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_SERVERS }+ servers in ${ TOTAL_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 ${ TOTAL_SERVERS } servidores em +${ TOTAL_COUNTRIES } países, conecte até 10 dispositivos, acesse serviços de streaming do mundo todo, malware e bloqueador de anúncios 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":{"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"]},"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 ${ issues[0] }."],"We are experiencing issues with one or more services at the moment.":["No momento, estamos com problemas em um ou mais serviços."]},"suggestions":{"Suggestions":["Sugestões"]},"Support":{"Sub category":["Subcategoria","Subcategorias"]},"Support article":{"${ 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 categories":{"Browse Proton product support":["Navegar pelo suporte a produtos da Proton"]},"Support category":{"There is no article in this category yet.":["Ainda não há nenhum artigo nesta categoria."]},"Support troubleshooting":{"--- Select ---":["--- Selecionar ---"],"App version":["Versão do aplicativo"],"Browser":["Navegador"],"Check if this helps":["Confira se isso ajuda"],"Choose a category for your question":["Escolha uma categoria para sua pergunta"],"Choose a product":["Selecione um produto"],"Did this solve your issue ?":["Isso resolveu seu problema?"],"Faster assistance is just a few clicks away — please make your selections":["Assistência mais rápida está a apenas alguns cliques de distância — faça suas seleções"],"No, contact support":["Não, entrar em contato com o suporte"],"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"],"Troubleshooting":["Solução de problemas"],"What can we help with ?":["Como podemos ajudar você?"],"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":{"Find the plan that's right for you":["Encontre o plano certo para você"],"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_calendar":{"Create up to 20 custom & shareable encrypted calendars. On top of that, add up to 5 calendars from friends, family, colleagues, and organizations.":["Crie até 20 calendários compartilháveis personalizados e criptografados. Além disso, é possível adicional até 5 calendários de amigos, família, colegas e organizações."]},"tooltip_vpn":{"Access blocked content and browse privately. Includes ${ TOTAL_SERVERS }+ servers in ${ TOTAL_COUNTRIES }+ countries, highest VPN speed, ${ TOTAL_VPN_CONNECTIONS } VPN connections, worldwide streaming services, malware and ad-blocker, and more.":["Acesse conteúdo bloqueado e navegue com privacidade. Inclui mais de ${ TOTAL_SERVERS } servidores em mais de +${ TOTAL_COUNTRIES } países, VPN com a mais alta velocidade, ${ TOTAL_VPN_CONNECTIONS } conexões VPN, serviços de streaming no mundo todo, malware e bloqueador de anúncios e muito mais."],"Access blocked content and browse privately. Includes ${ TOTAL_SERVERS }+ servers in ${ TOTAL_COUNTRIES }+ countries, highest VPN speed, 10 VPN connections, worldwide streaming services, malware and ad-blocker, and more.":["Acesse conteúdo bloqueado e navegue com privacidade. Inclui mais de ${ TOTAL_SERVERS } servidores em mais de +${ TOTAL_COUNTRIES } países, VPN com a mais alta velocidade, 10 conexões VPN, serviços de streaming no mundo todo, malware e bloqueador de anúncios e muito mais."]},"version_history_label":{"Version history":["Histórico de versões"]},"version_history_tooltip":{"Store up to ${ versionHistoryNumber } versions of each file for up to ${ years } years":["Armazene até ${ versionHistoryNumber } versões de cada arquivo por até ${ years } anos"]},"vpn_features_link":{"View VPN plans":["Visualizar planos de VPN"]},"vpn_features_useCase":{"Access blocked content and browse privately":["Acesse conteúdo bloqueado e navegue com privacidade"]}}},"unleashApi":"https://account.proton.me/api"};
// We need to import data (the framework context) from the server
// This Astro feature with define:vars works well but creates an inline script
// So we can't directly import the initFramework helper, we have to store the context
window.frameworkContext = frameworkContext;
})();
Proton Mail Bridge is a desktop application that runs in the background on your computer and encrypts and decrypts your mail as it enters and leaves your device. It allows for full integration of your Proton Mail account with email clients like Microsoft Outlook, Mozilla Thunderbird, and Apple Mail.
