github.com/grailbio/base@v0.0.11/crypto/encryption/registry.go (about)

     1  // Copyright 2017 GRAIL, Inc. All rights reserved.
     2  // Use of this source code is governed by the Apache-2.0
     3  // license that can be found in the LICENSE file.
     4  
     5  package encryption
     6  
     7  import (
     8  	"crypto/cipher"
     9  	"fmt"
    10  	"hash"
    11  	"sync"
    12  )
    13  
    14  type db struct {
    15  	sync.Mutex
    16  	registries map[string]KeyRegistry
    17  }
    18  
    19  var registries = &db{registries: map[string]KeyRegistry{}}
    20  
    21  // KeyRegistry represents a database of keys for a particular cipher, ie.
    22  // implementations of KeyRegistry manage the keys for a particular cipher.
    23  // AEAD is supported by wrapping the block ciphers provided.
    24  type KeyRegistry interface {
    25  	GenerateKey() (ID []byte, err error)
    26  	BlockSize() int
    27  	HMACSize() int
    28  	NewBlock(ID []byte, opts ...interface{}) (hmac hash.Hash, block cipher.Block, err error)
    29  	NewGCM(block cipher.Block, opts ...interface{}) (aead cipher.AEAD, err error)
    30  }
    31  
    32  // Lookup returns the key registry, if any, named by the supplied name.
    33  func Lookup(name string) (KeyRegistry, error) {
    34  	registries.Lock()
    35  	defer registries.Unlock()
    36  	r := registries.registries[name]
    37  	if r == nil {
    38  		return nil, fmt.Errorf("no such registry: %v", name)
    39  	}
    40  	return r, nil
    41  }
    42  
    43  // Register registers a new KeyRegistry using the supplied name.
    44  func Register(name string, registry KeyRegistry) error {
    45  	registries.Lock()
    46  	defer registries.Unlock()
    47  	if _, present := registries.registries[name]; present {
    48  		return fmt.Errorf("already registered: %v", registry)
    49  	}
    50  	registries.registries[name] = registry
    51  	return nil
    52  }