         move = self.env['account.move'].create(self.move)
         move.post()
         move_no_tax = self.env['account.move'].create(self.move_no_tax)
         move_no_tax.post()
 
-        self.user_id.company_id.tax_lock_date = self.last_day_month
+        self.user_id.company_id.tax_lock_date = self.last_day_previous_month
 
-        move_no_tax.button_cancel()
+        move_no_tax.button_draft()
         with self.assertRaises(UserError):
-            move.button_cancel()
+            move.button_draft()
diff --git a/addons/account/tests/test_payment.py b/addons/account/tests/test_payment.py
index 557a482d34f..953d6c1754c 100644
--- a/addons/account/tests/test_payment.py
+++ b/addons/account/tests/test_payment.py
@@ -428,9 +428,7 @@ class TestPayment(AccountingTestCase):
         # The invoice should now be paid
         self.assertEqual(invoice.invoice_payment_state, 'paid', "Invoice should be in 'paid' state after having reconciled the two payments with a bank statement")
 
-    def test_payment_cancel_keep_name(self):
-        self.bank_journal_euro.update_posted = True
-
+    def test_payment_draft_keep_name(self):
         payment = self.payment_model.create({
             'payment_type': 'inbound',
             'payment_method_id': self.payment_method_manual_in.id,
@@ -447,18 +445,14 @@ class TestPayment(AccountingTestCase):
         name = payment.move_line_ids.mapped('move_id').name
         self.assertTrue(name)
 
-        payment.cancel()
-        self.assertFalse(payment.move_line_ids.mapped('move_id'))
         payment.action_draft()
+        self.assertFalse(payment.move_line_ids.mapped('move_id'))
 
         payment.post()
         self.assertEqual(len(payment.move_line_ids.mapped('move_id')), 1)
         self.assertEqual(name, payment.move_line_ids.mapped('move_id').name)
 
-    def test_payment_transfer_cancel_keep_names(self):
-        self.bank_journal_euro.update_posted = True
-        self.cash_journal_euro.update_posted = True
-
+    def test_payment_transfer_draft_keep_names(self):
         payment = self.payment_model.create({
             'payment_type': 'transfer',
             'payment_method_id': self.payment_method_manual_out.id,
@@ -487,9 +481,8 @@ class TestPayment(AccountingTestCase):
         self.assertEqual(reconciled_lines.mapped('move_id'), all_moves)
 
         reconciled_lines.remove_move_reconcile()
-        payment.cancel()
-        self.assertFalse(payment.move_line_ids.mapped('move_id'))
         payment.action_draft()
+        self.assertFalse(payment.move_line_ids.mapped('move_id'))
 
         payment.post()
         self.assertEqual(len(payment.move_line_ids.mapped('move_id')), 2)
@@ -502,9 +495,7 @@ class TestPayment(AccountingTestCase):
         self.assertEqual(name, move.name)
         self.assertEqual(transfer_name, transfer_move.name)
 
-    def test_payment_cancel_to_transfer(self):
-        self.bank_journal_euro.update_posted = True
-
+    def test_payment_draft_to_transfer(self):
         payment = self.payment_model.create({
             'payment_type': 'inbound',
             'payment_method_id': self.payment_method_manual_in.id,
@@ -521,9 +512,8 @@ class TestPayment(AccountingTestCase):
         name = payment.move_line_ids.mapped('move_id').name
         self.assertTrue(name)
 
-        payment.cancel()
-        self.assertFalse(payment.move_line_ids.mapped('move_id'))
         payment.action_draft()
+        self.assertFalse(payment.move_line_ids.mapped('move_id'))
 
         payment.write({
             'payment_type': 'transfer',
diff --git a/addons/account/tests/test_reconciliation.py b/addons/account/tests/test_reconciliation.py
index 94e5e69bee4..91c52a22c85 100644
--- a/addons/account/tests/test_reconciliation.py
+++ b/addons/account/tests/test_reconciliation.py
@@ -1506,7 +1506,7 @@ class TestReconciliationExec(TestReconciliation):
         partner = self.env['res.partner'].create({'name': 'UncertainPartner'})
         currency = self.env.company.currency_id
         invoice = self.create_invoice_partner(currency_id=currency.id, partner_id=partner.id)
-        journal = self.env['account.journal'].create({'name': 'Bank', 'type': 'bank', 'code': 'THE', 'update_posted':True})
+        journal = self.env['account.journal'].create({'name': 'Bank', 'type': 'bank', 'code': 'THE', 'restrict_mode_hash_table':False})
 
