90 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			90 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
// Package box is an asymmetric implementation of config/secrets using nacl/box
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package box
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import (
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	"github.com/micro/go-micro/v2/config/secrets"
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	"github.com/pkg/errors"
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	naclbox "golang.org/x/crypto/nacl/box"
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	"crypto/rand"
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)
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const keyLength = 32
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type box struct {
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	options secrets.Options
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	publicKey  [keyLength]byte
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	privateKey [keyLength]byte
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}
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// NewSecrets returns a nacl-box codec
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func NewSecrets(opts ...secrets.Option) secrets.Secrets {
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	b := &box{}
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	for _, o := range opts {
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		o(&b.options)
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	}
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	return b
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}
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// Init initialises a box
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func (b *box) Init(opts ...secrets.Option) error {
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	for _, o := range opts {
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		o(&b.options)
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	}
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	if len(b.options.PrivateKey) != keyLength || len(b.options.PublicKey) != keyLength {
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		return errors.Errorf("a public key and a private key of length %d must both be provided", keyLength)
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	}
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	copy(b.privateKey[:], b.options.PrivateKey)
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	copy(b.publicKey[:], b.options.PublicKey)
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	return nil
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}
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// Options returns options
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func (b *box) Options() secrets.Options {
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	return b.options
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}
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// String returns nacl-box
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func (*box) String() string {
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	return "nacl-box"
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}
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// Encrypt encrypts a message with the sender's private key and the receipient's public key
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func (b *box) Encrypt(in []byte, opts ...secrets.EncryptOption) ([]byte, error) {
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	var options secrets.EncryptOptions
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	for _, o := range opts {
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		o(&options)
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	}
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	if len(options.RecipientPublicKey) != keyLength {
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		return []byte{}, errors.New("recepient's public key must be provided")
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	}
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	var recipientPublicKey [keyLength]byte
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	copy(recipientPublicKey[:], options.RecipientPublicKey)
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	var nonce [24]byte
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	if _, err := rand.Reader.Read(nonce[:]); err != nil {
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		return []byte{}, errors.Wrap(err, "couldn't obtain a random nonce from crypto/rand")
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	}
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	return naclbox.Seal(nonce[:], in, &nonce, &recipientPublicKey, &b.privateKey), nil
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}
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// Decrypt Decrypts a message with the receiver's private key and the sender's public key
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func (b *box) Decrypt(in []byte, opts ...secrets.DecryptOption) ([]byte, error) {
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	var options secrets.DecryptOptions
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	for _, o := range opts {
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		o(&options)
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	}
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	if len(options.SenderPublicKey) != keyLength {
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		return []byte{}, errors.New("sender's public key bust be provided")
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	}
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	var nonce [24]byte
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	var senderPublicKey [32]byte
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	copy(nonce[:], in[:24])
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	copy(senderPublicKey[:], options.SenderPublicKey)
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	decrypted, ok := naclbox.Open(nil, in[24:], &nonce, &senderPublicKey, &b.privateKey)
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	if !ok {
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		return []byte{}, errors.New("incoming message couldn't be verified / decrypted")
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	}
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	return decrypted, nil
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}
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