all-in-one privacy solution":["Proton Unlimited jest wszystko-w-jednym rozwiązaniem prywatności"],"Black Friday":["Czarny Piątek"],"No ads. Privacy by default.":["Brak reklam. Prywatność w standardzie."],"People before profits":["Ludzie przed zyskiem"],"Security through transparency":["Bezpieczeństwo dzięki przejrzystości"],"The best Proton Mail ${ BLACK_FRIDAY } deals":["Najlepsze oferty Proton Mail ${ BLACK_FRIDAY }"],"The world’s only community- supported email service":["Jedyna na świecie społecznościowa- obsługiwana usługa e-mail"]},"specialoffer:limited":{"${ hours } hour":["${ hours } godzina","${ hours } godziny","${ hours } godzin","${ hours } godziny"],"${ hoursLeft }, ${ minutesLeft } and ${ secondsLeft } left":["Pozostało: ${ hoursLeft }, ${ minutesLeft } i ${ secondsLeft }"],"${ minutes } minute":["${ minutes } minuta","${ minutes } minuty","${ minutes } minut","${ minutes } minuty"],"${ seconds } second":["${ seconds } sekunda","${ seconds } sekundy","${ seconds } sekund","${ seconds } sekundy"],"Limited time offer":["Oferta ograniczona czasowo"]},"specialoffer:listitem":{"Create multiple addresses":["Utwórz wiele adresów"],"Hide-my-email aliases":["Aliasy hide-my-email"],"Quickly unsubscribe from newsletters":["Szybko anuluj subskrypcję biuletynów"],"Use your own domain name":["Korzystaj z własnej nazwy domeny"]},"specialoffer:logos":{"As featured in":["Opinie naszych klientów"]},"specialoffer:metadescription":{"Get an encrypted email that protects your privacy":["Uzyskaj zaszyfrowaną usługę e-mail, która chroni Twoją prywatność"]},"specialoffer:metatitle":{"Proton Mail Black Friday Sale - Up to 40% off":["Wyprzedaż Proton Mail z okazji Czarnego Piątku – uzyskaj do 40% zniżki"]},"specialoffer:newmetadescription":{"Get up to 40% off Proton Mail subscriptions this Black Friday. Find great deals on our secure end-to-end encrypted email plans.":["Uzyskaj do 40% zniżki na subskrypcje Proton Mail w ten Czarny Piątek. Znajdź wspaniałe oferty naszych bezpiecznych planów usługi poczty elektronicznej w szyfrowaniu end-to-end."]},"specialoffer:newmetatitle":{"Proton Mail Black Friday sale | Up to 40% off secure email":["Wyprzedaż Proton Mail z okazji Czarnego Piątku | Do 40% zniżki na bezpieczną pocztę elektroniczną"]},"specialoffer:note":{"* Billed at ${ TOTAL_SUM } for the first year":["* Płatne ${ TOTAL_SUM } za pierwszy rok"],"*Billed at ${ TOTAL_SUM } for the first 2 years":["* Płatne ${ TOTAL_SUM } za pierwsze 2 lata"],"30-day money-back guarantee":["30-dniowa gwarancja zwrotu pieniędzy"],"Billed at ${ TOTAL_SUM } for the first 2 years":["Płatne ${ TOTAL_SUM } za pierwsze 2 lata"],"Billed at ${ TOTAL_SUM } for the first year":["Płatne ${ TOTAL_SUM } za pierwszy rok"],"You save ${ SAVE_SUM }":["Oszczędzasz ${ SAVE_SUM }"]},"specialoffer:off":{"${ PERCENT_OFF } off":["-${ PERCENT_OFF }"]},"specialoffer:testimonial":{"I love my ProtonMail":["Uwielbiam ProtonMail"],"My favorite email service":["Moja ulubiona usługa e-mail"],"Thanks Proton for keeping us all safe in the complicated internet universe.":["Dziękuję Protonowi za dbanie o nasze bezpieczeństwo w skomplikowanym internetowym uniwersum."],"You get what you pay for. In the case of big tech, if you pay nothing, you get used. I quit using Gmail and switched to @ProtonMail":["Dostajesz to, za co płacisz. W przypadku przedsiębiorstw big tech, jeśli nie płacisz nic, zostaniesz wykorzystany. Przestałam korzystać z Gmail i przeniosłam się na @ProtonMail"]},"specialoffer:time":{"Days":["Dni"],"Hours":["Godz."],"Min":["Min"]},"specialoffer:title":{"And much more":["I wiele