VOL-2017 voltha-lib moved from voltha-go;
release version 2.2.1

Based on voltha-go commit 5259f8e52b3e3f5c7ad422a4b0e506e1d07f6b36

Change-Id: I8bbecdf456e420714a4016120eafc0d237c80565
diff --git a/vendor/gopkg.in/jcmturner/gokrb5.v7/crypto/rfc8009/encryption.go b/vendor/gopkg.in/jcmturner/gokrb5.v7/crypto/rfc8009/encryption.go
new file mode 100644
index 0000000..86aae09
--- /dev/null
+++ b/vendor/gopkg.in/jcmturner/gokrb5.v7/crypto/rfc8009/encryption.go
@@ -0,0 +1,128 @@
+// Package rfc8009 provides encryption and checksum methods as specified in RFC 8009
+package rfc8009
+
+import (
+	"crypto/aes"
+	"crypto/hmac"
+	"crypto/rand"
+	"errors"
+	"fmt"
+
+	"gopkg.in/jcmturner/aescts.v1"
+	"gopkg.in/jcmturner/gokrb5.v7/crypto/common"
+	"gopkg.in/jcmturner/gokrb5.v7/crypto/etype"
+	"gopkg.in/jcmturner/gokrb5.v7/iana/etypeID"
+)
+
+// EncryptData encrypts the data provided using methods specific to the etype provided as defined in RFC 8009.
+func EncryptData(key, data []byte, e etype.EType) ([]byte, []byte, error) {
+	kl := e.GetKeyByteSize()
+	if e.GetETypeID() == etypeID.AES256_CTS_HMAC_SHA384_192 {
+		kl = 32
+	}
+	if len(key) != kl {
+		return []byte{}, []byte{}, fmt.Errorf("incorrect keysize: expected: %v actual: %v", e.GetKeyByteSize(), len(key))
+	}
+	ivz := make([]byte, aes.BlockSize)
+	return aescts.Encrypt(key, ivz, data)
+}
+
+// EncryptMessage encrypts the message provided using the methods specific to the etype provided as defined in RFC 8009.
+// The encrypted data is concatenated with its integrity hash to create an encrypted message.
+func EncryptMessage(key, message []byte, usage uint32, e etype.EType) ([]byte, []byte, error) {
+	kl := e.GetKeyByteSize()
+	if e.GetETypeID() == etypeID.AES256_CTS_HMAC_SHA384_192 {
+		kl = 32
+	}
+	if len(key) != kl {
+		return []byte{}, []byte{}, fmt.Errorf("incorrect keysize: expected: %v actual: %v", kl, len(key))
+	}
+	if len(key) != e.GetKeyByteSize() {
+	}
+	//confounder
+	c := make([]byte, e.GetConfounderByteSize())
+	_, err := rand.Read(c)
+	if err != nil {
+		return []byte{}, []byte{}, fmt.Errorf("could not generate random confounder: %v", err)
+	}
+	plainBytes := append(c, message...)
+
+	// Derive key for encryption from usage
+	var k []byte
+	if usage != 0 {
+		k, err = e.DeriveKey(key, common.GetUsageKe(usage))
+		if err != nil {
+			return []byte{}, []byte{}, fmt.Errorf("error deriving key for encryption: %v", err)
+		}
+	}
+
+	// Encrypt the data
+	iv, b, err := e.EncryptData(k, plainBytes)
+	if err != nil {
+		return iv, b, fmt.Errorf("error encrypting data: %v", err)
+	}
+
+	ivz := make([]byte, e.GetConfounderByteSize())
+	ih, err := GetIntegityHash(ivz, b, key, usage, e)
+	if err != nil {
+		return iv, b, fmt.Errorf("error encrypting data: %v", err)
+	}
+	b = append(b, ih...)
+	return iv, b, nil
+}
+
+// DecryptData decrypts the data provided using the methods specific to the etype provided as defined in RFC 8009.
+func DecryptData(key, data []byte, e etype.EType) ([]byte, error) {
+	kl := e.GetKeyByteSize()
+	if e.GetETypeID() == etypeID.AES256_CTS_HMAC_SHA384_192 {
+		kl = 32
+	}
+	if len(key) != kl {
+		return []byte{}, fmt.Errorf("incorrect keysize: expected: %v actual: %v", kl, len(key))
+	}
+	ivz := make([]byte, aes.BlockSize)
+	return aescts.Decrypt(key, ivz, data)
+}
+
+// DecryptMessage decrypts the message provided using the methods specific to the etype provided as defined in RFC 8009.
+// The integrity of the message is also verified.
+func DecryptMessage(key, ciphertext []byte, usage uint32, e etype.EType) ([]byte, error) {
+	//Derive the key
+	k, err := e.DeriveKey(key, common.GetUsageKe(usage))
+	if err != nil {
+		return nil, fmt.Errorf("error deriving key: %v", err)
+	}
+	// Strip off the checksum from the end
+	b, err := e.DecryptData(k, ciphertext[:len(ciphertext)-e.GetHMACBitLength()/8])
+	if err != nil {
+		return nil, err
+	}
+	//Verify checksum
+	if !e.VerifyIntegrity(key, ciphertext, b, usage) {
+		return nil, errors.New("integrity verification failed")
+	}
+	//Remove the confounder bytes
+	return b[e.GetConfounderByteSize():], nil
+}
+
+// GetIntegityHash returns a keyed integrity hash of the bytes provided as defined in RFC 8009
+func GetIntegityHash(iv, c, key []byte, usage uint32, e etype.EType) ([]byte, error) {
+	// Generate and append integrity hash
+	// The HMAC is calculated over the cipher state concatenated with the
+	// AES output, instead of being calculated over the confounder and
+	// plaintext.  This allows the message receiver to verify the
+	// integrity of the message before decrypting the message.
+	// H = HMAC(Ki, IV | C)
+	ib := append(iv, c...)
+	return common.GetIntegrityHash(ib, key, usage, e)
+}
+
+// VerifyIntegrity verifies the integrity of cipertext bytes ct.
+func VerifyIntegrity(key, ct []byte, usage uint32, etype etype.EType) bool {
+	h := make([]byte, etype.GetHMACBitLength()/8)
+	copy(h, ct[len(ct)-etype.GetHMACBitLength()/8:])
+	ivz := make([]byte, etype.GetConfounderByteSize())
+	ib := append(ivz, ct[:len(ct)-(etype.GetHMACBitLength()/8)]...)
+	expectedMAC, _ := common.GetIntegrityHash(ib, key, usage, etype)
+	return hmac.Equal(h, expectedMAC)
+}