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mirror of https://github.com/OpenDiablo2/OpenDiablo2 synced 2024-11-17 01:51:14 -05:00
OpenDiablo2/d2common/d2fileformats/d2mpq/crypto.go
Intyre db83814527
d2mpq refactored (#1020)
* d2mpq refactor

* d2mpq refactor last standing lint error

* d2mpq refactor: less linter noise

* d2mpq refactor: more linter issues
2021-01-08 12:46:11 -08:00

132 lines
3.1 KiB
Go

package d2mpq
import (
"encoding/binary"
"io"
"strings"
)
var cryptoBuffer [0x500]uint32 //nolint:gochecknoglobals // will fix later..
var cryptoBufferReady bool //nolint:gochecknoglobals // will fix later..
func cryptoLookup(index uint32) uint32 {
if !cryptoBufferReady {
cryptoInitialize()
cryptoBufferReady = true
}
return cryptoBuffer[index]
}
//nolint:gomnd // Decryption magic
func cryptoInitialize() {
seed := uint32(0x00100001)
for index1 := 0; index1 < 0x100; index1++ {
index2 := index1
for i := 0; i < 5; i++ {
seed = (seed*125 + 3) % 0x2AAAAB
temp1 := (seed & 0xFFFF) << 0x10
seed = (seed*125 + 3) % 0x2AAAAB
temp2 := seed & 0xFFFF
cryptoBuffer[index2] = temp1 | temp2
index2 += 0x100
}
}
}
//nolint:gomnd // Decryption magic
func decrypt(data []uint32, seed uint32) {
seed2 := uint32(0xeeeeeeee)
for i := 0; i < len(data); i++ {
seed2 += cryptoLookup(0x400 + (seed & 0xff))
result := data[i]
result ^= seed + seed2
seed = ((^seed << 21) + 0x11111111) | (seed >> 11)
seed2 = result + seed2 + (seed2 << 5) + 3
data[i] = result
}
}
//nolint:gomnd // Decryption magic
func decryptBytes(data []byte, seed uint32) {
seed2 := uint32(0xEEEEEEEE)
for i := 0; i < len(data)-3; i += 4 {
seed2 += cryptoLookup(0x400 + (seed & 0xFF))
result := binary.LittleEndian.Uint32(data[i : i+4])
result ^= seed + seed2
seed = ((^seed << 21) + 0x11111111) | (seed >> 11)
seed2 = result + seed2 + (seed2 << 5) + 3
data[i+0] = uint8(result & 0xff)
data[i+1] = uint8((result >> 8) & 0xff)
data[i+2] = uint8((result >> 16) & 0xff)
data[i+3] = uint8((result >> 24) & 0xff)
}
}
//nolint:gomnd // Decryption magic
func decryptTable(r io.Reader, size uint32, name string) ([]uint32, error) {
seed := hashString(name, 3)
seed2 := uint32(0xEEEEEEEE)
size *= 4
table := make([]uint32, size)
buf := make([]byte, 4)
for i := uint32(0); i < size; i++ {
seed2 += cryptoBuffer[0x400+(seed&0xff)]
if _, err := r.Read(buf); err != nil {
return table, err
}
result := binary.LittleEndian.Uint32(buf)
result ^= seed + seed2
seed = ((^seed << 21) + 0x11111111) | (seed >> 11)
seed2 = result + seed2 + (seed2 << 5) + 3
table[i] = result
}
return table, nil
}
func hashFilename(key string) uint64 {
a, b := hashString(key, 1), hashString(key, 2)
return uint64(a)<<32 | uint64(b)
}
//nolint:gomnd // Decryption magic
func hashString(key string, hashType uint32) uint32 {
seed1 := uint32(0x7FED7FED)
seed2 := uint32(0xEEEEEEEE)
/* prepare seeds. */
for _, char := range strings.ToUpper(key) {
seed1 = cryptoLookup((hashType*0x100)+uint32(char)) ^ (seed1 + seed2)
seed2 = uint32(char) + seed1 + seed2 + (seed2 << 5) + 3
}
return seed1
}
//nolint:unused,deadcode,gomnd // will use this for creating mpq's
func encrypt(data []uint32, seed uint32) {
seed2 := uint32(0xeeeeeeee)
for i := 0; i < len(data); i++ {
seed2 += cryptoLookup(0x400 + (seed & 0xff))
result := data[i]
result ^= seed + seed2
seed = ((^seed << 21) + 0x11111111) | (seed >> 11)
seed2 = data[i] + seed2 + (seed2 << 5) + 3
data[i] = result
}
}