więcej"],"Safe from trackers":["Bezpieczny od elementów śledzących"],"Stay organized":["Dbaj o dobrą organizację"],"Black Friday email deals":["Oferty e-mailowe na Czarny Piątek"],"Don’t just take our word for it":["Nie musisz wierzyć nam na słowo"],"Make your inbox yours":["Spraw, aby twoja skrzynka odbiorcza była twoja"],"Our story":["Nasza historia"],"Transfer your data from Google in one click":["Przenieś dane z Google jednym kliknięciem"]},"specialoffer:tooltip":{"Access blocked content and browse privately. Includes ${ TOTAL_VPN_SERVERS }+ servers in ${ TOTAL_VPN_COUNTRIES }+ countries, connect up to 10 devices, access worldwide streaming services, malware and ad-blocker, and more.":["Uzyskaj dostęp do zablokowanych treści i przeglądaj prywatnie Internet. Obejmuje ponad ${ TOTAL_VPN_SERVERS } serwerów w ponad ${ TOTAL_VPN_COUNTRIES } krajach z możliwością połączenia do 10 urządzeń, a także dostęp do globalnych usług streamingu, blokadę reklam, złośliwego oprogramowania i wiele więcej."],"Easily share your calendar with your family, friends or colleagues, and view external calendars.":["Łatwo udostępniaj swój kalendarz rodzinie, znajomym oraz współpracownikom i wyświetla kalendarze zewnętrzne."],"Includes support for 1 custom email domain, 10 email addresses, 10 hide-my-email aliases, calendar sharing, and more.":["Zawiera obsługę 1 niestandardowej domeny e-mail, 10 adresów e-mail, 10 aliasów hide-my-email, udostępnianie kalendarza i nie tylko."],"Includes support for 3 custom email domains, 15 email addresses, unlimited hide-my-email aliases, calendar sharing, and more.":["Obejmuje obsługę 3 niestandardowych domen e-mail, 15 adresów e-mail, nielimitowane aliasy hide-my-email, udostępnianie kalendarza i nie tylko."],"Manage up to 25 calendars, mobile apps, secured with end-to-end encryption, 1-click calendar import from Google, and more.":["Zarządzanie nawet 25 kalendarzami, aplikacje mobilne, bezpieczne szyfrowanie metodą end-to-end, importowanie kalendarza za pomocą jednego kliknięcia z Google i więcej."]},"Status banner":{"Learn more":["Dowiedz się więcej"],"Please note that at the moment we are experiencing issues with the ${ issues[0] } service.":["Uwaga: obecnie występują problemy z usługą ${ issues[0] }."],"We are experiencing issues with one or more services at the moment.":["Mamy problemy z co najmniej jedną usługą."]},"Status Banner":{"At the moment we are experiencing issues with the Proton VPN service":["W tej chwili mamy problemy z usługą Proton VPN"],"Learn more":["Dowiedz się więcej"]},"steps":{"Step":["Krok"]},"suggestions":{"Suggestions":["Sugestie"]},"Support":{"Sub category":["Podkategoria","Podkategorie","Podkategorii","Podkategorii"]},"Support article":{"${ readingTime } min":["${ readingTime } min","${ readingTime } min","${ readingTime } min","${ readingTime } min"],"Category":["Kategoria","Kategorie","Kategorii","Kategorii"],"Didn’t find what you were looking for?":["Nie znaleziono szukanej frazy?"],"General contact":["Skontaktuj się, wykorzystując ogólne zapytanie"],"Get help":["Uzyskaj pomoc"],"Legal contact":["Skontaktuj się z działem prawnym"],"Media contact":["Skontaktuj się z zespołem medialnym"],"Partnerships contact":["Skontaktuj się z zespołem ds. partnerstwa"],"Reading":["Odczytywanie"]},"Support Form Platform option":{"VPN for Android TV":["VPN dla Android TV"],"VPN for Chromebook":["VPN dla Chromebooka"]},"Support troubleshooting":{"App version":["Wersja aplikacji"],"Browser":["Przeglądarka"],"Check if this helps":["Sprawdź, czy to pomoże"],"Choose a product":["Wybierz produkt"],"Did