all-in-one privacy solution":["O Proton Unlimited é uma solução única de privacidade"],"Black Friday":["Black Friday"],"No ads. Privacy by default.":["Sem anúncios. Privacidade por padrão."],"People before profits":["Pessoas acima do lucro"],"Security through transparency":["Segurança por meio da transparência"],"The best Proton Mail ${ BLACK_FRIDAY } deals":["As melhores ofertas de ${ BLACK_FRIDAY } do Proton Mail"],"The world’s only community- supported email service":["O único serviço de e-mail do mundo apoiado pela comunidade"]},"specialoffer:limited":{"${ hours } hour":["${ hours } hora","${ hours } horas"],"${ hoursLeft }, ${ minutesLeft } and ${ secondsLeft } left":["${ hoursLeft }, ${ minutesLeft }, e ${ secondsLeft } restantes"],"${ minutes } minute":["${ minutes } minuto","${ minutes } minutos"],"${ seconds } second":["${ seconds } segundo","${ seconds } segundos"],"Limited time offer":["Oferta por tempo limitado"]},"specialoffer:listitem":{"Create multiple addresses":["Crie vários endereços"],"Hide-my-email aliases":["Use aliases do hide-my-email"],"Quickly unsubscribe from newsletters":["Cancele a assinatura de newsletters rapidamente"],"Use your own domain name":["Use seu próprio nome de domínio"]},"specialoffer:logos":{"As featured in":["Destaques"]},"specialoffer:metadescription":{"Get an encrypted email that protects your privacy":["Obtenha um e-mail criptografado que proteja sua privacidade"]},"specialoffer:metatitle":{"Proton Mail Black Friday Sale - Up to 40% off":["Oferta de Black Friday do Proton Mail - Até 40% de desconto"]},"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.":["Obtenha até 40% de desconto nas assinaturas do Proton Mail nesta Black Friday. Confira ótimas ofertas em nossos planos de e-mail seguro com criptografia de ponta a ponta."]},"specialoffer:newmetatitle":{"Proton Mail Black Friday sale | Up to 40% off secure email":["Oferta de Black Friday do Proton Mail - Até 40% de desconto no e-mail protegido"]},"specialoffer:note":{"* Billed at ${ TOTAL_SUM } for the first year":["* Com o preço de ${ TOTAL_SUM } no primeiro ano"],"*Billed at ${ TOTAL_SUM } for the first 2 years":["*Com o preço de ${ TOTAL_SUM } nos primeiros dois anos"],"30-day money-back guarantee":["Garantia de reembolso de 30 dias"],"Billed at ${ TOTAL_SUM } for the first 2 years":["Com o preço de ${ TOTAL_SUM } nos primeiros dois anos"],"Billed at ${ TOTAL_SUM } for the first year":["Com o preço de ${ TOTAL_SUM } no primeiro ano"],"You save ${ SAVE_SUM }":["Economize ${ SAVE_SUM }"]},"specialoffer:off":{"${ DISCOUNT } off":["-${ DISCOUNT }"],"${ PERCENT_OFF } off":["-${ PERCENT_OFF }"]},"specialoffer:testimonial":{"I love my ProtonMail":["Adoro ProtonMail"],"My favorite email service":["Meu serviço favorito de e-mail"],"Thanks Proton for keeping us all safe in the complicated internet universe.":["Agradecemos ao Proton por nos manter a salvo no complicado universo da internet."],"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":["Você recebe pelo que paga. No caso das grandes tecnologias, você se acostuma quando não paga nada. Parei de usar o Gmail e troquei para o @ProtonMail"]},"specialoffer:time":{"Days":["Dias"],"Hours":["Horas"],"Min":["Min"]},"specialoffer:title":{"And much more":["E muito mais"],"Make your inbox yours":["Deixe a caixa de entrada do seu jeito"],"Safe from trackers":["A salvo de rastreadores"],"Stay organized":["Mantenha-se organizado"],"Black Friday email deals":["Ofertas de e-mail da Black Friday"],"Don’t just take our word for it":["Não confie apenas em nossa palavra"],"Our story":["Nossa história"],"Transfer your data from Google in one click":["Transfira seus dados do Google com um clique"]},"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.":["Acesse conteúdo