Making e-mails simply secure
Email encryption and digital signatures protect your data
Encrypt emails with REDDOXX
Emails are one of the most frequently used communication channels, but often contain confidential, sensitive or personal information. At the same time, the requirements are increasing: legally due to GDPR and NIS2, practically due to targeted cyberattacks and also humanly, because business partners and customers expect secure communication today.

Whether contracts, personal data or internal planning – with MailSealer you ensure that content can only be read by the right recipient.

The REDDOXX MailSealer helps you to comply with legal requirements for the confidentiality and integrity of emails – without complex manual processes.

Every signed e-mail is marked in a forgery-proof manner. The recipient recognizes that the message is authentic and unchanged – a real signal of trust.

MailSealer encrypts automatically – without any manual intervention. The protection is integrated directly into the email flow and works independently of the client.

Secure communication signals professionalism, reliability and data protection awareness to your customers and partners – a plus point in any customer relationship.

Thanks to the central gateway integration, users do not have to do anything actively – no keys, no plug-ins, no risks from wrong clicks or forgotten steps.
E-mail encryption with REDDOXX
REDDOXX MailSealer combines email encryption, digital signatures and central control in one sophisticated solution. The system integrates smoothly into existing infrastructures and ensures security without disrupting the workflow – regardless of whether 10 or 10,000,000 emails are sent per day.

Email encryption with market standards & without effort
REDDOXX MailSealer encrypts incoming and outgoing emails fully automatically at gateway level before they leave the mail server or arrive in the recipient’s mailbox. All common standards such as S/MIME and OpenPGP are supported. Whether personal data, contract attachments or internal communication: encryption is rule-based without the user having to take any action.
And best of all, the entire encryption process runs in the background – no clicking, no additional software, no disruptions to the workflow.
Digital signature – verify the sender, prevent tampering
With REDDOXX MailSealer, outgoing emails can be digitally signed automatically. This makes it recognizable for the recipient, that the message is authentic and has been transmitted unchanged – including metadata and attachments. The digital signature creates trust in business e-mail traffic and protects against manipulation or identity misuse.
And the best thing is that recipients can see at first glance that the e-mail really comes from you – a clear advantage in terms of trust, especially in security-critical industries.


Central key management – no more certificate chaos
Keys, certificates and encryption rules are managed centrally in REDDOXX MailSealer. This relieves your IT department and avoids typical sources of error due to decentralized, user-dependent administration. Public keys from external partners can also be obtained or stored automatically.
And best of all: even if communication partners, certificates or processes change – MailSealer remains flexible and takes care of the administration for you.
Encrypting emails also works without certificates
Not every business partner uses S/MIME or PGP and yet sensitive content still needs to be protected. This is exactly why REDDOXX MailSealer can be combined with our second solution for email encryption REDDCRYPT. Emails sent to recipients without an existing certificate can also be encrypted and the recipient can then easily decrypt the email in a web portal, on their smartphone or via an Outlook plugin.
And best of all, you can use it to encrypt any email – regardless of whether the other person has a REDDCRYPT account or not. This means that secure communication is finally suitable for everyday use.

But our encryption can do even more!
With MailSealer, you are not just opting for secure email encryption, but for a system that fits seamlessly into your processes and grows with your requirements. From automated rules and central administration to flexible integration into existing infrastructures, MailSealer offers everything you need for future-proof email communication.
MailSealer works entirely on the server side – without software installation on clients or end devices.
Regardless of whether you use Microsoft 365, Exchange, Lotus Notes or other systems – MailSealer integrates seamlessly.
Define encryption and signature guidelines centrally – e.g. by sender, recipient or domain.
Full support for common encryption and signature standards such as X.509, S/MIME and OpenPGP.
Before sending, the MailSealer can check whether a certificate is available on the LDAP server of the communication partner (e.g. employment agency).
Signed and encrypted emails can be fully archived and retrieved with REDDOXX MailDepot thanks to the internal interface.
Who is REDDOXX MailSealer suitable for?
REDDOXX MailSealer was deliberately developed so that it can be used efficiently in smaller companies with just a few mailboxes as well as in large IT structures with thousands of users. The solution integrates seamlessly into existing e-mail systems and can be used productively in a very short time – without complex preparations or time-consuming conversions.
Small companies benefit from automated encryption that is easy to set up and works without ongoing administration. Large organizations get a powerful system that integrates into existing security architectures, offers central management functions and meets the highest data protection and compliance requirements.
Communicate securely – without any specialist technical knowledge. MailSealer is easy to integrate and works without ongoing maintenance.
Growing e-mail traffic, increasing security requirements? MailSealer protects sensitive content and automates the encryption process.
Encryption for thousands of mailboxes, centralized key management and compliance at the highest level – MailSealer adapts to your structure.
Whether it’s a law firm, clinic, administration or educational institution – MailSealer is the secure solution for sending emails wherever confidentiality counts.
How REDDOXX MailSealer works
REDDOXX MailSealer can be quickly and easily integrated into your existing IT environment. The solution centrally handles the signing and encryption of your emails – fully automatically and user-friendly. This allows you to communicate reliably and in compliance with GDPR, without additional effort for your users.
The REDDOXX Appliance is a virtual machine and can be installed under almost any hypervisor. VMware, Hyper-V, Citrix XEN, KVM, Proxmox, Nutanix AHV or Virtual Box are supported, among others.
No. MailSealer works independently of the mail server used and integrates seamlessly into your existing environment – whether Exchange, Microsoft 365, Postfix, Lotus Notes or other systems.
The virtual appliance is usually installed and configured within 2-4 hours. After the basic configuration, you can start using email encryption immediately.
Yes, MailSealer supports you in protecting sensitive data during communication transfer.
With REDDOXX MailSealer you can encrypt emails with OpenPGP and S/MIME. In addition, REDDCRYPT provides a solution if the remote peer does not have any certificates.
Yes, thanks to the integrated REDDCRYPT technology, REDDOXX MailSealer also works without classic S/MIME or PGP certificates. The system automatically generates the necessary keys and offers recipients without their own solution a secure web portal for message access. If the remote station has its own REDDCRYPT license, encryption and decryption can also be carried out via an Outlook plugin.
Yes! In this case, the message is automatically delivered via the REDDCRYPT web portal. The recipient receives an e-mail notification with a link that they can use to decrypt the message using a password, read it securely and reply to it – without any additional software.
No, the entire process runs fully automatically on the server side. Your employees write and send emails as usual – REDDOXX MailSealer takes care of the signature and encryption in the background.
No problem. REDDOXX MailSealer acts as an independent SMTP gateway in front of your email server and can continue to be used seamlessly.
Yes, the REDDOXX MailSealer supports the secure exchange of EDIFACT data via these standards. You can find more information here.
Yes, existing S/MIME or PGP certificates can be easily imported and centrally managed. This means you can continue to use existing infrastructures and integrate them seamlessly into REDDOXX.