About Postum.App

Postum.App is the app for managing your digital legacy. You can securely store data for selected contacts. If you die or become unable to use your data yourself for any other reason, your contacts will automatically be granted access to the data.

Frequently asked Questions

Have you asked yourself what happens to your online accounts when you die, for example? Who has access to your social media accounts after your death? Who has access to your e-mail account? Who has access to your online banking? The answer to these questions is the Postum.App. With Postum.App you manage your digital legacy such as credentials.

Postum.App cannot replace an analogous will. The formal requirements for a will are regulated for Germany in ยง 2247 BGB. Other countries may have different regulations. Postum.App can only be used to store a digital copy of the will. In addition, the location of the original will should be stored in Postum.App.

We, the operators of Postum.App, never get to see your data in plain text. Before your data is stored on our servers, it is encrypted on your device. The encrypted data is transferred to our server. The data can be decrypted only with your personal Postum.App password. Your contacts have their own passwords with which they can decrypt the data released to them. The decryption of the data is also done only on your/their devices.

To operate Postum.App, we need to store your email address and your contacts' email addresses in plain text so that we can send you status messages. You can freely choose the names of your contacts, there is no need to provide the real names. For example, you can use pseudonyms like "Honey" and "Sugar". The names are also stored in plain text.

Your legacy data is encrypted on your device before being stored on our servers.

Postum.App uses strong state-of-the-art encryption. We use the Web Crypto API in your browser for all cryptographic operations.

When you register, Postum.App creates an RSA key pair for you consisting of a private and a public key. To enable you to use Postum.App from anywhere, we store the key pair on our servers. Your private key is encrypted with AES 256 bit before it is transferred to our server. For encryption, a secure key is derived from your personal password using PBKDF2.

Your legacy data is encrypted using AES 256 bit with a randomly generated key. The generated key is encrypted with your personal public key and stored on our servers together with your encrypted legacy data.

Since your password is used for the cryptographic operations, it must not be transmitted to our servers in clear text, as it is common for normal user authentication. That is why we derive an authentication password from your personal password using PBKDF2. This authentication password is transmitted to our server during login and compared with the authentication password we have stored. Bcrypt is used as the hash algorithm for the authentication password.

Postum.App requires a regular sign of life from you. The sign of life is, for example, when you log in to Postum.App or click a "heartbeat" link from Postum.App. If your signs of life are missing for a longer period of time, your contacts will get access to the legacy. A notification will be sent to your email address when a contact accesses the legacy. If the access was allowed by mistake, you have the possibility to change the legacy data, e.g. to protect the connected online accounts again.