minio/internal/kms/kms.go

118 lines
3.5 KiB
Go

// Copyright (c) 2015-2021 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package kms
import (
"encoding"
"encoding/json"
jsoniter "github.com/json-iterator/go"
)
// KMS is the generic interface that abstracts over
// different KMS implementations.
type KMS interface {
// Stat returns the current KMS status.
Stat() (Status, error)
// CreateKey creates a new key at the KMS with the given key ID.
CreateKey(keyID string) error
// GenerateKey generates a new data encryption key using the
// key referenced by the key ID.
//
// The KMS may use a default key if the key ID is empty.
// GenerateKey returns an error if the referenced key does
// not exist.
//
// The context is associated and tied to the generated DEK.
// The same context must be provided when the generated key
// should be decrypted. Therefore, it is the callers
// responsibility to remember the corresponding context for
// a particular DEK. The context may be nil.
GenerateKey(keyID string, context Context) (DEK, error)
// DecryptKey decrypts the ciphertext with the key referenced
// by the key ID. The context must match the context value
// used to generate the ciphertext.
DecryptKey(keyID string, ciphertext []byte, context Context) ([]byte, error)
}
// Status describes the current state of a KMS.
type Status struct {
Name string // The name of the KMS
Endpoints []string // A set of the KMS endpoints
// DefaultKey is the key used when no explicit key ID
// is specified. It is empty if the KMS does not support
// a default key.
DefaultKey string
}
// DEK is a data encryption key. It consists of a
// plaintext-ciphertext pair and the ID of the key
// used to generate the ciphertext.
//
// The plaintext can be used for cryptographic
// operations - like encrypting some data. The
// ciphertext is the encrypted version of the
// plaintext data and can be stored on untrusted
// storage.
type DEK struct {
KeyID string
Plaintext []byte
Ciphertext []byte
}
var (
_ encoding.TextMarshaler = (*DEK)(nil)
_ encoding.TextUnmarshaler = (*DEK)(nil)
)
// MarshalText encodes the DEK's key ID and ciphertext
// as JSON.
func (d DEK) MarshalText() ([]byte, error) {
type JSON struct {
KeyID string `json:"keyid"`
Ciphertext []byte `json:"ciphertext"`
}
return json.Marshal(JSON{
KeyID: d.KeyID,
Ciphertext: d.Ciphertext,
})
}
// UnmarshalText tries to decode text as JSON representation
// of a DEK and sets DEK's key ID and ciphertext to the
// decoded values.
//
// It sets DEK's plaintext to nil.
func (d *DEK) UnmarshalText(text []byte) error {
type JSON struct {
KeyID string `json:"keyid"`
Ciphertext []byte `json:"ciphertext"`
}
var v JSON
var json = jsoniter.ConfigCompatibleWithStandardLibrary
if err := json.Unmarshal(text, &v); err != nil {
return err
}
d.KeyID, d.Plaintext, d.Ciphertext = v.KeyID, nil, v.Ciphertext
return nil
}