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Encryption key management

Strong data security and privacy rely on cryptographic algorithms, including encryption, hashing, and digital signatures. Cryptographic keys are essential to these algorithms, and the strength of protection depends on how well these keys are managed and safeguarded.

While cryptographic keys protect data, they are also just pieces of data themselves, subject to the same cyber threats as any other data.

If an encryption key is compromised (leaked or guessed), the entire protection mechanism collapses. All the data that uses the compromised key is now unprotected. This includes data encrypted before the key was compromised and the data that will be encrypted after the compromise, unless the key is changed.

The effectiveness of a cryptographic solution thus relies on the strength, secrecy, and proper handling of its keys. Storing a cryptographic key with or near the data it protects, or using it carelessly, can render it ineffective in providing real data protection. Secure key storage mechanism

Best practices include using different cryptographic keys for various purposes, generating strong random keys, avoiding reuse, and regularly performing key rotation. Collectively, these practices are referred to as “key management”, which is the secret sauce of a strong data security strategy.

Managing encryption keys on the backend

Handling encryption keys on the backend server is challenging and often overlooked until a real cyberattack occurs, by which point, it’s too late.

When encryption keys are needed in different parts of a system to decrypt data, they create points of vulnerability. If any component is compromised, the exposed key can jeopardize all protected data.

The best approach is to use different keys for different purposes. This way, even if one key is compromised, the damage is limited.

Here are some key management principles to have in mind:

  1. Key rotation policy. Regularly rotate encryption keys, such as annually or after a security incident. Managing multiple encryption keys requires a systematic approach.
  2. KMS: a shield against exportation. Key management systems (KMS) are designed to restrict the exportation of encryption keys, ensuring they are used solely for authorized internal operations.
  3. DEK storage risks. Storing data encryption keys (DEKs) alongside the data they encrypt is a bad gamble. Mitigate this risk by using layered encryption: secure DEKs with a key encryption key (KEK) managed by a KMS.
  4. Diagnostics come at a price. Debugging an encrypted system can be tricky. Sharing encryption keys on platforms like Slack exposes the keys, and re-encrypting the data is harder! Instead, create temporary access for specific users, and revoke it as soon as it’s no longer needed.