How do I verify a forwarded email?

Ask the mailbox owner to export the original email as a .eml file, then upload it to selfcheck.email. The DKIM signature on the original indicates whether the content is unchanged.

What does DKIM verification establish?

A valid DKIM signature establishes that the email content has not been altered since the sender's mail server signed it. It does not establish that the content is true or that a specific person wrote it.

Yes. You can verify up to 5 emails per hour without an account. Free accounts get 5 cases per month with timestamped PDF reports.

Does SelfCheck store my email?

No. The email file is processed in memory and deleted immediately. Only cryptographic hashes and the PDF report are retained.

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DKIM explained for lawyers and compliance teams

4 min

The wax seal analogy

Think of DKIM as a wax seal on a letter. When a mail server sends an email, it presses a seal onto the message — a cryptographic signature that covers the text and key details (sender, subject, date). If someone opens the letter and changes even one word, the seal breaks.

When SelfCheck verifies an email, it checks whether the seal is still intact.

How it works (without the maths)

1.Signing: The sender's mail server creates a unique fingerprint (hash) of the email body and selected headers. It encrypts this fingerprint with a private key. The encrypted fingerprint is added to the email as an invisible DKIM-Signature header.

2.Verification: Anyone with access to the original email can look up the sender's public key (published in DNS) and decrypt the fingerprint. They then compute their own fingerprint of the email and compare the two. If they match, the content is unchanged.

3.The three verdicts: If the fingerprints match → Verified. If the key cannot be found (often rotated) → Inconclusive. If the fingerprints differ → Mismatch.

What DKIM establishes

·The signed content has not been altered since the mail server processed it

·The email was handled by a server authorised to send on behalf of that domain

·Which specific headers (From, Subject, Date) were included in the signature

What DKIM does not establish

·That the person named in "From" actually wrote the email

·That the email's content is true or accurate

·That the sending account was not compromised

·That unsigned parts (like some attachments) have not been changed

Why this matters for your work

If you work in law, compliance, or fraud investigation, you often need to determine whether a forwarded email is genuine. A forward strips the DKIM signature, so you cannot verify a forwarded copy — you need the original from the mailbox. SelfCheck makes this process straightforward: the owner exports the .eml file, uploads it, and you get a clear verdict with stated limits.

Try it now

Drop an .eml file on the homepage for an instant verification — no account needed.

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