blob: 6e650eb6c19dd866a071ea8a531624d29b54db30 [file] [log] [blame]
David K. Bainbridgebd6b2882021-08-26 13:31:02 +00001package crypto
2
3import (
4 "crypto/des"
5 "crypto/hmac"
6 "crypto/sha1"
7 "errors"
8 "hash"
9
10 "github.com/jcmturner/gokrb5/v8/crypto/common"
11 "github.com/jcmturner/gokrb5/v8/crypto/rfc3961"
12 "github.com/jcmturner/gokrb5/v8/iana/chksumtype"
13 "github.com/jcmturner/gokrb5/v8/iana/etypeID"
14)
15
16//RFC: 3961 Section 6.3
17
18// Des3CbcSha1Kd implements Kerberos encryption type des3-cbc-hmac-sha1-kd
19type Des3CbcSha1Kd struct {
20}
21
22// GetETypeID returns the EType ID number.
23func (e Des3CbcSha1Kd) GetETypeID() int32 {
24 return etypeID.DES3_CBC_SHA1_KD
25}
26
27// GetHashID returns the checksum type ID number.
28func (e Des3CbcSha1Kd) GetHashID() int32 {
29 return chksumtype.HMAC_SHA1_DES3_KD
30}
31
32// GetKeyByteSize returns the number of bytes for key of this etype.
33func (e Des3CbcSha1Kd) GetKeyByteSize() int {
34 return 24
35}
36
37// GetKeySeedBitLength returns the number of bits for the seed for key generation.
38func (e Des3CbcSha1Kd) GetKeySeedBitLength() int {
39 return 21 * 8
40}
41
42// GetHashFunc returns the hash function for this etype.
43func (e Des3CbcSha1Kd) GetHashFunc() func() hash.Hash {
44 return sha1.New
45}
46
47// GetMessageBlockByteSize returns the block size for the etype's messages.
48func (e Des3CbcSha1Kd) GetMessageBlockByteSize() int {
49 //For traditional CBC mode with padding, it would be the underlying cipher's block size
50 return des.BlockSize
51}
52
53// GetDefaultStringToKeyParams returns the default key derivation parameters in string form.
54func (e Des3CbcSha1Kd) GetDefaultStringToKeyParams() string {
55 var s string
56 return s
57}
58
59// GetConfounderByteSize returns the byte count for confounder to be used during cryptographic operations.
60func (e Des3CbcSha1Kd) GetConfounderByteSize() int {
61 return des.BlockSize
62}
63
64// GetHMACBitLength returns the bit count size of the integrity hash.
65func (e Des3CbcSha1Kd) GetHMACBitLength() int {
66 return e.GetHashFunc()().Size() * 8
67}
68
69// GetCypherBlockBitLength returns the bit count size of the cypher block.
70func (e Des3CbcSha1Kd) GetCypherBlockBitLength() int {
71 return des.BlockSize * 8
72}
73
74// StringToKey returns a key derived from the string provided.
75func (e Des3CbcSha1Kd) StringToKey(secret string, salt string, s2kparams string) ([]byte, error) {
76 if s2kparams != "" {
77 return []byte{}, errors.New("s2kparams must be an empty string")
78 }
79 return rfc3961.DES3StringToKey(secret, salt, e)
80}
81
82// RandomToKey returns a key from the bytes provided.
83func (e Des3CbcSha1Kd) RandomToKey(b []byte) []byte {
84 return rfc3961.DES3RandomToKey(b)
85}
86
87// DeriveRandom generates data needed for key generation.
88func (e Des3CbcSha1Kd) DeriveRandom(protocolKey, usage []byte) ([]byte, error) {
89 r, err := rfc3961.DeriveRandom(protocolKey, usage, e)
90 return r, err
91}
92
93// DeriveKey derives a key from the protocol key based on the usage value.
94func (e Des3CbcSha1Kd) DeriveKey(protocolKey, usage []byte) ([]byte, error) {
95 r, err := e.DeriveRandom(protocolKey, usage)
96 if err != nil {
97 return nil, err
98 }
99 return e.RandomToKey(r), nil
100}
101
102// EncryptData encrypts the data provided.
103func (e Des3CbcSha1Kd) EncryptData(key, data []byte) ([]byte, []byte, error) {
104 return rfc3961.DES3EncryptData(key, data, e)
105}
106
107// EncryptMessage encrypts the message provided and concatenates it with the integrity hash to create an encrypted message.
108func (e Des3CbcSha1Kd) EncryptMessage(key, message []byte, usage uint32) ([]byte, []byte, error) {
109 return rfc3961.DES3EncryptMessage(key, message, usage, e)
110}
111
112// DecryptData decrypts the data provided.
113func (e Des3CbcSha1Kd) DecryptData(key, data []byte) ([]byte, error) {
114 return rfc3961.DES3DecryptData(key, data, e)
115}
116
117// DecryptMessage decrypts the message provided and verifies the integrity of the message.
118func (e Des3CbcSha1Kd) DecryptMessage(key, ciphertext []byte, usage uint32) ([]byte, error) {
119 return rfc3961.DES3DecryptMessage(key, ciphertext, usage, e)
120}
121
122// VerifyIntegrity checks the integrity of the plaintext message.
123func (e Des3CbcSha1Kd) VerifyIntegrity(protocolKey, ct, pt []byte, usage uint32) bool {
124 return rfc3961.VerifyIntegrity(protocolKey, ct, pt, usage, e)
125}
126
127// GetChecksumHash returns a keyed checksum hash of the bytes provided.
128func (e Des3CbcSha1Kd) GetChecksumHash(protocolKey, data []byte, usage uint32) ([]byte, error) {
129 return common.GetHash(data, protocolKey, common.GetUsageKc(usage), e)
130}
131
132// VerifyChecksum compares the checksum of the message bytes is the same as the checksum provided.
133func (e Des3CbcSha1Kd) VerifyChecksum(protocolKey, data, chksum []byte, usage uint32) bool {
134 c, err := e.GetChecksumHash(protocolKey, data, usage)
135 if err != nil {
136 return false
137 }
138 return hmac.Equal(chksum, c)
139}