Features

Security

This page describes what Signater does to protect your documents, with the precision a legal or security team expects — and nothing beyond what the platform delivers.

From the connection to the stored file: TLS in transit, documents encrypted and replicated across multiple zones, PAdES sealing on the signed PDF, Signater's timestamp and an audit trail that only grows.

Platform foundations

The most sophisticated signing feature is worth little on a fragile platform. These are the base protections, from the connection to the database.

TLS in transit, with HSTS

Every access, from the browser or the API, goes through HTTPS/TLS at the edge, with HSTS preventing any fallback to unencrypted HTTP.

Files encrypted at rest

Documents live in object storage, encrypted with provider-managed AES-256 and replicated across zones and geographic regions.

AES-256-GCM for secrets

API tokens, MFA codes, digital certificate passwords and SMTP credentials are encrypted at rest, with a random nonce per value.

Passwords with PBKDF2

The database stores only a PBKDF2 derivation with an individual salt; the password itself is never stored.

2FA with an authenticator app

A TOTP second factor for whoever operates the account, with recovery codes so you are not locked out when switching devices.

Turnstile against automation

The Cloudflare Turnstile challenge blocks bots on the authentication screens, without asking real people to decipher image puzzles.

Storage

Files stored with encryption and redundancy

Documents live in object storage with provider-managed AES-256 encryption at rest — no file is ever written unencrypted.

Every file is automatically replicated across multiple devices, availability zones and geographic regions: a hardware failure never compromises your documents.

Deletions go through the trash, with restore available to the account owner before permanent removal.

Availability and durability

A 99.9% SLA and files that don't get lost

Storage operates under a 99.9% availability Service Level Agreement (SLA).

Files are replicated by the provider across multiple geographic regions, with designed durability of 99.999999999% per year — eleven nines. In practice, losing a file is a statistically negligible event.

Additional backup layers, in a separate region, protect documents beyond the provider's replication.

Signature standard

PAdES signatures embedded in the PDF

The cryptographic signature lives inside the file itself, in the PAdES standard, recognizable by mainstream signature validators. The document carries its own proof instead of depending on an external registry.

After signing, the document is sealed: any later change breaks the seal and is flagged by PDF readers, such as Adobe Reader.

The signature hash uses SHA-256, SHA-384 or SHA-512, and the certificate of completion records the SHA-256 of each file for integrity checks.

Moment of signing

A timestamp on every signature

Along with the signature, the document receives a timestamp issued by Signater as a Timestamping Authority: cryptographic proof of when the signature happened.

The recorded moment no longer depends on the clock of the signer's computer. If someone questions the date of a contract, Signater's timestamp cryptographically attests the exact moment — verifiable in the document itself.

Long-term validation

Valid today, verifiable years from now

Every digital signature is checked against a certificate, and certificates expire. Without preparation, validating an old document can fail years later, even if the signature was valid on the day.

With long-term validation (LTV), the document embeds the complete certificate chain and the revocation data in force at the moment of signing. The proof travels inside the file and does not depend on external lookups in the future.

Evidence

An immutable audit trail

Every action on the envelope becomes a new record: nothing is edited, nothing is deleted. The trail only grows, and that is what makes it reliable as evidence.

The record is forensic: IP address, geolocation and device for every event, plus every MFA attempt, including the incorrect ones. Whoever got the code wrong before getting it right left that in writing.

At the end, the full history is consolidated in the certificate of completion that accompanies the envelope.

Frequently asked questions

Are the signatures legally valid?

Yes. Electronic signature laws such as the U.S. ESIGN Act and the EU's eIDAS regulation recognize electronic signatures; in Brazil, MP 2,200-2/2001 and Law 14,063/2020 do the same. Signater produces an advanced electronic signature based on a digital certificate: signer binding, multi-factor authentication, hash-based integrity, document sealing and an audit trail of the act.

What is the difference between an advanced and a qualified signature?

The advanced signature identifies the signer and guarantees document integrity through cryptographic means, without requiring them to hold an ICP-Brasil certificate. The qualified signature is made with the signer's own ICP-Brasil certificate.

Do you need a qualified electronic signature?

Signater produces an advanced electronic signature based on a digital certificate, in the PAdES standard. When the signer signs with their own ICP-Brasil certificate (A1), with a qualified timestamp and long-term validation, the signature meets the requirements of a qualified electronic signature.

What is a timestamp (TSA)?

It is cryptographic proof issued by a Timestamping Authority attesting the exact moment the signature existed. The document date stops depending on the clock of the signer's computer.

What is LTV and when do I need it?

LTV (long-term validation) embeds the certificate chain and the revocation data from the moment of signing into the document. Without it, validation can fail once the signer's certificate expires. It is worth it for documents that need to stay verifiable for years, such as long-term contracts and corporate records.

How are files stored?

Documents live in object storage with provider-managed AES-256 encryption at rest, replicated across availability zones and geographic regions, under a 99.9% availability SLA with 99.999999999% designed annual durability and additional backup layers. Deletions go through the trash, with restore available to the account owner.

How do you store passwords and secrets?

Access passwords are never kept in plain text: we store a PBKDF2 derivation with an individual salt per password. Secrets the platform needs to read back, such as API tokens, MFA codes, digital certificate passwords and SMTP credentials, are encrypted with AES-256-GCM, with a random nonce per value.

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