this solve your issue?":["Czy Twój problem został rozwiązany?"],"Faster assistance is just a few clicks away":["Szybsze wsparcie uzyskasz w kilka kliknięć"],"How can we help?":["Jak możemy pomóc?"],"No, contact support":["Nie, skontaktuj się z pomocą techniczną"],"Please fill out one field after another":["Wypełnij pola jedno po drugim"],"Please make your selections":["Dokonaj wyboru"],"Proton account":["Konto Proton"],"Proton for Business":["Proton for Business"],"Thank you for your feedback":["Dziękujemy za podzielenie się opinią"],"What can we help with?":["W czym możemy pomóc?"],"Yes":["Tak"]},"support_modal_search_query":{"Search query":["Zapytanie wyszukiwania"]},"support_search_button":{"Search":["Szukaj"]},"support_search_i_am_looking_for":{"I'm looking for":["Szukam"]},"SupportForm":{"For a faster resolution, please report the issue from the Bridge app: Help > Report a problem.":["W celu szybszego rozwiązania problemu dokonaj zgłoszenia przez aplikację Bridge: Pomoc > Zgłoś problem."],"Information":["Informacje"]},"SupportForm:option":{"Account Security":["Bezpieczeństwo konta"],"Contacts":["Kontakty"],"Custom email domain":["Niestandardowa domena e-mail"],"Email delivery and Spam":["Dostarczanie wiadomości e-mail i spam"],"Encryption":["Szyfrowanie"],"Login and password":["Login i hasło"],"Merge aliases and accounts":["Scalanie aliasów i kont"],"Migrate to Proton":["Migracja do Proton"],"Notifications":["Powiadomienia"],"Other":["Inne"],"Plans and billing":["Plany i rozliczenia"],"Proton for Business":["Proton for Business"],"Sign up":["Rejestracja"],"Storage":["Przestrzeń dyskowa"],"Users, addresses, and identities":["Użytkownicy, adresy i tożsamości"]},"SupportForm:optionIntro":{"Select a topic":["Wybierz temat"]},"swiss_baseed_feature":{"Swiss based":["Ulokowany w Szwajcarii"]},"Testimonial":{"Awards":["Nagrody"],"Customers":["Klienci"],"Featured":["Wyróżnione"],"Go to testimonial source":["Przejdź do źródła referencji"],"Open source of award":["Otwórz źródło nagrody"],"Open source of quote":["Otwórz źródło cytatu"],"Reviews":["Opinie"],"Videos":["Pliki wideo"],"Watch on TikTok":["Oglądaj na TikTok"],"Watch on YouTube":["Oglądaj na YouTube"]},"TestimonialCategory":{"Awards":["Nagrody"],"Customers":["Klienci"],"Featured":["Wyróżnione"],"Media":["Multimedia"],"Reviews":["Opinie"],"Videos":["Pliki wideo"]},"Text":{"If you need help, check out our ${ supportLink }.":["Jeśli potrzebujesz pomocy, sprawdź naszą ${ supportLink }."],"The page you’re looking for might have been removed, or it could be an\nold link.":["Strona, której szukasz, mogła zostać usunięta lub link jest przestarzały."],"Your question may already have an answer in our knowledge base:":["Na Twoje pytanie może już istnieć odpowiedź w bazie wiedzy:"]},"Title":{"On this page":["Na tej stronie"],"Related articles":["Powiązane artykuły"],"Share ${ thisPage }":["Udostępnij ${ thisPage }"],"Switch to Proton Pass - Contact us":["Przejdź na Proton Pass – skontaktuj się z nami"],"Thank you!":["Dziękujemy!"],"this page":["tę stronę"]},"Tooltip":{"More information":["Więcej informacji"]},"tooltip_vpn":{"Access blocked content and browse privately. Includes ${ TOTAL_VPN_SERVERS }+ servers in ${ TOTAL_VPN_COUNTRIES }+ countries, highest VPN speed, ${ TOTAL_VPN_CONNECTIONS } VPN connections, worldwide streaming services, malware and ad-blocker, and more.":["Uzyskaj dostęp do zablokowanych treści i przeglądaj prywatnie Internet. Obejmuje ponad ${ TOTAL_VPN_SERVERS } serwerów w ponad ${ TOTAL_VPN_COUNTRIES } krajach, najwyższe prędkości VPN, ${ TOTAL_VPN_CONNECTIONS } połączeń VPN, usługi streamingu na całym świecie, blokowanie reklam oraz złośliwego oprogramowania i wiele więcej."]