Comment le chiffrement de bout en bout ouvre la voie à la connaissance zéro - Livre blanc

Le fondement d'une architecture sécurisée commence par le chiffrement, en particulier le chiffrement de bout en bout. Chez Bitwarden, nous cryptons vos données sensibles dès que vous les saisissez dans un client Bitwarden. Avant d'être stockées sur votre appareil, les données sont cryptées. Il n'existe pas de données non cryptées dans le coffre-fort, sauf lorsque vous en avez le contrôle et que vous consultez les informations dans un client Bitwarden où vous avez saisi votre adresse électronique et votre mot de passe principal.

À partir de là, toutes les données du coffre-fort restent cryptées lorsqu'elles sont envoyées au nuage Bitwarden ou à un serveur Bitwarden auto-hébergé. Lors de la synchronisation des données avec d'autres clients, celles-ci restent cryptées jusqu'à ce que l'adresse électronique unique et le mot de passe principal soient à nouveau saisis.

Cela signifie que Bitwarden, en tant que société, ne peut pas voir vos mots de passe, ils restent cryptés de bout en bout avec votre email individuel et votre mot de passe principal. Nous ne conservons jamais votre mot de passe principal et nous n'y avons pas accès.

Pour les données de la chambre forte, Bitwarden utilise le cryptage AES 256 bits, une norme industrielle considérée comme incassable. Pour votre mot de passe principal, PBKDF2 SHA-256 est utilisé pour dériver la clé qui crypte vos données du coffre-fort. Pour en savoir plus sur la sécurité de Bitwarden, veuillez consulter notre FAQ sur la sécurité.

Bien entendu, le détail important du chiffrement de bout en bout est la clé de déchiffrement. Tant que l'utilisateur final est le seul à en avoir connaissance, une solution peut évoluer vers une architecture à zéro connaissance.

Dans certains cas, les fournisseurs de logiciels et de services encouragent le cryptage mais conservent la clé. De notre point de vue, ces cas ne sont pas considérés comme des cas d'ignorance puisque les fournisseurs de logiciels et de services ont techniquement la capacité de décrypter les données.

When users have control of the encryption key, they control access to the data, and can provide encrypted data to a password manager without the password management company having access to, or knowledge of, that data.

This is the fundamental premise on which well-designed password managers work. They facilitate strong and unique passwords that only you can access. Doing so requires zero knowledge of the secret data, and therefore users must control the encryption key. We refer to this as zero knowledge encryption.

But there is information beyond the secret Vault data that might be shared with a software or service provider. For example, an email address might serve as a unique customer identifier. One could claim that this isn’t zero knowledge, and that would be correct.

At a minimum, zero knowledge must pertain to secret data. In the case of a password manager, that means all information within the password Vault. At the same time, it is important to recognize the realities of software, services, and users, and that in order for a commercial relationship to exist, their likely needs to be some knowledge exchanged between parties.

In the world of password managers, that line can get blurry. For example there are some password managers (not Bitwarden) that retain unencrypted URLs and websites for which you store passwords. While they claim that this benefits users, ultimately it provides these companies with detailed information on which websites users visit, when they do so, and every log in.

Bitwarden takes a more conservative view of what constitutes sensitive data, and therefore encrypts all of the information in your Vault, including the websites you visit, even the names of your individual items and folders. We use the term zero knowledge encryption because only you retain the keys to your Vault, and the entirety of your vault is encrypted. Bitwarden cannot see your passwords, your websites, or anything else that you put in your Vault. Bitwarden also does not know your Master Password. So take good care of it, because if it gets lost, the Bitwarden team cannot recover it for you.

The zero trust model initially emerged as a way for organizations to get beyond the traditional thinking of internal and external threats to their IT operations. Today, companies need to protect from threats coming from both inside and outside. Zero Trust models often use technologies like identity and access management, encryption, multi-factor authentication, and permissions to operate.

Of course, between password managers and users adopting software or services, there is likely going to be at least some element of trust between the two parties. The password management provider trusts that the user will not violate the terms of service, and the user trusts that the password management provider will live up to their stated offering. However, everyone is better off if the boundaries of required trust are limited, so that even the possibility of sensitive data being compromised is eliminated altogether, hence the zero trust model.

While we stand by to support our customers with a trusted relationship, we can reduce the reliance on implied trust through the Bitwarden self-hosted offering. This deployment enables businesses with greater flexibility and control over their infrastructure. Running your own Bitwarden instance could be on an airgap network, further reducing risks by being disconnected from the internet.

At Bitwarden we take this trusted relationship with our users seriously. We also built our solution to be safe and secure with end-to-end encryption for all Vault data, including website URLs, so that your sensitive data is “zero trust” secure.