/
cipher.go
151 lines (124 loc) · 3.74 KB
/
cipher.go
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package proxy
import (
. "../config"
"../logg"
"crypto/cipher"
"encoding/binary"
"encoding/hex"
)
const IV_LENGTH = 16
var primes = []int16{
11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71,
73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151,
157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239,
241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337,
347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433,
439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 503, 509, 521, 523, 541,
547, 557, 563, 569, 571, 577, 587, 593, 599, 601, 607, 613, 617, 619, 631, 641,
643, 647, 653, 659, 661, 673, 677, 683, 691, 701, 709, 719, 727, 733, 739, 743,
751, 757, 761, 769, 773, 787, 797, 809, 811, 821, 823, 827, 829, 839, 853, 857,
859, 863, 877, 881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953, 967, 971,
977, 983, 991, 997, 1009, 1013, 1019, 1021, 1031, 1033, 1039, 1049, 1051, 1061, 1063, 1069,
1087, 1091, 1093, 1097, 1103, 1109, 1117, 1123, 1129, 1151, 1153, 1163, 1171, 1181, 1187, 1193,
1201, 1213, 1217, 1223, 1229, 1231, 1237, 1249, 1259, 1277, 1279, 1283, 1289, 1291, 1297, 1301,
1303, 1307, 1319, 1321, 1327, 1361, 1367, 1373, 1381, 1399, 1409, 1423, 1427, 1429, 1433, 1439,
1447, 1451, 1453, 1459, 1471, 1481, 1483, 1487, 1489, 1493, 1499, 1511, 1523, 1531, 1543, 1549,
1553, 1559, 1567, 1571, 1579, 1583, 1597, 1601, 1607, 1609, 1613, 1619, 1621, 1627, 1637, 1657,
}
type InplaceCTR struct {
b cipher.Block
ctr []byte
out []byte
outUsed int
}
const streamBufferSize = 512
// From src/crypto/cipher/ctr.go
func (x *InplaceCTR) XorBuffer(buf []byte) {
for i := 0; i < len(buf); i++ {
if x.outUsed >= len(x.out)-x.b.BlockSize() {
// refill
remain := len(x.out) - x.outUsed
copy(x.out, x.out[x.outUsed:])
x.out = x.out[:cap(x.out)]
bs := x.b.BlockSize()
for remain <= len(x.out)-bs {
x.b.Encrypt(x.out[remain:], x.ctr)
remain += bs
// Increment counter
for i := len(x.ctr) - 1; i >= 0; i-- {
x.ctr[i]++
if x.ctr[i] != 0 {
break
}
}
}
x.out = x.out[:remain]
x.outUsed = 0
}
buf[i] ^= x.out[x.outUsed]
x.outUsed++
}
}
func GetCipherStream(key []byte) *InplaceCTR {
if key == nil {
return nil
}
if len(key) != IV_LENGTH {
logg.E("[AES] iv is not 128bit long")
return nil
}
return &InplaceCTR{
b: G_KeyBlock,
ctr: key,
out: make([]byte, 0, streamBufferSize),
outUsed: 0,
}
}
func _AXor(blk cipher.Block, iv, buf []byte) []byte {
bsize := blk.BlockSize()
x := make([]byte, len(buf)/bsize*bsize+bsize)
for i := 0; i < len(x); i += bsize {
blk.Encrypt(x[i:], iv)
for i := len(iv) - 1; i >= 0; i-- {
if iv[i]++; iv[i] != 0 {
break
}
}
}
for i := 0; i < len(buf); i++ {
buf[i] ^= x[i]
}
return buf
}
func generateIV(s, s2 byte) []byte {
ret := make([]byte, IV_LENGTH)
var mul uint32 = uint32(primes[s]) * uint32(primes[s2])
var seed uint32 = binary.LittleEndian.Uint32(G_KeyBytes[:4])
for i := 0; i < IV_LENGTH/4; i++ {
seed = (mul * seed) % 0x7fffffff
binary.LittleEndian.PutUint32(ret[i*4:], seed)
}
return ret
}
func AEncrypt(buf []byte) []byte {
r := NewRand()
b, b2 := byte(r.Intn(256)), byte(r.Intn(256))
return append(_AXor(G_KeyBlock, generateIV(b, b2), buf), b, b2)
}
func ADecrypt(buf []byte) []byte {
if len(buf) < 2 {
return buf
}
b, b2 := byte(buf[len(buf)-2]), byte(buf[len(buf)-1])
return _AXor(G_KeyBlock, generateIV(b, b2), buf[:len(buf)-2])
}
func AEncryptString(text string) string {
return hex.EncodeToString(AEncrypt([]byte(text)))
}
func ADecryptString(text string) string {
buf, err := hex.DecodeString(text)
if err != nil {
return ""
}
return string(ADecrypt(buf))
}