Exchange Digital Signatures - How It Works

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Exchange Digital Signatures - How It Works

S/MIME (Secure/Multipurpose Internet Mail Extensions) is a standard for digital signatures and encryption of emails. With S/MIME, you can secure your email communication and provide digital proof of your identity.

S/MIME is available free of charge in all tariffs.

What can S/MIME do for you?

Digital Signature: Proves that an email really comes from you and hasn't been changed in transit
Encryption: Ensures that only the intended recipient can read your email
Authenticity: Your contact immediately sees that the message comes from you
Privacy: Prevents unauthorized persons from reading your private emails

How does S/MIME work?

The principle: S/MIME uses two keys:

Private Key: Only you know this key. It is stored encrypted in your certificate (.pfx or .p12 file)
Public Key: This key is public. Your contacts use it to communicate with you in encrypted form

The S/MIME Process - Step by Step

Phase 1: SETUP (only once)

You import your certificate with private key
eclipso Mail Europe stores the private key securely
✅ You are ready to sign

Phase 2: EXCHANGE (required with each new partner)

You send a signed email to your contact
Your public key is automatically sent with it
Contact receives your public key and saves it
Contact sends signed reply back
You receive contact's public key
✅ Exchange complete!

Phase 3: ENCRYPTION (after successful exchange)

You can now send encrypted
You use: Contact's public key (for encryption)
Contact uses: Their private key (for decryption)
✅ Only contact can read email!

Important Concepts

⚠️ CORRECT ORDER:

❌ WRONG: Try to encrypt immediately
✅ CORRECT: Sign first, wait for exchange, then encrypt

⚠️ BOTH SIDES NEED A CERTIFICATE:

❌ WRONG: Only you have a certificate
✅ CORRECT: Both sides must have imported a certificate

⚠️ PUBLIC KEYS MUST BE EXCHANGED:

❌ WRONG: They exchange automatically
✅ CORRECT: They are exchanged through signed emails

Supported Applications

S/MIME is a standard and works with many email programs:

Web Browser (eclipso Mail Europe web interface)
Microsoft Outlook
Apple Mail
Mozilla Thunderbird
Other standard email clients

Next Steps

Ready to use S/MIME? Then follow these guides:

Exchange Digital Signatures - How It Works