b3ed49c167
We did a big refactor of the hash in https://github.com/odoo/odoo/pull/160820@ This commit updates the documentation accordingly. task-id 3820975 closes odoo/documentation#8581 Signed-off-by: Jonathan Castillo (jcs) <jcs@odoo.com>
72 lines
3.6 KiB
ReStructuredText
72 lines
3.6 KiB
ReStructuredText
================================
|
|
Data inalterability check report
|
|
================================
|
|
|
|
Tax authorities in some countries require companies to **prove their posted accounting entries are
|
|
inalterable**, meaning that once an entry has been posted, it can no longer be changed.
|
|
|
|
To do so, Odoo can use the **SHA-256 algorithm** to create a unique fingerprint for each posted
|
|
entry. This fingerprint is called a hash. The hash is generated by taking an entry's essential data
|
|
(the values of the `name`, `date`, `journal_id`, `company_id`, `debit`, `credit`, `account_id`, and
|
|
`partner_id` fields), concatenating it, and inputting it to the SHA-256 hash function, which then
|
|
outputs a fixed size (256-bit) string of characters. The hash function is deterministic (:dfn:`the
|
|
same input always creates the same output`): any minor modification to the original data would
|
|
completely change the resulting hash. Consequently, the SHA-256 algorithm is often used, among
|
|
others, for data integrity verification purposes.
|
|
|
|
In addition, the previous entry's hash is always added to the next entry to form a **hash chain**.
|
|
This is used to ensure a new entry is not added afterward between two posted entries, as doing so
|
|
would break the hash chain.
|
|
|
|
.. note::
|
|
Hashes generated by the SHA-256 algorithm are theoretically not unique, as there is a finite
|
|
number of possible values. However, this number is exceptionally high: 2²⁵⁶, which is a lot
|
|
bigger than the number of atoms in the known universe. This is why hashes are considered unique
|
|
in practice.
|
|
|
|
.. _data-inalterability/lock:
|
|
|
|
Lock entries with hash
|
|
======================
|
|
|
|
To start using the hashing function, go to :menuselection:`Accounting --> Configuration > Journals`.
|
|
Open the journal for which you want to activate the feature, go to the :guilabel:`Advanced Settings`
|
|
tab, and enable :guilabel:`Lock Sent Invoices with Hash` for sale journals, or
|
|
:guilabel:`Lock Entries Manually` for purchase and general journals.
|
|
|
|
For sale journals, the entry is automatically locked once it is sent. You can also click on the
|
|
button :guilabel:`Lock` on the invoice to lock it without sending it. For sale, purchase, and
|
|
general journals, the locking is always done manually using the same button.
|
|
|
|
To compute the hash of an entry, Odoo retrieves the predecessor entries of the chain (i.e., the
|
|
entries with the same sequence prefix) and hashes them in a continuous way from the last hashed
|
|
entry to the new entry to hash.
|
|
|
|
.. warning::
|
|
Once you lock an entry in a locked journal, you cannot disable the feature anymore, nor edit any
|
|
locked entry.
|
|
|
|
.. _data-inalterability/report:
|
|
|
|
Report download
|
|
===============
|
|
|
|
To download the data inalterability check report, go to :menuselection:`Accounting --> Configuration
|
|
--> Settings --> Reporting` and click on :guilabel:`Download the Data Inalterability Check Report`.
|
|
|
|
The report's first section is an overview of all your journals and their configuration. Under the
|
|
inalterability check column, you can see whether or not a journal's entries are locked with a hash
|
|
(V) or not (X). The coverage column tells you when a journal's entries started being locked.
|
|
|
|
.. image:: data_inalterability/journal-overview.png
|
|
:align: center
|
|
:alt: Configuration report for two journals
|
|
|
|
The second section gives you the result of the data consistency check for each hashed journal. You
|
|
can view the first hashed entry and its corresponding hash and the last hashed entry and its
|
|
corresponding hash.
|
|
|
|
.. image:: data_inalterability/data-consistency-check.png
|
|
:align: center
|
|
:alt: Data consistency check report for a journal
|