Ejemplo n.º 1
0
func (alg *AesGcm) Encrypt(aad, plainText, cek []byte) (iv, cipherText, authTag []byte, err error) {

	cekSizeBits := len(cek) << 3

	if cekSizeBits != alg.keySizeBits {
		return nil, nil, nil, errors.New(fmt.Sprintf("AesGcm.Encrypt(): expected key of size %v bits, but was given %v bits.", alg.keySizeBits, cekSizeBits))
	}

	if iv, err = arrays.Random(12); err != nil {
		return nil, nil, nil, err
	}

	var block cipher.Block

	if block, err = aes.NewCipher(cek); err != nil {
		return nil, nil, nil, err
	}

	var aesgcm cipher.AEAD

	if aesgcm, err = cipher.NewGCM(block); err != nil {
		return nil, nil, nil, err
	}

	cipherWithTag := aesgcm.Seal(nil, iv, plainText, aad)

	cipherText = cipherWithTag[:len(cipherWithTag)-aesgcm.Overhead()]
	authTag = cipherWithTag[len(cipherWithTag)-aesgcm.Overhead():]

	return iv, cipherText, authTag, nil
}
Ejemplo n.º 2
0
// encrypt is used to encrypt a value
func (b *AESGCMBarrier) encrypt(path string, term uint32, gcm cipher.AEAD, plain []byte) []byte {
	// Allocate the output buffer with room for tern, version byte,
	// nonce, GCM tag and the plaintext
	capacity := termSize + 1 + gcm.NonceSize() + gcm.Overhead() + len(plain)
	size := termSize + 1 + gcm.NonceSize()
	out := make([]byte, size, capacity)

	// Set the key term
	binary.BigEndian.PutUint32(out[:4], term)

	// Set the version byte
	out[4] = b.currentAESGCMVersionByte

	// Generate a random nonce
	nonce := out[5 : 5+gcm.NonceSize()]
	rand.Read(nonce)

	// Seal the output
	switch b.currentAESGCMVersionByte {
	case AESGCMVersion1:
		out = gcm.Seal(out, nonce, plain, nil)
	case AESGCMVersion2:
		out = gcm.Seal(out, nonce, plain, []byte(path))
	default:
		panic("Unknown AESGCM version")
	}

	return out
}
Ejemplo n.º 3
0
func (alg *AesGcmKW) WrapNewKey(cekSizeBits int, key interface{}, header map[string]interface{}) (cek []byte, encryptedCek []byte, err error) {
	if kek, ok := key.([]byte); ok {

		kekSizeBits := len(kek) << 3

		if kekSizeBits != alg.keySizeBits {
			return nil, nil, errors.New(fmt.Sprintf("AesGcmKW.WrapNewKey(): expected key of size %v bits, but was given %v bits.", alg.keySizeBits, kekSizeBits))
		}

		if cek, err = arrays.Random(cekSizeBits >> 3); err != nil {
			return nil, nil, err
		}

		var iv []byte

		if iv, err = arrays.Random(12); err != nil {
			return nil, nil, err
		}

		var block cipher.Block

		if block, err = aes.NewCipher(kek); err != nil {
			return nil, nil, err
		}

		var aesgcm cipher.AEAD

		if aesgcm, err = cipher.NewGCM(block); err != nil {
			return nil, nil, err
		}

		cipherWithTag := aesgcm.Seal(nil, iv, cek, nil)

		cipherText := cipherWithTag[:len(cipherWithTag)-aesgcm.Overhead()]
		authTag := cipherWithTag[len(cipherWithTag)-aesgcm.Overhead():]

		header["iv"] = base64url.Encode(iv)
		header["tag"] = base64url.Encode(authTag)

		return cek, cipherText, nil
	}

	return nil, nil, errors.New("AesGcmKW.WrapNewKey(): expected key to be '[]byte' array")
}
Ejemplo n.º 4
0
// encrypt is used to encrypt a value
func (b *AESGCMBarrier) encrypt(term uint32, gcm cipher.AEAD, plain []byte) []byte {
	// Allocate the output buffer with room for tern, version byte,
	// nonce, GCM tag and the plaintext
	capacity := termSize + 1 + gcm.NonceSize() + gcm.Overhead() + len(plain)
	size := termSize + 1 + gcm.NonceSize()
	out := make([]byte, size, capacity)

	// Set the key term
	binary.BigEndian.PutUint32(out[:4], term)

	// Set the version byte
	out[4] = aesgcmVersionByte

	// Generate a random nonce
	nonce := out[5 : 5+gcm.NonceSize()]
	rand.Read(nonce)

	// Seal the output
	out = gcm.Seal(out, nonce, plain, nil)
	return out
}
Ejemplo n.º 5
0
// encrypt is used to encrypt a value
func (b *AESGCMBarrier) encrypt(gcm cipher.AEAD, plain []byte) []byte {
	// Allocate the output buffer with room for epoch, version byte,
	// nonce, GCM tag and the plaintext
	capacity := epochSize + 1 + gcm.NonceSize() + gcm.Overhead() + len(plain)
	size := epochSize + 1 + gcm.NonceSize()
	out := make([]byte, size, capacity)

	// Set the epoch to 1
	out[3] = keyEpoch

	// Set the version byte
	out[4] = aesgcmVersionByte

	// Generate a random nonce
	nonce := out[5 : 5+gcm.NonceSize()]
	rand.Read(nonce)

	// Seal the output
	out = gcm.Seal(out, nonce, plain, nil)
	return out
}