131 lines
2.6 KiB
Go
131 lines
2.6 KiB
Go
package crypto
|
|
|
|
import (
|
|
"bytes"
|
|
"crypto/cipher"
|
|
"crypto/des"
|
|
)
|
|
|
|
var (
|
|
DerivationPurposeEnc = []byte{0x01, 0x82}
|
|
DerivationPurposeMac = []byte{0x01, 0x01}
|
|
NullBytes8 = []byte{0, 0, 0, 0, 0, 0, 0, 0}
|
|
)
|
|
|
|
func DeriveKey(cardKey []byte, seq []byte, purpose []byte) ([]byte, error) {
|
|
key24 := resizeKey24(cardKey)
|
|
|
|
derivation := make([]byte, 16)
|
|
copy(derivation, purpose[:2])
|
|
copy(derivation[2:], seq[:2])
|
|
|
|
block, err := des.NewTripleDESCipher(key24)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
ciphertext := make([]byte, 16)
|
|
|
|
mode := cipher.NewCBCEncrypter(block, NullBytes8)
|
|
mode.CryptBlocks(ciphertext, derivation)
|
|
|
|
return ciphertext, nil
|
|
}
|
|
|
|
func VerifyCryptogram(encKey, hostChallenge, cardChallenge, cardCryptogram []byte) (bool, error) {
|
|
data := make([]byte, 0)
|
|
data = append(data, hostChallenge...)
|
|
data = append(data, cardChallenge...)
|
|
paddedData := AppendDESPadding(data)
|
|
calculated, err := Mac3DES(encKey, paddedData, NullBytes8)
|
|
if err != nil {
|
|
return false, err
|
|
}
|
|
|
|
return bytes.Equal(calculated, cardCryptogram), nil
|
|
}
|
|
|
|
func MacFull3DES(key, data, iv []byte) ([]byte, error) {
|
|
data = AppendDESPadding(data)
|
|
|
|
desBlock, err := des.NewCipher(resizeKey8(key))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
des3Block, err := des.NewTripleDESCipher(resizeKey24(key))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
des3IV := iv
|
|
|
|
if len(data) > 8 {
|
|
length := len(data) - 8
|
|
tmp := make([]byte, length)
|
|
mode := cipher.NewCBCEncrypter(desBlock, iv)
|
|
mode.CryptBlocks(tmp, data[:length])
|
|
des3IV = tmp[length-8:]
|
|
}
|
|
|
|
ciphertext := make([]byte, 8)
|
|
|
|
mode := cipher.NewCBCEncrypter(des3Block, des3IV)
|
|
mode.CryptBlocks(ciphertext, data[len(data)-8:])
|
|
|
|
return ciphertext, nil
|
|
}
|
|
|
|
func EncryptICV(macKey, mac []byte) ([]byte, error) {
|
|
block, err := des.NewCipher(resizeKey8(macKey))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
ciphertext := make([]byte, 8)
|
|
mode := cipher.NewCBCEncrypter(block, NullBytes8)
|
|
mode.CryptBlocks(ciphertext, mac)
|
|
|
|
return ciphertext, nil
|
|
}
|
|
|
|
func Mac3DES(key, data, iv []byte) ([]byte, error) {
|
|
key24 := resizeKey24(key)
|
|
|
|
block, err := des.NewTripleDESCipher(key24)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
ciphertext := make([]byte, 24)
|
|
|
|
mode := cipher.NewCBCEncrypter(block, iv)
|
|
mode.CryptBlocks(ciphertext, data)
|
|
|
|
return ciphertext[16:], nil
|
|
}
|
|
|
|
func resizeKey24(key []byte) []byte {
|
|
data := make([]byte, 24)
|
|
copy(data, key[0:16])
|
|
copy(data[16:], key[0:8])
|
|
|
|
return data
|
|
}
|
|
|
|
func resizeKey8(key []byte) []byte {
|
|
return key[:8]
|
|
}
|
|
|
|
func AppendDESPadding(data []byte) []byte {
|
|
length := len(data) + 1
|
|
for ; length%8 != 0; length++ {
|
|
}
|
|
|
|
newData := make([]byte, length)
|
|
copy(newData, data)
|
|
copy(newData[len(data):], []byte{0x80})
|
|
|
|
return newData
|
|
}
|