minio/pkg/kms/kms.go

112 lines
3.3 KiB
Go

// MinIO Cloud Storage, (C) 2021 MinIO, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package kms
import (
"encoding"
"encoding/json"
)
// 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
if err := json.Unmarshal(text, &v); err != nil {
return err
}
d.KeyID, d.Plaintext, d.Ciphertext = v.KeyID, nil, v.Ciphertext
return nil
}