Function deriveAESKey

internal/crypto/aes.go:20–27

deriveAESKey derives a 32-byte AES key from the provided input keying material using HKDF-SHA256 with a fixed info string and no salt.

(ikm string)

// deriveAESKey derives a 32-byte AES key from the provided input keying
// material using HKDF-SHA256 with a fixed info string and no salt.
func deriveAESKey(ikm string) ([]byte, error) {
	reader := hkdf.New(sha256.New, []byte(ikm), nil, []byte(hkdfInfo))
	key := make([]byte, 32)
	if _, err := io.ReadFull(reader, key); err != nil {
		return nil, err
	}
	return key, nil
}

// EncryptAES encrypts plaintext using AES-256-GCM. The nonce is prepended to
// the ciphertext and the result is encoded as base64 RawURL.