},"vpn_servers":{"Get Proton VPN Plus":["Wybierz plan Proton VPN Plus"]},"wallet_signup_2024:Action":{"Get Proton Wallet":["Wybierz Proton Wallet"]},"wallet_signup_2024:Homepage hero product link title":{"Wallet":["Portfel"]},"wallet_signup_2024:Homepage product navigation bar":{"Wallet":["Portfel"]},"wallet_signup_2024:menu item":{"Bitcoin guide":["Przewodnik po systemie Bitcoin"],"Proton Wallet news":["Aktualności Proton Wallet"],"Proton Wallet support":["Wsparcie dla Proton Wallet"]},"wallet_signup_2024:Pricing":{"Includes everything in Proton Unlimited and":["Zawiera wszystko, co Proton Unlimited oraz"],"Limited availability":["Ograniczona dostępność"],"The easiest way to securely own, send, and receive Bitcoin":["Najprostszy sposób na bezpieczne przechowywanie, wysyłanie i odbieranie waluty Bitcoin"]},"wallet_signup_2024:ProductRange":{"Discover Proton Wallet":["Odkryj rozwiązanie Proton Wallet"],"Store and transact Bitcoin privately with an encrypted self-custody wallet.":["Bezpiecznie przechowuj i przesyłaj Bitcoiny dzięki szyfrowanemu portfelowi typu self-custody."]},"wallet_signup_2024:wallet bitcoin":{"Learn about Bitcoin, the Internet's value network.":["Dowiedz się więcej o internetowym systemie gotówkowym Bitcoin."]},"wallet_signup_2024:wallet overview":{"Ensure you're always in control of your Bitcoin.":["Miej pełny nadzór nad swoimi Bitcoinami."]},"wallet_signup_2024:wallet security":{"The encrypted, open-source wallet that puts you in control.":["Szyfrowany portfel o otwartym kodzie źródłowym, który daje Ci pełną kontrolę."]}}},"base":"blog","cdn":{"enabledForAssets":true,"enabledForImages":true,"url":"https://pmecdn.protonweb.com/"},"unleashApi":"https://account.proton.me/api"};
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What is DKIM (DomainKeys Identified Mail)? | Proton
DKIM is an email authentication method that verifies that a message hasn’t been tampered with in transit. Learn how it works and why you need it to protect your email domain.
DKIM (DomainKeys Identified Mail) is an open standard for email authentication that cryptographically “signs” an email, helping verify that its sender’s address hasn’t been forged (spoofed) and its message hasn’t been tampered with in transit.
DKIM ensures that an email sent from your domain (for example, @yourdomain.com) is signed with an encryption key owned by your domain. This verifies that it came from a legitimate email server, not an attacker’s server that spoofed your domain.
What is DKIM used for?
DKIM is one of the main methods email servers use to authenticate emails. Together with SPF and DMARC, email platforms use DKIM to identify spoofed addresses, helping to sort and prevent spam and potential phishing emails.
If you send emails from your own domain (for example, yourname@yourdomain.com), you should use DKIM to help prevent attackers from spoofing it. If you don’t use DKIM, messages from your domain could be marked as spam or rejected by receiving mail servers.
What’s the difference between DKIM, SPF, and DMARC?
DKIM, SPF, and DMARC are email authentication methods that are used together to verify that emails are genuine. Here are the different roles they play:
DKIM (DomainKeys Identified Mail) cryptographically verifies that the sender’s address and email contents haven’t been changed in transit.
SPF (Sender Policy Framework) verifies that an email has been sent from an IP address authorized to send emails from the sender’s domain.
