mirror of
https://github.com/edgelesssys/constellation.git
synced 2024-12-11 17:04:22 -05:00
887dcda78b
Encrypt each object with a random DEK and attach the encrypted DEK as object metadata. Encrpt the DEK with a key from the keyservice. All objects use the same KEK until a keyrotation takes place.
74 lines
2.0 KiB
Go
74 lines
2.0 KiB
Go
/*
|
|
Copyright (c) Edgeless Systems GmbH
|
|
|
|
SPDX-License-Identifier: AGPL-3.0-only
|
|
*/
|
|
|
|
/*
|
|
Package crypto provides encryption and decryption functions for the s3proxy.
|
|
It uses AES-256-GCM to encrypt and decrypt data.
|
|
*/
|
|
package crypto
|
|
|
|
import (
|
|
"fmt"
|
|
|
|
aeadsubtle "github.com/tink-crypto/tink-go/v2/aead/subtle"
|
|
kwpsubtle "github.com/tink-crypto/tink-go/v2/kwp/subtle"
|
|
"github.com/tink-crypto/tink-go/v2/subtle/random"
|
|
)
|
|
|
|
// Encrypt generates a random key to encrypt a plaintext using AES-256-GCM.
|
|
// The generated key is encrypted using the supplied key encryption key (KEK).
|
|
// The ciphertext and encrypted data encryption key (DEK) are returned.
|
|
func Encrypt(plaintext []byte, kek [32]byte) (ciphertext []byte, encryptedDEK []byte, err error) {
|
|
dek := random.GetRandomBytes(32)
|
|
aesgcm, err := aeadsubtle.NewAESGCMSIV(dek)
|
|
if err != nil {
|
|
return nil, nil, fmt.Errorf("getting aesgcm: %w", err)
|
|
}
|
|
|
|
ciphertext, err = aesgcm.Encrypt(plaintext, []byte(""))
|
|
if err != nil {
|
|
return nil, nil, fmt.Errorf("encrypting plaintext: %w", err)
|
|
}
|
|
|
|
keywrapper, err := kwpsubtle.NewKWP(kek[:])
|
|
if err != nil {
|
|
return nil, nil, fmt.Errorf("getting kwp: %w", err)
|
|
}
|
|
|
|
encryptedDEK, err = keywrapper.Wrap(dek)
|
|
if err != nil {
|
|
return nil, nil, fmt.Errorf("wrapping dek: %w", err)
|
|
}
|
|
|
|
return ciphertext, encryptedDEK, nil
|
|
}
|
|
|
|
// Decrypt decrypts a ciphertext using AES-256-GCM.
|
|
// The encrypted DEK is decrypted using the supplied KEK.
|
|
func Decrypt(ciphertext, encryptedDEK []byte, kek [32]byte) ([]byte, error) {
|
|
keywrapper, err := kwpsubtle.NewKWP(kek[:])
|
|
if err != nil {
|
|
return nil, fmt.Errorf("getting kwp: %w", err)
|
|
}
|
|
|
|
dek, err := keywrapper.Unwrap(encryptedDEK)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("unwrapping dek: %w", err)
|
|
}
|
|
|
|
aesgcm, err := aeadsubtle.NewAESGCMSIV(dek)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("getting aesgcm: %w", err)
|
|
}
|
|
|
|
plaintext, err := aesgcm.Decrypt(ciphertext, []byte(""))
|
|
if err != nil {
|
|
return nil, fmt.Errorf("decrypting ciphertext: %w", err)
|
|
}
|
|
|
|
return plaintext, nil
|
|
}
|