This document discusses how Bridge handles sensitive information, describes its potential attack vectors, and explains the security features that mitigate these attacks. (Note: This security model applies to the Bridge application for Linux, macOS, and Windows.)
This security model is technical in nature, but was written in plain language so that the average user can understand the important takeaways. You can also read more about what Proton Mail is and is not designed to protect you from in the Proton Mail threat model(new window).
As part of normal, day-to-day operations, Bridge must handle different types of data with varying levels of sensitivity. This data includes (but is not limited to):
User credentials and an access token for authentication with the Proton servers
Public and private keys for sending and reading messages
Encrypted messages, attachments, and metadata
We explain how Bridge secures this sensitive data in greater detail below.
Your passwords never leave your machine Users log in to Bridge, which in turn authenticates with the Proton Mail API using the Secure Remote Password protocol(new window). This authentication process ensures a user’s password never leaves their machine, and it generates an access token and a refresh token.
The access token is relatively short-lived and is used to authenticate any subsequent API requests; it is stored in the device’s memory. The refresh token is used to generate new access tokens and is stored securely in the operating system’s keychain (Windows Credentials Manager, macOS Keychain, or pass/gnome-keyring on Linux). The user’s hashed and salted mailbox password (used to decrypt their PGP keys) and Bridge password (used to connect an email client to Bridge) are also held in the operating system’s keychain.
Ensuring a secure connection to Proton servers Bridge communicates with the Proton Mail API over an encrypted TLS connection. It additionally employs TLS certificate public key pinning to ensure it only connects to trusted Proton Mail servers. If Bridge receives an untrusted public key, it will assume an unknown intermediary is pretending to be a Proton server and immediately warn the user.
Bridge never stores or shares a user’s PGP keys After the user logs in, Bridge downloads their encrypted, private PGP keys from the Proton servers and unlocks them. These keys are held in the device’s memory, never on disk. Whenever a user turns off their device, they wipe its memory. This makes it unlikely an attacker will be able to obtain a copy of a user’s PGP keys, even if they steal the user’s device. These keys are also never shared with other applications on your device and stay within Bridge’s memory space.
Bridge does not store decrypted message data When an IMAP client requests a message body or attachment, it is downloaded from the Proton servers as an encrypted PGP message, decrypted locally, and then transmitted to the IMAP client. Similar to the user’s PGP keys, Bridge does not permanently store any message bodies or attachments to disk, further reducing the amount of sensitive data available on the device.
Attack mitigation
Here we describe the potential attack vectors of Bridge and how we mitigate these attacks.
Reducing the threat of a MITM attack
As described, Bridge employs TLS certificate pinning, which mitigates the risk of a network-level man-in-the-middle (MITM) attack.
Furthermore, the content of messages sent from Bridge to Proton Mail users or external recipients using PGP has an additional layer of protection thanks to end-to-end encryption. This means Bridge encrypts the user’s message before it leaves their device. The message remains encrypted until it reaches the recipient’s device, which decrypts it. This prevents any third party, including Proton Mail, from accessing the content of a user’s message. Messages sent this way remain inaccessible because a user’s mailbox password never leaves their device and, thus, is never transmitted to an attacker.
Secure updates
Bridge on Windows and macOS includes a feature that allows it to self-update. The update process has additional safeguards in place to verify that only trusted versions of Bridge that are created and signed by Proton Mail are installed.
Bridge recommended use cases
Bridge is a unique tool when compared to the other Proton Mail apps. As such, there are specific cases in which it would be more practical and useful than other Proton Mail apps.
Below are some examples of recommended use cases for Bridge:
Offline editing If you find yourself without a stable Internet connection, you can use your favorite email client with Bridge to download emails while you do have good Internet access and then process them offline later. Most email clients will automatically send and receive your drafts once you are back online.
Offline backups of your emails are required If you need to have offline copies of your messages for whatever reason, Bridge is the easiest way to accomplish this. The Bridge app enables your IMAP/SMTP client to do this automatically if you choose to do so.