DMARC (Domain-based Message Authentication, Reporting, and Conformance) makes sure that the domain in DKIM and SPF checks matches the sender’s domain in the From field. It also specifies how email service providers should deliver a message that fails both DKIM and SPF: They can accept, reject, or mark it as spam.
The server sending the email uses its DKIM private key to “sign” the email. When the message arrives, the server receiving the mail verifies the signature using the corresponding DKIM public key.
Here’s what happens when you send an email with DKIM:
The sending mail server creates a hash of the email contents (the From field, subject, message body, etc.) and encrypts it using a private key that only trusted sending mail servers know.
When the email arrives, the receiving mail server looks up the corresponding public key in your domain’s DNS records and decrypts the hash in the DKIM signature.
The receiving mail server then generates its own hashes from the message body and the fields in the email and compares them with the decrypted hashes in the DKIM signature.
If the hashes match, this verifies that the email hasn’t been changed while being sent, and it passes DKIM.
In short, if an email passes DKIM, we learn that:
The message was sent from the domain in the DKIM signature
The message hasn’t been tampered with in transit
If a message fails DKIM, the email is treated as suspicious: The receiving server may send it to the recipient’s spam folder or reject it.
What is a DKIM signature?
A DKIM signature is a digital signature that’s added to an email header to allow the receiving server to verify cryptographically that the message hasn’t been tampered with.
A DKIM signature consists of a series of tags, like v=1, a=rsa-sha256, etc., as in this example:
Here’s what the main tags mean:
DKIM signature tag
Meaning
Required?
v=1
DKIM version number (should always be v=1)
Yes
a
Algorithm used to create the digital signature
Yes
d
Domain name (used with the DKIM selector to locate the public key)
Yes
s
DKIM selector (used to locate the public key — see below)
Yes
t
Signature time
No
x
Expiration time
No
bh
Hash of the message body
Yes
h
List of the header fields included in the signature (separated by colons)
Yes
b
The digital signature generated from bh and h and signed with the private key
Yes
What DKIM signature tags mean
When a sent email arrives, here’s how the DKIM signature is checked:
The receiving mail server uses the DKIM selector (s) and domain name (d) to locate and fetch the public key and decrypt the digital signature (b).
The server then creates its own hash from the message body and checks it matches the hash in the bh field. Then it creates a hash of the headers (including the DKIM signature containing the bh field) and compares that hash with the digital signature it decrypts using the public key.
If these hashes match, this verifies that the email hasn’t been altered and the message passes DKIM.
What is a DKIM record?
A DKIM record is where the DKIM public key is stored. The DKIM record is published and publicly available on a domain’s DNS server, so any receiving mail server can retrieve it to verify a DKIM signature.
By looking for a particular DKIM selector and domain name, a receiving email server can find the corresponding public key to check a DKIM signature.
What is a DKIM selector?
A DKIM selector is a unique name that indicates where the public key is stored in a domain’s DNS server. It’s stored together with your domain name in a DKIM record.
When you send an email with DKIM, the DKIM selector is included in the DKIM signature as an s= tag. In the example below, the DKIM selector is protonmail2
You can see the DKIM selector for your domain by emailing yourself and checking the DKIM signature in the email header.
Why use DKIM?
If you have your own domain name, we strongly recommend implementing DKIM, SPF, and DMARC. Here’s why:
Protect your domain
DKIM makes it hard for attackers to send emails pretending to be from your domain (email spoofing). Enabling DKIM will help to prevent bad actors from using your domain for spam or phishing attacks.
Improve email deliverability
Emails with a DKIM signature appear more legitimate and can be verified by a receiving mail server. So implementing DKIM for emails you send reduces the chances of them ending up in the spam folder.
Build your domain reputation
The more you send emails that pass DKIM and other authentication checks, the more you improve your domain’s sending reputation with internet service providers (ISPs) and email providers. So DKIM can help improve your emails’ deliverability over the long term.
Set up a single domain with Proton Mail Plus or get Proton Unlimited with support for three domains, 15 addresses, 500 GB of storage, and unlimited hide-my-email aliases.
Do you have an incident response plan to protect your business from financial
and reputational damage? Find out how Proton Pass for Business can help you stay
safe.