44a05be1af
Add database field level encryption level to sensitive data to reduce the risk in term of data leak. I dedice to have only one key for now in a near future I may move to one master key and one encryption key per organization to make rotation easiest. I don't use built-in pg_crypto function to have clear seperation and avoid any encryption key leak. Signed-off-by: Bryan Frimin <bryan@getprobo.com>
117 lines
2.8 KiB
Go
117 lines
2.8 KiB
Go
// Copyright (c) 2025 Probo Inc <hello@getprobo.com>.
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice appear in all copies.
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//
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// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
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// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
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// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
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// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
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// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
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// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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// PERFORMANCE OF THIS SOFTWARE.
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package cipher
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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"encoding/base64"
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"encoding/json"
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"fmt"
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"io"
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)
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type (
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EncryptionKey [32]byte
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)
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func NewEncryptionKey(key string) (EncryptionKey, error) {
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if len(key) != 32 {
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return EncryptionKey{}, fmt.Errorf("key must be 32 bytes for AES-256")
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}
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var encryptionKey EncryptionKey
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copy(encryptionKey[:], key)
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return encryptionKey, nil
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}
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func (k EncryptionKey) Bytes() []byte {
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return k[:]
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}
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func (k *EncryptionKey) UnmarshalJSON(data []byte) error {
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var key string
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if err := json.Unmarshal(data, &key); err != nil {
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return err
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}
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return k.UnmarshalText([]byte(key))
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}
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func (k *EncryptionKey) UnmarshalText(text []byte) error {
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decoded, err := base64.StdEncoding.DecodeString(string(text))
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if err != nil {
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return fmt.Errorf("cannot decode base64 key: %w", err)
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}
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if len(decoded) != 32 {
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return fmt.Errorf("key must be 32 bytes for AES-256, got %d bytes after base64 decoding", len(decoded))
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}
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copy(k[:], decoded)
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return nil
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}
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func (k EncryptionKey) MarshalJSON() ([]byte, error) {
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return json.Marshal(base64.StdEncoding.EncodeToString(k[:]))
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}
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func Encrypt(data []byte, key EncryptionKey) ([]byte, error) {
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block, err := aes.NewCipher(key.Bytes())
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if err != nil {
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return nil, err
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}
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nonce := make([]byte, 12)
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if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
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return nil, err
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}
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aesgcm, err := cipher.NewGCM(block)
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if err != nil {
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return nil, err
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}
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ciphertext := aesgcm.Seal(nonce, nonce, data, nil)
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return ciphertext, nil
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}
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func Decrypt(data []byte, key EncryptionKey) ([]byte, error) {
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block, err := aes.NewCipher(key.Bytes())
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if err != nil {
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return nil, err
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}
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aesgcm, err := cipher.NewGCM(block)
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if err != nil {
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return nil, err
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}
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if len(data) < 12 {
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return nil, fmt.Errorf("ciphertext too short")
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}
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nonce, ciphertext := data[:12], data[12:]
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plaintext, err := aesgcm.Open(nil, nonce, ciphertext, nil)
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if err != nil {
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return nil, fmt.Errorf("cannot decrypt: %w", err)
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}
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return plaintext, nil
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}
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