Pragya Arya | 324337e | 2020-02-20 14:35:08 +0530 | [diff] [blame] | 1 | package crypto |
| 2 | |
| 3 | import ( |
| 4 | "bytes" |
| 5 | "crypto/hmac" |
| 6 | "crypto/md5" |
| 7 | "hash" |
| 8 | "io" |
| 9 | |
| 10 | "golang.org/x/crypto/md4" |
| 11 | "gopkg.in/jcmturner/gokrb5.v7/crypto/rfc3961" |
| 12 | "gopkg.in/jcmturner/gokrb5.v7/crypto/rfc4757" |
| 13 | "gopkg.in/jcmturner/gokrb5.v7/iana/chksumtype" |
| 14 | "gopkg.in/jcmturner/gokrb5.v7/iana/etypeID" |
| 15 | ) |
| 16 | |
| 17 | //http://grepcode.com/file/repository.grepcode.com/java/root/jdk/openjdk/8u40-b25/sun/security/krb5/internal/crypto/dk/ArcFourCrypto.java#ArcFourCrypto.encrypt%28byte%5B%5D%2Cint%2Cbyte%5B%5D%2Cbyte%5B%5D%2Cbyte%5B%5D%2Cint%2Cint%29 |
| 18 | |
| 19 | // RC4HMAC implements Kerberos encryption type aes256-cts-hmac-sha1-96 |
| 20 | type RC4HMAC struct { |
| 21 | } |
| 22 | |
| 23 | // GetETypeID returns the EType ID number. |
| 24 | func (e RC4HMAC) GetETypeID() int32 { |
| 25 | return etypeID.RC4_HMAC |
| 26 | } |
| 27 | |
| 28 | // GetHashID returns the checksum type ID number. |
| 29 | func (e RC4HMAC) GetHashID() int32 { |
| 30 | return chksumtype.KERB_CHECKSUM_HMAC_MD5 |
| 31 | } |
| 32 | |
| 33 | // GetKeyByteSize returns the number of bytes for key of this etype. |
| 34 | func (e RC4HMAC) GetKeyByteSize() int { |
| 35 | return 16 |
| 36 | } |
| 37 | |
| 38 | // GetKeySeedBitLength returns the number of bits for the seed for key generation. |
| 39 | func (e RC4HMAC) GetKeySeedBitLength() int { |
| 40 | return e.GetKeyByteSize() * 8 |
| 41 | } |
| 42 | |
| 43 | // GetHashFunc returns the hash function for this etype. |
| 44 | func (e RC4HMAC) GetHashFunc() func() hash.Hash { |
| 45 | return md5.New |
| 46 | } |
| 47 | |
| 48 | // GetMessageBlockByteSize returns the block size for the etype's messages. |
| 49 | func (e RC4HMAC) GetMessageBlockByteSize() int { |
| 50 | return 1 |
| 51 | } |
| 52 | |
| 53 | // GetDefaultStringToKeyParams returns the default key derivation parameters in string form. |
| 54 | func (e RC4HMAC) GetDefaultStringToKeyParams() string { |
| 55 | return "" |
| 56 | } |
| 57 | |
| 58 | // GetConfounderByteSize returns the byte count for confounder to be used during cryptographic operations. |
| 59 | func (e RC4HMAC) GetConfounderByteSize() int { |
| 60 | return 8 |
| 61 | } |
| 62 | |
| 63 | // GetHMACBitLength returns the bit count size of the integrity hash. |
| 64 | func (e RC4HMAC) GetHMACBitLength() int { |
| 65 | return md5.Size * 8 |
| 66 | } |
| 67 | |
| 68 | // GetCypherBlockBitLength returns the bit count size of the cypher block. |
| 69 | func (e RC4HMAC) GetCypherBlockBitLength() int { |
| 70 | return 8 // doesn't really apply |
| 71 | } |
| 72 | |
| 73 | // StringToKey returns a key derived from the string provided. |
| 74 | func (e RC4HMAC) StringToKey(secret string, salt string, s2kparams string) ([]byte, error) { |
| 75 | return rfc4757.StringToKey(secret) |
| 76 | } |
| 77 | |
| 78 | // RandomToKey returns a key from the bytes provided. |
| 79 | func (e RC4HMAC) RandomToKey(b []byte) []byte { |
| 80 | r := bytes.NewReader(b) |
| 81 | h := md4.New() |
| 82 | io.Copy(h, r) |
| 83 | return h.Sum(nil) |
| 84 | } |
| 85 | |
| 86 | // EncryptData encrypts the data provided. |
| 87 | func (e RC4HMAC) EncryptData(key, data []byte) ([]byte, []byte, error) { |
| 88 | b, err := rfc4757.EncryptData(key, data, e) |
| 89 | return []byte{}, b, err |
| 90 | } |
| 91 | |
| 92 | // EncryptMessage encrypts the message provided and concatenates it with the integrity hash to create an encrypted message. |
| 93 | func (e RC4HMAC) EncryptMessage(key, message []byte, usage uint32) ([]byte, []byte, error) { |
| 94 | b, err := rfc4757.EncryptMessage(key, message, usage, false, e) |
| 95 | return []byte{}, b, err |
| 96 | } |
| 97 | |
| 98 | // DecryptData decrypts the data provided. |
| 99 | func (e RC4HMAC) DecryptData(key, data []byte) ([]byte, error) { |
| 100 | return rfc4757.DecryptData(key, data, e) |
| 101 | } |
| 102 | |
| 103 | // DecryptMessage decrypts the message provided and verifies the integrity of the message. |
| 104 | func (e RC4HMAC) DecryptMessage(key, ciphertext []byte, usage uint32) ([]byte, error) { |
| 105 | return rfc4757.DecryptMessage(key, ciphertext, usage, false, e) |
| 106 | } |
| 107 | |
| 108 | // DeriveKey derives a key from the protocol key based on the usage value. |
| 109 | func (e RC4HMAC) DeriveKey(protocolKey, usage []byte) ([]byte, error) { |
| 110 | return rfc4757.HMAC(protocolKey, usage), nil |
| 111 | } |
| 112 | |
| 113 | // DeriveRandom generates data needed for key generation. |
| 114 | func (e RC4HMAC) DeriveRandom(protocolKey, usage []byte) ([]byte, error) { |
| 115 | return rfc3961.DeriveRandom(protocolKey, usage, e) |
| 116 | } |
| 117 | |
| 118 | // VerifyIntegrity checks the integrity of the plaintext message. |
| 119 | func (e RC4HMAC) VerifyIntegrity(protocolKey, ct, pt []byte, usage uint32) bool { |
| 120 | return rfc4757.VerifyIntegrity(protocolKey, pt, ct, e) |
| 121 | } |
| 122 | |
| 123 | // GetChecksumHash returns a keyed checksum hash of the bytes provided. |
| 124 | func (e RC4HMAC) GetChecksumHash(protocolKey, data []byte, usage uint32) ([]byte, error) { |
| 125 | return rfc4757.Checksum(protocolKey, usage, data) |
| 126 | } |
| 127 | |
| 128 | // VerifyChecksum compares the checksum of the message bytes is the same as the checksum provided. |
| 129 | func (e RC4HMAC) VerifyChecksum(protocolKey, data, chksum []byte, usage uint32) bool { |
| 130 | checksum, err := rfc4757.Checksum(protocolKey, usage, data) |
| 131 | if err != nil { |
| 132 | return false |
| 133 | } |
| 134 | return hmac.Equal(checksum, chksum) |
| 135 | } |