Whatever level you're on now, the next step is the same: issue (or re-issue) the document through TRUE. That alone makes the document tamper-proof. When you send a document through TRUE, a SHA-256 hash of the file is written to a blockchain. The proof is permanent, independent, and exists for the lifetime of the document, and that alone makes it tamper-proof. TRUE can also embed a qualified electronic signature (QES) from an accredited EU trust service provider, tying the document to a verified signer identity, the strongest combination of proofs a document can carry. Recipients paste the document URL or upload the PDF at TRUE Verify. They see the tamper-proof verdict confirmed in seconds, valid indefinitely, with no account or API key required.

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Security level guide

How to improve your security level

Every document we verify gets one of five security levels. Signed + Secured and Secured are tamper-proof and verifiable for life. Below: what each level means, and how to go up a level if you're not there yet.

Security levels, explained

Signed + Secured and Secured both mean your document is tamper-proof and verifiable for life. Signed is neutral. Unsecured and No Origin have gaps worth closing.

Strong

Signed + Secured

Signed and tamper-proof

A qualified digital signature combined with a permanent blockchain record. The strongest verification possible.

BlockchaineIDASDigital signature

Already at the top: both signed and secured, tamper-proof for life. No gaps.

Secured

Tamper-proof on blockchain

Document hash matches the on-chain record. Permanent, tamper-proof proof that cannot be altered or removed.

BlockchainDigital signature

Already tamper-proof on the blockchain. Adding an eIDAS qualified signature would also tie the document to a verified signer identity, taking it up one more level.

How to improve: Add an eIDAS qualified signature through TRUE to also tie the document to a verified signer identity. Level I and Level II are both tamper-proof and verifiable for life.

Neutral

Signed

Has a verified digital signature

Requires the original file. Cannot be verified online. Certificate can expire or be revoked. No public record of existence.

Digital signature

Missing: a blockchain anchor. The digital signature proves the file has not been changed since it was signed, but proof depends on the signing certificate chain staying valid. If the CA revokes the cert, the proof is gone.

How to improve: Anchor the document hash to a blockchain. TRUE issues documents with blockchain proof built in, making them tamper-proof: Level II by default, Level I if you also include eIDAS signing.

Weak

Unsecured

Could be fabricated or changed

The document exists only in the issuer's own database. It can be edited, removed, or fabricated at any time. No independent or cryptographic proof.

Issuer database only

Missing: both a blockchain record and a cryptographic signature. The only proof is the issuer's own database, which they can edit, remove, or take offline at any time.

How to improve: Issue through TRUE. Every TRUE-issued credential gets a blockchain record and can include an eIDAS digital signature, tamper-proof and verifiable for life.

No Origin - No Security

Nothing backs up this document

No blockchain record, digital signature, or issuer confirmation found. Anyone could have created it.

No proof found

Missing: everything. No digital signature, no blockchain record, no issuer confirmation. A standard document file can be fabricated or altered in minutes using free tools.

How to improve: Issue through TRUE. TRUE-issued documents have blockchain proof anchored at the moment of issue: permanent, independent, and tamper-proof for the lifetime of the credential.

Going up a level

Whatever level you're on now, the next step is the same: issue (or re-issue) the document through TRUE. That alone makes the document tamper-proof.

Issue through TRUE

When you send a document through TRUE, a SHA-256 hash of the file is written to a blockchain. The proof is permanent, independent, and exists for the lifetime of the document, and that alone makes it tamper-proof.

Optionally add an eIDAS signature

TRUE can also embed a qualified electronic signature (QES) from an accredited EU trust service provider, tying the document to a verified signer identity, the strongest combination of proofs a document can carry.

Verify instantly, forever

Recipients paste the document URL or upload the PDF at TRUE Verify. They see the tamper-proof verdict confirmed in seconds, valid indefinitely, with no account or API key required.

Why blockchain + eIDAS makes documents tamper-proof

A blockchain record means the document's fingerprint is locked to a specific transaction on a public ledger. Anyone, not just TRUE, can verify it independently, at any time, using nothing but the file and a blockchain explorer. That alone is Level II.

An eIDAS Qualified Electronic Signature adds a second layer: it ties the document to a verified signer identity, the time of signing, and an accredited certificate authority. Combined with the blockchain anchor, that's Level I.

Either way, a tamper-proof document can be verified online or offline, today or in 20 years, without depending on any single server, company, or certificate authority staying online.

Tamper-proof: Signed + Secured

Diploma in Computer Science

SignerKTH Royal Institute of Technology
Issuer CABuypass Class 3 CA 3
Signed2026-04-15 09:32 UTC
Policy OID0.4.0.194112.1.2 (QCP-n-qscd)
Blockchain Polygon, block 78,491,233

Want your documents to be tamper-proof?

Issue credentials on TRUE and every diploma, certificate and badge your organisation issues lands at Signed + Secured or Secured, permanently, for free, for every recipient.

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