blob: db3a149ad795d0508e4f29bb601a890460d443b5 [file] [log] [blame]
package crypto
import (
//RFC: 3961 Section 6.3
des3-cbc-hmac-sha1-kd, hmac-sha1-des3-kd
protocol key format 24 bytes, parity in low
bit of each
key-generation seed 21 bytes
hash function SHA-1
HMAC output size 160 bits
message block size 8 bytes
default string-to-key empty string
encryption and triple-DES encrypt and
decryption functions decrypt, in outer-CBC
mode (cipher block size
8 octets)
key generation functions:
random-to-key DES3random-to-key (see
string-to-key DES3string-to-key (see
The des3-cbc-hmac-sha1-kd encryption type is assigned the value
sixteen (16). The hmac-sha1-des3-kd checksum algorithm is assigned a
checksum type number of twelve (12)*/
// Des3CbcSha1Kd implements Kerberos encryption type des3-cbc-hmac-sha1-kd
type Des3CbcSha1Kd struct {
// GetETypeID returns the EType ID number.
func (e Des3CbcSha1Kd) GetETypeID() int32 {
return etypeID.DES3_CBC_SHA1_KD
// GetHashID returns the checksum type ID number.
func (e Des3CbcSha1Kd) GetHashID() int32 {
return chksumtype.HMAC_SHA1_DES3_KD
// GetKeyByteSize returns the number of bytes for key of this etype.
func (e Des3CbcSha1Kd) GetKeyByteSize() int {
return 24
// GetKeySeedBitLength returns the number of bits for the seed for key generation.
func (e Des3CbcSha1Kd) GetKeySeedBitLength() int {
return 21 * 8
// GetHashFunc returns the hash function for this etype.
func (e Des3CbcSha1Kd) GetHashFunc() func() hash.Hash {
return sha1.New
// GetMessageBlockByteSize returns the block size for the etype's messages.
func (e Des3CbcSha1Kd) GetMessageBlockByteSize() int {
//For traditional CBC mode with padding, it would be the underlying cipher's block size
return des.BlockSize
// GetDefaultStringToKeyParams returns the default key derivation parameters in string form.
func (e Des3CbcSha1Kd) GetDefaultStringToKeyParams() string {
var s string
return s
// GetConfounderByteSize returns the byte count for confounder to be used during cryptographic operations.
func (e Des3CbcSha1Kd) GetConfounderByteSize() int {
return des.BlockSize
// GetHMACBitLength returns the bit count size of the integrity hash.
func (e Des3CbcSha1Kd) GetHMACBitLength() int {
return e.GetHashFunc()().Size() * 8
// GetCypherBlockBitLength returns the bit count size of the cypher block.
func (e Des3CbcSha1Kd) GetCypherBlockBitLength() int {
return des.BlockSize * 8
// StringToKey returns a key derived from the string provided.
func (e Des3CbcSha1Kd) StringToKey(secret string, salt string, s2kparams string) ([]byte, error) {
if s2kparams != "" {
return []byte{}, errors.New("s2kparams must be an empty string")
return rfc3961.DES3StringToKey(secret, salt, e)
// RandomToKey returns a key from the bytes provided.
func (e Des3CbcSha1Kd) RandomToKey(b []byte) []byte {
return rfc3961.DES3RandomToKey(b)
// DeriveRandom generates data needed for key generation.
func (e Des3CbcSha1Kd) DeriveRandom(protocolKey, usage []byte) ([]byte, error) {
r, err := rfc3961.DeriveRandom(protocolKey, usage, e)
return r, err
// DeriveKey derives a key from the protocol key based on the usage value.
func (e Des3CbcSha1Kd) DeriveKey(protocolKey, usage []byte) ([]byte, error) {
r, err := e.DeriveRandom(protocolKey, usage)
if err != nil {
return nil, err
return e.RandomToKey(r), nil
// EncryptData encrypts the data provided.
func (e Des3CbcSha1Kd) EncryptData(key, data []byte) ([]byte, []byte, error) {
return rfc3961.DES3EncryptData(key, data, e)
// EncryptMessage encrypts the message provided and concatenates it with the integrity hash to create an encrypted message.
func (e Des3CbcSha1Kd) EncryptMessage(key, message []byte, usage uint32) ([]byte, []byte, error) {
return rfc3961.DES3EncryptMessage(key, message, usage, e)
// DecryptData decrypts the data provided.
func (e Des3CbcSha1Kd) DecryptData(key, data []byte) ([]byte, error) {
return rfc3961.DES3DecryptData(key, data, e)
// DecryptMessage decrypts the message provided and verifies the integrity of the message.
func (e Des3CbcSha1Kd) DecryptMessage(key, ciphertext []byte, usage uint32) ([]byte, error) {
return rfc3961.DES3DecryptMessage(key, ciphertext, usage, e)
// VerifyIntegrity checks the integrity of the plaintext message.
func (e Des3CbcSha1Kd) VerifyIntegrity(protocolKey, ct, pt []byte, usage uint32) bool {
return rfc3961.VerifyIntegrity(protocolKey, ct, pt, usage, e)
// GetChecksumHash returns a keyed checksum hash of the bytes provided.
func (e Des3CbcSha1Kd) GetChecksumHash(protocolKey, data []byte, usage uint32) ([]byte, error) {
return common.GetHash(data, protocolKey, common.GetUsageKc(usage), e)
// VerifyChecksum compares the checksum of the message bytes is the same as the checksum provided.
func (e Des3CbcSha1Kd) VerifyChecksum(protocolKey, data, chksum []byte, usage uint32) bool {
c, err := e.GetChecksumHash(protocolKey, data, usage)
if err != nil {
return false
return hmac.Equal(chksum, c)