The digital safe, explained simply
A digital safe is not simply a storage space: it is a preservation system 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 reliably and durably protects your electronic documents. Unlike a hard drive or standard cloud storage, it guarantees that every document remains unalterable, time-stamped, and retrievable throughout its 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 of the date and integrity of each document, an essential condition for its probative value in case of dispute.
Digital safe deposit box or electronic archiving: what's the difference?
The two concepts are closely related but distinct. The digital safe (NF Z42-020 standard) is a component: it seals and preserves individual documents with proof of integrity and timestamping. The electronic archiving system, or EAS (NF Z42-013 standard), is a broader organizational and technical system that manages the entire lifecycle of archives: submission, classification plan, final disposition, and traceability.
In practice, a digital safe is often the probative-value preservation component at the core of an archiving project. To learn more, consult our electronic archiving guide and the electronic archiving glossary entry.
Probative value: what makes the difference
The probative value is the ability of a document to serve as evidence. It is based on four technical guarantees provided at the time of deposit.
Integrity fingerprint
A digital fingerprint (SHA-256) is calculated at entry: any subsequent modification, even of a single character, becomes detectable.
Qualified timestamping
A qualified timestamping token (eIDAS) certifies a certain date, binding on 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 retrieval
You can retrieve your documents at any time, without dependence on a proprietary format.
The regulatory framework: NF Z42-020, NF Z42-013, and eIDAS
Three references structure probative-value preservation. 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 the European level, the eIDAS regulation defines qualified trust services, including qualified electronic timestamping, which provides a certified date that can be enforced against third parties. The eIDAS 2.0 revision extends this framework to the European digital identity wallet. Together, these texts establish the legal validity of preserved documents.
When should you use a digital safe?
The need arises whenever a document must be preserved in an enforceable manner, for a legal or contractual duration. The digital safe thus complements an approach to electronic signature or HR digitalization. A few common examples:
- Pay stubs — the employer must offer the employee a secure storage space (Labor Code).
- Signed contracts — preserve an electronic contract with evidentiary value for the duration of its commitment.
- Invoices — archiving with evidentiary value required by the electronic invoicing reform.
- Personal Documents — diplomas, certificates, proof documents securely preserved and accessible for life.
Security and GDPR compliance
In a serious digital safe, each document is encrypted at rest with a key unique to the safe. Key management ideally relies on a hardware security module (HSM), which protects cryptographic secrets against any extraction.
The preservation of personal documents falls under GDPR requirements: data minimization, justified retention duration, access and restitution rights. A compliant safe logs all access and ensures that only the account holder, or an authorized person, can view or retrieve the documents.
Digital safe or cloud storage?
Cloud storage (Drive, Dropbox…) is designed for sharing and syncing: files can be modified and deleted at will, with no proof of their state on a given date.
A digital vault does the opposite: it seals, timestamps and makes each document immutable. The first meets a need for convenience; the second for proof and compliance. You can even verify the integrity of a signed document at any time.
How long should you keep your documents?
The retention period depends on the nature of the document and your legal obligations. A digital safe allows you to set, for each document, a duration during which it remains immutable, and then, if applicable, a controlled deletion. Here are some common benchmarks in France:
| Document | Recommended retention period |
|---|---|
| Pay stub (employee) | until retirement, then + 3 years (lifetime recommended) |
| Invoice (customer or supplier) | 10 years |
| Commercial contract | 5 years after contract end |
| Tax documents | Minimum 6 years |
| Personal deeds and diplomas | Lifetime |
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Frequently asked questions
Is a digital safe mandatory?
It is not always mandatory, but it becomes so in practice in several cases: paperless payroll slips, invoice archiving (e-invoicing reform), preservation of legally binding contracts.
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 specific to your vault.
How long is a document kept?
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 timestamp, 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 with probative value. The SAE (NF Z42-013) is the complete archiving system that manages the entire document lifecycle. The former is often a component 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: deposit with fingerprint, timestamping, immutable preservation (WORM), traceability, and guaranteed retrieval.
How do I retrieve my documents?
Retrieval is guaranteed at any time, in an open format and without dependence on proprietary software, with the file and its associated proof documents (fingerprint, timestamp token).
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