Add Proton Mail security to already known email clients If you or your staff do not feel confident learning how to use a new email service, Bridge lets you add Proton Mail encryption to your messages while continuing to use your favorite IMAP/SMTP email client. These clients include Outlook, Thunderbird, and Apple Mail, all applications that many people are familiar with. This means that once you set up Bridge, using it does not require any new training.
Bridge security model scope
No application is 100% secure, and no piece of software can protect its user against every potential threat. Proton Mail Bridge is engineered to provide additional protection to its users’ data, but certain conditions are outside of the scope of the security model.
User device security We assume users run the Bridge app in a safe environment. For instance, we assume that Bridge program files are installed to a location where normal (non-admin) users have no write privileges. Furthermore, we expect the user’s device to be free of any malicious software (keyloggers, screen recorders, memory scanners, etc.) that could access the device’s data in memory or on disk. Bridge, unfortunately, cannot secure your data if your device is already compromised.
Additionally, we assume that the IMAP/SMTP ports that the email client connects to are not exposed beyond the device that Bridge is running on. The Bridge application ignores all connections that do not originate from the localhost, and we assume the user will not attempt to circumvent this.
Bridge installer security We assume that the user securely downloaded the Bridge installer from our server (the server should present a valid and expected SSL certificate). For Windows and macOS, the operating system inspects the signatures on the installer file automatically before installation. It then displays the results to the user, which we assume they properly verify. We recommend Linux users refer to our support article on Verifying the Proton Mail Bridge package(new window) for instructions. If you download the Bridge application from an unauthorized source, we cannot guarantee the safety of the installer.
Our recommendations for keeping your device secure
We have invested heavily in the security of our Bridge app. You can help maximize the security of your own device by taking a few simple measures:
Encrypt your device’s hard drive. Windows(new window) and macOS(new window) devices all have built-in encryption systems, but you have to turn them on. Once you have encrypted your drive, write down your recovery code and store it in a secure place.
Enable your operating system’s antivirus protection, if available.
Ensure your network ports are secured by a firewall to prevent outside machines from connecting to them.
Do not install untrusted programs on your device. This includes unknown open source versions of Bridge. Downloading Bridge directly from Proton Mail(new window) is the safest option.
Do not open links or download attachments from untrusted senders.
Conclusion
Our first priority is always our users’ security. Our goal is to make it easy for anyone to protect their privacy by creating tools that apply advanced cryptography to their messages automatically. The Bridge tool was designed to add additional security to already existing IMAP/SMTP email clients. By keeping your device secure, you can use these email clients and still take charge of your data. Thank you for your support!
Proton Mail and Proton VPN are funded by community contributions. If you would like to support our development efforts, you can upgrade to a paid plan(new window). Thank you for your support.
Secure, seamless communication is the foundation of every business. As more
organizations secure their data with Proton, we’ve dramatically expanded our
ecosystem with new products and services, from our password manager to Dark Web
Monitoring for cr
On the subject of cybersecurity, one term that often comes up is brute force
attack. A brute force attack is any attack that doesn’t rely on finesse, but
instead uses raw computing power to crack security or even the underlying
encryption.
In this a
Section 702 of the Foreign Intelligence Surveillance Act has become notorious as
the legal justification allowing federal agencies like the NSA, CIA, and FBI to
perform warrantless wiretaps, which sweep up the data of hundreds of thousands
of US citi
In response to the growing number of data breaches, Proton Mail offers a feature
to paid subscribers called Dark Web Monitoring. Our system checks if your
credentials or other data have been leaked to illegal marketplaces and alerts
you if so. Often
Your email address is your online identity, and you share it whenever you create
a new account for an online service. While this offers convenience, it also
leaves your identity exposed if hackers manage to breach the services you use.
Data breaches
Our mission at Proton is to help usher in an internet that protects your privacy
by default, secures your data, and gives you the freedom of choice.
Today we’re taking another step in this direction with the launch of our open
source password manage