         statement = self.make_payment(invoice, journal, 50)
         st_line = statement.line_ids
diff --git a/addons/account/views/account_move_views.xml b/addons/account/views/account_move_views.xml
index 12aace1ff9b..2def26b8cb3 100644
--- a/addons/account/views/account_move_views.xml
+++ b/addons/account/views/account_move_views.xml
@@ -27,7 +27,7 @@
                                         <field name="account_id" options="{'no_create': True}" domain="[('company_id', '=', company_id)]" attrs="{'readonly':[('parent_state','=','posted')]}"/>
                                         <field name="debit" attrs="{'readonly':[('parent_state','=','posted')]}"/>
                                         <field name="credit" attrs="{'readonly':[('parent_state','=','posted')]}"/>
-                                        <field name="quantity"/>
+                                        <field name="quantity" attrs="{'readonly':[('parent_state','=','posted')]}"/>
                                     </group>
                                     <group string="Accounting Documents">
                                         <field name="move_id" attrs="{'readonly':[('parent_state','=','posted')]}"/>
@@ -68,8 +68,10 @@
                                         <field name="blocked"/>
                                     </group>
                                     <group string="Analytic" groups="analytic.group_analytic_accounting,analytic.group_analytic_tags">
-                                        <field name="analytic_account_id" groups="analytic.group_analytic_accounting"/>
-                                        <field name="analytic_tag_ids" groups="analytic.group_analytic_tags" widget="many2many_tags"/>
+                                        <field name="analytic_account_id" groups="analytic.group_analytic_accounting"
+                                            attrs="{'readonly':[('parent_state','=','posted')]}"/>
+                                        <field name="analytic_tag_ids" groups="analytic.group_analytic_tags"
+                                            widget="many2many_tags"/>
                                     </group>
                                 </group>
                             </page>
@@ -138,7 +140,7 @@
                     <field name="company_id" groups="base.group_multi_company" options="{'no_create': True}"/>
                     <field name="journal_id" options='{"no_open":True}'/>
                     <field name="move_id" optional="show"/>
-                    <field name="account_id" options="{'no_open': True, 'no_create': True}" domain="[('company_id', '=', company_id)]" groups="account.group_account_user" attrs="{'readonly':[('parent_state','=','posted')]}"/>
+                    <field name="account_id" options="{'no_open': True, 'no_create': True}" domain="[('company_id', '=', company_id)]" groups="account.group_account_user"/>
                     <field name="partner_id" optional="show"/>
                     <field name="statement_id" invisible="1"/>
                     <field name="ref" optional="show"/>
@@ -507,6 +509,10 @@
                         <button name="action_duplicate" string="Duplicate" type="object" groups="account.group_account_invoice"
                                 attrs="{'invisible': [('type', '!=', 'entry')]}"/>
                         <!-- Cancel -->
+                        <button name="button_cancel" string="Cancel Entry" type="object" groups="account.group_account_invoice"
+                                attrs="{'invisible' : ['|', ('id', '=', False), ('state', '!=', 'draft')]}"/>
+                        <button name="button_draft" string="Reset to Draft" type="object" groups="account.group_account_invoice"
+                                attrs="{'invisible' : ['|', ('restrict_mode_hash_table', '=', True), ('state', 'not in', ('posted', 'cancel'))]}"/>
                         <field name="state" widget="statusbar" statusbar_visible="draft,posted"/>
                     </header>
                     <!-- Invoice outstanding credits -->
@@ -557,6 +563,7 @@
                         <field name="invoice_sequence_number_next" invisible="1"/>
                         <field name="invoice_has_matching_suspense_amount" invisible="1"/>
                         <field name="has_reconciled_entries" invisible="1"/>
+                        <field name="restrict_mode_hash_table" invisible="1"/>
 
                         <div>
                             <!-- Invoice draft header -->
@@ -642,7 +649,8 @@
                                        invisible="context.get('default_journal_id') and context.get('type', 'entry') != 'entry'"
                                        groups="account.group_account_user"
                                        options="{'no_create': True}"
-                                       domain="[('type', '=?', invoice_filter_type_domain)]"/>
+                                       domain="[('type', '=?', invoice_filter_type_domain)]"
+                                       attrs="{'readonly': [('name', '!=', '/')]}"/>
 
                                 <field name="company_id" groups="base.group_multi_company"/>
 
@@ -866,6 +874,7 @@
                                            attrs="{'invisible': [('type', 'not in', ('out_invoice', 'out_refund', 'in_invoice', 'in_refund'))]}">
                                         <field name="invoice_incoterm_id"/>
                                         <field name="fiscal_position_id"/>
+                                        <field name="inalterable_hash" groups="base.group_no_one,account.group_account_user"/>
                                         <field name="invoice_cash_rounding_id" groups="account.group_cash_rounding"/>
                                         <field name="invoice_source_email"
                                                widget="email"
@@ -874,9 +883,10 @@
                                     <group string="Payments"
                                            name="payments_info_group"
                                            attrs="{'invisible': [('type', 'not in', ('out_invoice', 'out_refund', 'in_invoice', 'in_refund'))]}">
-                                        <field name="invoice_payment_ref"/>
+                                        <field name="invoice_payment_ref" attrs="{'readonly': [('state', '=', 'paid'), ('type', 'in', ('in_invoice', 'in_refund'))]}"/>
                                         <field name="invoice_partner_bank_id"
-                                               domain="[('partner_id', '=', bank_partner_id)]"/>
+                                               domain="[('partner_id', '=', bank_partner_id)]"
+                                               attrs="{'readonly': [('state', '=', 'paid')]}"/>
                                     </group>
                                 </group>
                             </page>
@@ -893,6 +903,7 @@
                                     </group>
                                     <group>
                                         <field name="company_id" groups="base.group_multi_company" required="1"/>
+                                        <field name="inalterable_hash" groups="base.group_no_one,account.group_account_user"/>
                                     </group>
                                 </group>
                             </page>
@@ -1279,6 +1290,16 @@ if records:
             </field>
         </record>
 
