The digital safe, explained simply
A digital safe is not merely a simple storage space: it is a preservation device that guarantees the integrity, date and origin of your documents over time. This guide explains how it works, its probative value, the regulatory framework (NF Z42-020, eIDAS) and the cases where it becomes essential.
What is a digital safe?
A digital safe is a secure preservation service that maintains your electronic documents in a reliable and durable manner. Unlike a hard drive or standard cloud storage, it ensures that each document remains unalterable, time-stamped and retrievable throughout its entire retention period.
In France, it complies with a specific regulatory framework: the NF Z42-020 standard defines the functions of a "digital safe component". Its role is to provide technical proof regarding the date and integrity of each item, an essential condition for its probative value in case of dispute.
Digital safe deposit box or electronic archiving: what is the difference?
The two notions are close but distinct. The digital safe (standard NF Z42-020) is a component: it seals and preserves individual documents with proof of integrity and time-stamping. The electronic archiving system, or SAE (standard NF Z42-013), is a broader organisational and technical set, which manages the entire lifecycle of the archive: submission, classification plan, final disposition and traceability.
In practice, a digital safe is often the preservation component with probative value at the heart of an archiving project. To learn more, consult our electronic archiving guide and the electronic archiving entry in the glossary.
Probative value: what makes the difference
The probative value is the capacity of a document to serve as evidence. It rests on four technical guarantees provided at the time of deposit.
Integrity fingerprint
A digital fingerprint (SHA-256) is calculated on entry: any subsequent modification, even of a single character, becomes detectable.
Qualified timestamping
A qualified timestamp token (eIDAS) attests to a certain date, which is enforceable against third parties.
Immutability (WORM)
The document is locked for write-once access: it cannot be modified or deleted before the end of its retention period.
Guaranteed restitution
You can retrieve your documents at any time, without dependence on a proprietary format.
The normative framework: NF Z42-020, NF Z42-013 and eIDAS
Three references structure preservation with probative value. The NF Z42-020 standard specifies the functions of a digital safe component; the NF Z42-013 standard (incorporated into ISO 14641) governs the electronic archiving system as a whole.
At European level, the eIDAS regulation defines qualified trust services, including qualified electronic time-stamping, which confers a certain date enforceable against third parties. The eIDAS 2.0 revision extends this framework to the European digital identity wallet. Together, these texts establish the legal value of preserved documents.
When to use a digital safe?
The need arises as soon as a document must be preserved in an enforceable manner, for a legal or contractual period. The safe thus complements an electronic signature approach or HR digitalisation. A few common examples:
- Salary slips — the employer must provide a secure storage space to the employee (Labour Code).
- Signed contracts — preserve an electronic contract with probative value throughout its engagement period.
- Invoices — archiving with probative value mandated by the electronic invoicing reform.
- Personal documents — diplomas, deeds, supporting documents stored securely and accessible for life.
Security and GDPR compliance
In a serious digital safe, each document is encrypted at rest with a key specific to the safe. Key management should ideally rely on a hardware security module (HSM), which protects cryptographic secrets against any extraction.
The preservation of personal documents falls under the GDPR: data minimisation, justified retention period, right of access and restitution. A compliant safe logs access and ensures that only the holder, or an authorised person, can view or retrieve the documents.
Digital safe or cloud storage?
A cloud storage (Drive, Dropbox…) is designed for sharing and synchronisation: files can be modified and deleted at will, without proof of their state on a given date.
A digital vault does the opposite: it seals, time-stamps and makes each document immutable. The former meets a need for convenience; the latter meets a need for proof and compliance. You can moreover verify the integrity of a signed document at any time.
How long should one keep one's documents?
The retention period depends on the nature of the document and your legal obligations. A digital safe deposit box allows you to set, for each document, a period during which it remains immutable, and then, if applicable, a controlled deletion. A few common guidelines in France:
| The document | Indicative retention period |
|---|---|
| Salary slip (employee) | until retirement, then + 3 years (lifetime recommended) |
| Invoice (customer or supplier) | 10 years |
| Commercial contract | 5 years after contract termination |
| Tax documents | Minimum 6 years |
| Personal deeds and diplomas | Lifetime |
Ready to preserve your documents with probative value?
Certyneo Vault : the digital safe for individuals and businesses.
See also our pricing and the Certyneo Vault offering.
Frequently asked questions
Is a digital safe mandatory?
It is not always mandatory, but it becomes so in fact in several cases: dematerialisation of pay slips, archiving of invoices (e-invoicing reform), preservation of contracts with probative value.
What is the difference with electronic signature?
Electronic signature creates a binding document; the digital safe then preserves it in an unalterable and enforceable manner. The two are complementary.
Are my documents encrypted?
Yes, at Certyneo each document is encrypted at rest with a key unique to your vault.
How long is a document retained?
The duration is configurable according to your legal obligations, with a default of 10 years.
Does a digital vault have legal value?
Yes. Thanks to the integrity fingerprint and qualified time-stamping, a document stored in a compliant digital vault has probative value: it can be produced as evidence, and its date as well as its integrity are enforceable against third parties.
What is the difference between a digital vault and a SAE?
The digital vault (NF Z42-020) is the component that seals and preserves a document of probative value. The SAE (NF Z42-013) is the complete archival system that organises the entire documentary life cycle. The former is often a building block of the latter.
What is the NF Z42-020 standard?
It is the French standard that defines the expected functions of a digital safe deposit box component: deposit with fingerprint, timestamping, immutable preservation (WORM), traceability and guaranteed restitution.
How do I retrieve my documents?
Restitution is guaranteed at any time, in an open format and without dependence on a proprietary tool, with the file and its associated proofs (fingerprint, timestamping token).
Also read
Recommended articles
Digital payslip: legal value and retention
The digital payslip has the same legal value as its paper equivalent, provided strict retention rules are followed. Discover what digitalisation implies for your HR obligations in 2026.
Digital Safe: Complete Definition 2026
What is a digital safe and how does it differ from simple electronic filing? Discover the complete definition, legal obligations and concrete use cases.
Duration of storage for electronically signed documents in France...
Conserving your electronically signed documents in France is easy! Discover how the eIDAS regulation and GDPR help you store your documents legally. Save time and reduce legal risks with Certyneo.