bloqueado e navegue com privacidade. Inclui mais de ${ TOTAL_VPN_SERVERS } servidores em mais de ${ TOTAL_VPN_COUNTRIES } países, conexão com até 10 dispositivos, acesso a serviços de streaming do mundo todo, um bloqueador de anúncios e malware e muito mais."],"Easily share your calendar with your family, friends or colleagues, and view external calendars.":["Compartilhe facilmente seus calendários com amigos, familiares ou colegas e visualize calendários externos."],"Includes support for 1 custom email domain, 10 email addresses, 10 hide-my-email aliases, calendar sharing, and more.":["Inclui suporte para 1 domínio de e-mail personalizado, 10 endereços de e-mail, 10 aliases do hide-my-email, compartilhamento de calendário e muito mais."],"Includes support for 3 custom email domains, 15 email addresses, unlimited hide-my-email aliases, calendar sharing, and more.":["Inclui suporte para 3 domínios de e-mail personalizados, 15 endereços de e-mail, aliases ilimitados do hide-my-email, compartilhamento de calendário e muito mais."],"Manage up to 25 calendars, mobile apps, secured with end-to-end encryption, 1-click calendar import from Google, and more.":["Gerencie até 25 calendários, apps para dispositivos móveis, protegidos com criptografia de ponta a ponta, importação de calendário com 1 clique do Google e muito mais."]},"Status banner":{"Learn more":["Saiba mais"],"Please note that at the moment we are experiencing issues with the ${ issues[0] } service.":["No momento, estamos com problemas no serviço ${ issues[0] }."],"We are experiencing issues with one or more services at the moment.":["No momento, estamos com problemas em um ou mais serviços."]},"Status Banner":{"At the moment we are experiencing issues with the Proton VPN service":["No momento estamos enfrentando problemas com o serviço Proton VPN"],"Learn more":["Saiba mais"]},"suggestions":{"Suggestions":["Sugestões"]},"Support":{"Sub category":["Subcategoria","Subcategorias"]},"Support article":{"${ readingTime } min":["${ readingTime } min","${ readingTime } min"],"Category":["Categoria","Categorias"],"Didn’t find what you were looking for?":["Não encontrou o que procura?"],"General contact":["Contato geral"],"Get help":["Obter ajuda"],"Legal contact":["Contato jurídico"],"Media contact":["Contato de mídia"],"Partnerships contact":["Contato de parcerias"],"Reading":["Leitura"]},"Support troubleshooting":{"App version":["Versão do aplicativo"],"Browser":["Navegador"],"Check if this helps":["Confira se isso ajuda"],"Choose a product":["Selecione um produto"],"Did this solve your issue?":["Isso resolveu seu problema?"],"Faster assistance is just a few clicks away":["Assistência mais rápida a apenas alguns cliques de distância"],"How can we help?":["Como podemos ajudar?"],"No, contact support":["Não, entrar em contato com o suporte"],"Please fill out one field after another":["Preencha os campos em sequência"],"Please make your selections":["Faça suas seleções"],"Proton account":["Conta Proton"],"Proton Bridge":["Proton Bridge"],"Proton Calendar":["Proton Calendar"],"Proton Drive":["Proton Drive"],"Proton for Business":["Proton for Business"],"Proton Mail":["Proton Mail"],"Proton Pass":["Proton Pass"],"Proton VPN":["Proton VPN"],"Thank you for your feedback":["Agradecemos pelo feedback"],"What can we help with?":["Com o que podemos ajudar?"],"Yes":["Sim"]},"support_modal_search_query":{"Search query":["Consulta de pesquisa"]},"support_search_button":{"Search":["Pesquisar"]},"support_search_i_am_looking_for":{"I'm looking for":["Estou procurando"]},"SupportForm":{"For a faster resolution, please report the issue from the Bridge app: Help > Report a problem.":["Para uma resolução mais rápida, informe o problema no aplicativo Bridge: Ajuda > Comunicar