+        <record model="ir.actions.server" id="action_check_hash_integrity">
+            <field name="name">Data Inalterability Check</field>
+            <field name="model_id" ref="account.model_res_company"/>
+            <field name="type">ir.actions.server</field>
+            <field name="state">code</field>
+            <field name="code">
+                action = env.company._action_check_hash_integrity()
+            </field>
+        </record>
+
         <!-- MENUS -->
 
         <menuitem
diff --git a/addons/account/views/account_payment_view.xml b/addons/account/views/account_payment_view.xml
index 3f879df6da3..7242a091a2f 100644
--- a/addons/account/views/account_payment_view.xml
+++ b/addons/account/views/account_payment_view.xml
@@ -126,8 +126,9 @@
                 <form string="Register Payment">
                     <header>
                         <button name="post" class="oe_highlight" states="draft" string="Confirm" type="object"/>
-                        <button name="action_draft" class="oe_highlight" states="cancelled" string="Set To Draft" type="object"/>
-                        <field name="state" widget="statusbar" statusbar_visible="draft,posted,reconciled"/>
+                        <button name="action_draft" class="btn btn-secondary" states="posted" string="Reset To Draft" type="object"/>
+                        <button name="cancel" attrs="{'invisible': [('state', 'in', ('cancelled', 'posted'))]}" string="Cancel" type="object"/>
+                        <field name="state" widget="statusbar" statusbar_visible="draft,posted,reconciled,cancelled"/>
                     </header>
                     <sheet>
                         <div class="oe_button_box" name="button_box">
diff --git a/addons/account/views/account_report.xml b/addons/account/views/account_report.xml
index 86f2281424d..11d6e792f47 100644
--- a/addons/account/views/account_report.xml
+++ b/addons/account/views/account_report.xml
@@ -75,5 +75,15 @@
             report_type="qweb-pdf"
         />
 
+        <report
+            id="action_report_account_hash_integrity"
+            model="res.company"
+            string="Hash integrity result PDF"
+            report_type="qweb-pdf"
+            name="account.report_hash_integrity"
+            file="account.report_hash_integrity"
+            menu="False"
+        />
+
     </data>
 </odoo>
diff --git a/addons/account/views/account_view.xml b/addons/account/views/account_view.xml
index 39865207430..86e8dfff114 100644
--- a/addons/account/views/account_view.xml
+++ b/addons/account/views/account_view.xml
@@ -319,6 +319,7 @@
                                         <div class="text-muted" colspan="2">Keep empty for no control</div>
                                         <field name="type_control_ids" widget="many2many_tags"/>
                                         <field name="account_control_ids" widget="many2many_tags"/>
+                                        <field name="restrict_mode_hash_table" groups="account.group_account_user"/>
                                     </group>
                                     <group string="Payment Method Types" attrs="{'invisible': [('type', 'not in', ['bank', 'cash'])]}">
                                         <field name="inbound_payment_method_ids" widget="many2many_checkboxes"/>
@@ -640,6 +641,7 @@ action = model.setting_init_bank_account_action()
                     <field name="all_lines_reconciled" invisible="1" />
                     <button name="action_bank_reconcile_bank_statements" string="Reconcile" type="object" class="oe_highlight" attrs="{'invisible':['|','|',('all_lines_reconciled','=',True),('line_ids','=',[]),('state', '!=', 'open')]}"/>
                     <button name="check_confirm_bank" string="Validate" type="object" class="oe_highlight" attrs="{'invisible':['|','|',('all_lines_reconciled','=',False),('line_ids','=',[]),('state', '!=', 'open')]}"/>
+                    <button name="button_reopen" states="confirm" string="Reset to New" type="object"/>
                     <button name="%(action_cash_box_out)d" string="Take Money In/Out" type="action" class="oe_highlight" attrs="{'invisible': [('journal_type','!=','cash')]}"/>
                     <field name="state" widget="statusbar" statusbar_visible="open,confirm"/>
                 </header>
@@ -698,6 +700,8 @@ action = model.setting_init_bank_account_action()
                                     <field name="account_number" optional="hidden"/>
                                     <field name="amount_currency" optional="hidden"/>
                                     <field name="currency_id" optional="hidden"/>
+                                    <field name="state" invisible="1"/>
+                                    <button name="button_cancel_reconciliation" attrs="{'invisible': ['|',('journal_entry_ids', '=', []), ('state', '=', 'confirm')]}" string="Revert reconciliation" type="object" icon="fa-undo"/>
                                 </tree>
                             </field>
                         </page>