/
xxtea.go
97 lines (87 loc) · 2.07 KB
/
xxtea.go
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package xxtea
/*
#include <stdio.h>
#define MX (z>>5^y<<2) + (y>>3^z<<4)^(sum^y) + (k[p&3^e]^z);
long btea(int* v, int n, const int* k) {
unsigned int z=v[n-1], y=v[0], sum=0, e, DELTA=0x9e3779b9;
long p, q ;
if (n > 1) {
q = 6 + 52/n;
while (q-- > 0) {
sum += DELTA;
e = (sum >> 2) & 3;
for (p=0; p<n-1; p++) y = v[p+1], z = v[p] += MX;
y = v[0];
z = v[n-1] += MX;
}
return 0 ;
} else if (n < -1) {
n = -n;
q = 6 + 52/n;
sum = q*DELTA ;
while (sum != 0) {
e = (sum >> 2) & 3;
for (p=n-1; p>0; p--) z = v[p-1], y = v[p] -= MX;
z = v[n-1];
y = v[0] -= MX;
sum -= DELTA;
}
return 0;
}
return 1;
}
*/
import "C"
import (
"bytes"
"errors"
"fmt"
"unsafe"
)
var (
KeyError = errors.New("key_error")
ValueError = errors.New("value_error")
XXTeaError = errors.New("xxtea_error")
)
func PKCS5Padding(ciphertext []byte, blockSize int) []byte {
padding := blockSize - len(ciphertext)%blockSize
padtext := bytes.Repeat([]byte{byte(padding)}, padding)
return append(ciphertext, padtext...)
}
func PKCS5UnPadding(origData []byte) []byte {
length := len(origData)
unpadding := int(origData[length-1])
return origData[:(length - unpadding)]
}
func Encrypt(v, k []byte) ([]byte, error) {
if len(k) != 16 {
return nil, KeyError
}
if len(v) < 8 {
v = PKCS5Padding(v, 8)
} else {
v = PKCS5Padding(v, 4)
}
r := C.btea((*C.int)(unsafe.Pointer(&v[0])), C.int(len(v)/4), (*C.int)(unsafe.Pointer(&k[0])))
if r != 0 {
return nil, XXTeaError
}
return v, nil
}
func Decrypt(v, k []byte) ([]byte, error) {
if len(k) != 16 {
return nil, KeyError
}
r := C.btea((*C.int)(unsafe.Pointer(&v[0])), C.int(-len(v)/4), (*C.int)(unsafe.Pointer(&k[0])))
if r != 0 {
return nil, XXTeaError
}
return PKCS5UnPadding(v), nil
}
func main() {
k := []byte("1234567890123456")
v, err := Encrypt([]byte("hello"), k)
fmt.Println(v, err)
v, err = Decrypt(v, k)
fmt.Printf("%s, %v\n", v, err)
}