um problema."],"Information":["Informações"]},"SupportForm:option":{"Account Security":["Segurança da conta"],"Contacts":["Contatos"],"Custom email domain":["Domínio de e-mail personalizado"],"Email delivery and Spam":["Entrega de e-mail e spam"],"Encryption":["Criptografia"],"Login and password":["Início de sessão e senha"],"Merge aliases and accounts":["Combinar alias e contas"],"Migrate to Proton":["Migrar para a Proton"],"Notifications":["Notificações"],"Other":["Outros"],"Plans and billing":["Planos e faturamento"],"Proton for Business":["Proton for Business"],"Sign up":["Criar conta"],"Storage":["Armazenamento"],"Users, addresses, and identities":["Usuários, endereços e identidades"]},"SupportForm:optionIntro":{"Select a topic":["Selecione um tópico"]},"swiss_baseed_feature":{"Swiss based":["Sediado na Suíça"]},"Testimonial":{"Awards":["Prêmios"],"Customers":["Clientes"],"Featured":["Em destaque"],"Go to testimonial source":["Ir para a página inicial de depoimentos"],"Reviews":["Avaliações"],"Videos":["Vídeos"]},"Text":{"If you need help, check out our ${ supportLink }.":["Se precisar de ajuda, confira nossa ${ supportLink }."],"The page you’re looking for might have been removed, or it could be an\nold link.":["É possível que a página que você está procurando tenha sido removida ou seja um\nlink antigo."]},"Title":{"On this page":["Nesta página"],"Related articles":["Artigos relacionados"],"Share ${ thisPage }":["Compartilhar ${ thisPage }"],"Thank you!":["Obrigado!"],"this page":["esta página"]},"Tooltip":{"More information":["Mais informações"]},"tooltip_vpn":{"Access blocked content and browse privately. 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Effective Spam Filtering with Encrypted Email | Proton
As many of you have noticed, in recent weeks, spam filtering performance at Proton Mail has dramatically improved. This is because we have recently deployed a series of updates to improve spam filtering performance. In this three part series of posts, we will discuss many of the spam challenges
Proton Mail faces and discuss in detail how to fight spam in the end-to-end encrypted world. Proton Mail’s spam challenges can be summarized broadly into three categories.
Incoming Spam
Outgoing Spam
Internal Spam
Incoming spam is spam sent to Proton Mail from third party email providers, for example Hotmail. Outgoing spam is spammers using Proton Mail to send spam to third party email providers. Finally, Internal spam is Proton Mail accounts being used to spam other Proton Mail accounts. Each of these pose very different risks and challenges. As an encrypted email service provider with over 1 million users, spam is a continuous battle and one of the toughest challenges to overcome.
In this blog post, we will be discussing incoming spam filtering. In future blog posts, we will cover the challenges of preventing Proton Mail from being used by spammers and the challenges of doing spam filtering with end-to-end encrypted emails which we cannot read.
Incoming Spam
Incoming spam is not dangerous, but it can be a major inconvenience for users. Incoming spam doesn’t just clog up user inboxes, but it can also cause a performance problem if not handled efficiently due to the sheer volume of incoming spam emails which sometimes arrives at the Proton Mail servers.
Emails that come from third party email providers obviously cannot be delivered with end-to-end encryption, but upon reaching our mail servers, we will encrypt them with the recipient’s public key before saving the messages(new window). All this is done in memory so that by the time anything is permanently stored to disk, the email is already un-readable to us. This gives us a very limited window to perform spam filtering on incoming messages.
