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 evidentiary 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 protects your electronic documents reliably and durably. Unlike a hard drive or standard cloud storage, it guarantees that each document remains unalterable, time-stamped and retrievable throughout its entire retention period.
In France, it complies with a precise regulatory framework: the NF Z42-020 standard defines the functions of a "digital safe component". Its role is to provide technical evidence regarding the date and integrity of each document, an essential condition for its evidentiary value in the event of dispute.
Digital safe deposit box or electronic archiving: what's the difference?
The two notions are close 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 organisational and technical system that manages the entire lifecycle of the archive: deposit, classification plan, final disposal and traceability.
In practice, a digital safe is often the evidential preservation brick at the heart of an archiving project. To learn more, consult our electronic archiving guide and the electronic archiving glossary entry.
Evidentiary value: what makes the difference
The evidentiary value is the capacity of a document to serve as proof. 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 time-stamping
A qualified time-stamping token (eIDAS) attests to a certain date, which is binding against third parties.
Immutability (WORM)
The document is locked for write-once: it cannot be modified or deleted before the end of its retention period.
Guaranteed restitution
You retrieve your documents at any time, with no dependence on a proprietary format.
The regulatory framework: NF Z42-020, NF Z42-013 and eIDAS
Three references structure evidential preservation. The NF Z42-020 standard specifies the functions of a digital safe component; the NF Z42-013 standard (incorporated in ISO 14641) governs the electronic archiving system as a whole.
At European level, the eIDAS regulation defines qualified trust services, including qualified electronic timestamping, 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 provisions establish the legal value of preserved documents.
When should you use a digital safe?
The need arises as soon as a document must be retained in an enforceable manner, for a legal or contractual duration. The digital safe thus complements a electronic signature or HR digitalisation approach. A few common examples:
- Payslips — the employer must provide a secure storage space to the employee (Labour Code).
- Signed contracts — retain an electronic contract with probative value for the duration of its commitment.
- Invoices — archiving with probative value imposed by the electronic invoicing reform.
- Personal documents — diplomas, deeds, supporting documents securely retained 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 ideally relies 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 all access and ensures that only the holder, or an authorised person, can view or retrieve the documents.
Digital safe or cloud storage?
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 safe 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 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 period during which it remains immutable, then, if necessary, a controlled deletion. A few common guidelines in France:
| The document | Indicative retention period |
|---|---|
| Payslip (employee) | until retirement, then + 3 years (lifetime recommended) |
| Invoice (customer or supplier) | 10 years |
| Commercial contract | 5 years after the end of the contract |
| Tax documents | Minimum 6 years |
| Personal deeds and diplomas | For life |
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Frequently asked questions
Is a digital safe compulsory?
It is not always compulsory, but it becomes so in practice in several cases: dematerialisation of payslips, invoice archiving (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 specific to your safe deposit box.
How long is a document retained?
The duration is configurable according to your legal obligations, with a default of 10 years.
Does a digital safe have legal value?
Yes. Thanks to the integrity fingerprint and qualified time-stamping, a document kept in a compliant digital safe has probative value: it can be produced as evidence, and its date as well as its integrity can be enforced against third parties.
What is the difference between a digital safe and a RMS?
The digital safe (NF Z42-020) is the component that seals and preserves a document with probative value. The RMS (NF Z42-013) is the complete archiving system that organises the entire document lifecycle. 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: deposit with fingerprint, timestamping, immutable storage (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 a proprietary tool, with the file and its associated evidence (fingerprint, timestamp token).
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