enveloppekryptering

Enveloppekryptering, also known as envelope encryption or content encryption key (CEK) encryption, is a method for encrypting data where a separate, randomly generated key is used to encrypt the actual data. This data encryption key (DEK) is then itself encrypted using a master key, often referred to as a key encryption key (KEK). The encrypted DEK is typically stored alongside the encrypted data.

This approach offers several advantages. Firstly, it allows for efficient encryption of large amounts of data. Instead of encrypting the entire dataset with a single, potentially complex master key, only the smaller DEK needs to be encrypted by the master key. The DEK is then used to encrypt the bulk data using a fast symmetric encryption algorithm.

Secondly, it simplifies key management. The master key, which is used to encrypt all the DEKs, can be stored and managed more securely, for example, in a hardware security module (HSM) or a dedicated key management service. This means the master key is less frequently accessed, reducing its exposure to potential compromise.

When decryption is required, the process is reversed. The encrypted DEK is first decrypted using the master key. Once the DEK is retrieved, it can then be used to decrypt the actual data. This two-tiered encryption strategy is widely used in cloud storage services, databases, and other applications where data security and efficient handling of large datasets are crucial.