When an incoming message is received, it goes through the following filtering steps. The goal is to use less computationally extensive methods first to reject as much spam as possible before more expensive methods are used.
1. First, the IP address of the incoming SMTP server is checked against spam blacklists which contain IP addresses of servers we have previously received spam from. If we receive a hit, the message is rejected.
2. Secondly, the message is passed through our customized Bayesian filters which marks suspicious messages as spam.
3. Next, we generate checksums of incoming messages and check them against a database of known spam messages. If there is a match, we mark the message as spam. The checksums are done in such a way that it is also effective against mutating spam emails.
4. Afterwards, we also apply a few other anti-spam techniques which we cannot detail here for security reasons (see below)
5. Since email headers can be easily spoofed and abused, we also verify the authenticity (SPF, DKIM, and DMARC) of incoming emails to protect users. An email that fails DMARC(new window) is likely spoofed so it will be sent to the spam folder with a warning for our users.
Over the past few months, we have optimized and improved many of the above components to achieve a 500% improvement in spam detection. In doing this, we learned a few lessons:
Security through Obscurity
Generally speaking, security through obscurity is not recommended. This is why Proton Mail is open source(new window), and we have all of our front end code open to inspection from the community(new window). Security through obscurity is the anti-thesis of open source, and relies on the notion that security of a system can be improved if attackers do not know how the system works. Generally, this is a bad approach. It is better to have a system so secure that even if attackers know how it works, they cannot bypass it. This is certainly the case with the PGP email encryption that Proton Mail utilizes.
However, one case where security through obscurity DOES work is fighting spammers. This is particularly the case when it comes to fighting outgoing spam. Fighting spam is like trying to hit a moving target, it requires constant adjustment and tuning, especially since the distinction between spam and non-spam messages can be unclear at times.
There simply isn’t any foolproof method for defeating spam. Thus, if spammers don’t know how we are blocking their messages, it makes it much more difficult for them to find a workaround. This is why we cannot publish detailed specs of how our spam filters work. It also means we cannot open source our backend server configs which contain our spam filter settings.
In terms of privacy and trust, there is little advantage in open sourcing the server configs because even if the configs were released, there is no way to guarantee that is the config running on the server side. On the other hand, releasing the backend configs would let spammers know exactly what they need to do to bypass our spam filters, which would put the entire Proton Mail community at risk.
Personalized Spam Filtering
Before designing our spam filtering system, we looked through months of spam reports from the community. What we quickly learned is that every user has a different definition of spam. What you consider to be spam won’t be the same as what your neighbor considers to be spam. Thus, it is impossible to define a single ruleset that works for everybody. This pushed us in the direction of personalized rulesets.
Today, every single Proton Mail account comes with its own spam filter settings which are unique to that account. When you mark messages as spam or not-spam, the filter will dynamically adjust to take into account your personal preferences. You can also view and modify your personal spam filter settings(new window). Proton Mail also accounts for whether an email came from one of your contacts or not. If it comes from a contact, it is allowed through the spam filter.
The Best Spam Filter is You
Proton Mail has a comprehensive multi-tiered protection system to prevent spam from entering your inbox, but actually you are the best protection against spam. The vast majority of spam can be avoided by simply not giving your Proton Mail email address to unscrupulous websites which then resell that information to spammers. To learn more about how to avoid receiving spam in the first place, read our guide to avoiding spam.
Billions of people use online document editors like Google Docs or Microsoft 365
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there is a growing concern about Big Tech platforms having access to your
content, tracki
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Proton prioritizes our community’s privacy and data security in every aspect of
our business.
To further demonstrate our commitment, we underwent a rigorous external audit
and – on May 2, 2024 – received our ISO 27001 certification.
As an organiz
Anyone with an iPhone can now enjoy Proton Drive’s secure and private photo
backup capabilities. This feature is gradually rolling out to the Proton
community and will be available to everyone by the end of this week.
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organization. This was probably evident from the way in which we got started via
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launch development. As