# Security

## Overview

[PBKDF2](https://en.wikipedia.org/wiki/PBKDF2) is used for key derivation and [AES-256-GCM](https://en.wikipedia.org/wiki/Galois/Counter_Mode) for encryption.

PBKDF2 uses a passphrase (Master Key) and salt value with a pseudorandom function to derive a cryptographic (secret) key for use by a cryptographic algorithm (AES-256-GCM) to encrypt data.

AES-256-GCM is used as a symmetric-key cipher, meaning the same key is used for encryption and decryption, avoiding the complexity of an asymmetric key where a public key is used for encryption and a private key is required for decryption.

A symmetric-key model was chosen for this library because the fetching, encryption, and decryption of secrets are a machine or application level operation, not a user specific one, thus ruling out the need for asymmetric keys.

The passphrase is provided via a `GITOPS_SECRETS_MASTER_KEY` environment variable. It should be a cryptographically random string unique to each environment and must be 16 characters or more.

You can generate a cryptographically random passphrase in your shell by running:

```sh
node -e 'process.stdout.write(require("crypto").randomBytes(16).toString("hex"))'
```

## Encryption and Decryption

The default 1,000,000 rounds of key-stretching should be more than sufficient, but can be configured via the `PBKDF2_ROUNDS` environment variable.

Note that the `PBKDF2_ROUNDS` environment variable is **not** needed at time of decryption as it is encoded into the final cipher text payload so it can be derived without risk of mismatched values which would prevent decryption.

## Providers

Providers are strongly encouraged to require auth related secrets to be supplied as environment variables to strongly discourage the hard-coding of credentials.

## Reporting a Vulnerability

Please report any vulnerabilities to [Doppler's Vulnerability Disclosure Program](https://doppler.com/vdp).