Doichain LVC, Dr. Grass-Strasse 12, LIE-9490 Vaduz

Problems and solutions

Presentation of the problem and challenge

E-mails are an excellent medium for marketing and selling campaigns. These campaigns get more successful, the more people it reaches. Hence the large temptation to send as much e-mails as possible, even if you cant prove without a doubt, if every address owner actually did agree to receive this advertisment. The efficiency of this medium and the cheap price to send e-mails, caused a flood of massive amounts of e-mails.

As a result rules were determined, which only allow the delivery of promotional mails to a receiver, who explicitly gave the sender a permission. Usually this permission is granted via a Double Opt-in procedure. The e-mail address, who will get the advertisment, has to confirm this permission additionally.

The problem is, that it isn´t possible for an independent third party, to check a permission. Both the provider of the mailserver and the receiver of the mail have to trust the entity, which manages the permissions, that it reliably documents a potential withdrawal of a permission.

Campaigns, that violate these rules, are marked as SPAM. Multiple methods were developed in order to defend against SPAM. But to this day no system was created, which reliably differentiates between desired and non-desired mails. In conclusion some of the desirable mails still land in the SPAM-folder or don´t even reach the receiver and SPAM-mails sometimes reach the inbox. With the help of the Doichain this problem can be reliably solved, while also complying with all data protection regulations.

Solutions with the help of blockchain

The owner of an e-mail-address fills this in a web form and confirms the advertisment permission, by sending this form.


The address generator sends the e-mail-address to a decentralized app (DApp) of the respective mailserver provider.
A corresponding Single Opt-in record is being made in the Doichain.


The DApp of the mailserver provider sends a e-mail to the receiver, which demands to confirm the permission with a click on a link.


The e-mail receiver clicks on the DOI link


The DApp of the mailserver provider confirms the Single Opt-In record in the blockchain with a signature. As a result the SOI becomes a DOI, in other words it becomes a valid permission, confirmed by the e-mail receiver.

Goals, risks and consequences
for the affected parties
Owner of a e-mail-address

Goal: Manage permissions for advertisments whenever you want. Reliably document and execute a withdrawal of a permission.

Risk: An unsubscription of a newsletter is documented as a sign, that the mailbox is active. As a result the e-mail-address is counted as valueable and sellable.

Consequence: Even more e-mail spam


Goal: Proper DOI confirmed permissions from consumers, who want to receive mails with advertisment.

Risk: The lead generator provides forged DOI permissions.

Consequence: The current database is supplied with SPAM Traps, which significantly damages the reputation and hampers or even renders e-mail marketing impossible.

E-mail service provider

Goal: Flawless delivery of e-mails.

Risk: Damage to reputation through address lists, which are contaminated with SPAM-Traps.

Mailserver provider and internet service provider

Goal: To meet customer expectations, valid e-mails have to reach the inbox, while spam mails should be sorted into the spam folder or get blocked completely.

Risk: Mails, which are desired by the receiver, are blocked and never reach the inbox.

Address generator

Goal: Generate as much permissions as possible for their sponsors (advertiser), who want to send advertisment via e-mail.


Goal: Definite proof, if a permission for advertising is given at the exact moment of delivery.