/
filter_aesv2.go
69 lines (56 loc) · 1.5 KB
/
filter_aesv2.go
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/*
* This file is subject to the terms and conditions defined in
* file 'LICENSE.md', which is part of this source code package.
*/
package crypt
import (
"fmt"
"github.com/xwc1125/gopdf/common"
)
func init() {
registerFilter("AESV2", newFilterAESV2)
}
// NewFilterAESV2 creates an AES-based filter with a 128 bit key (AESV2).
func NewFilterAESV2() Filter {
f, err := newFilterAESV2(FilterDict{})
if err != nil {
panic(err)
}
return f
}
func newFilterAESV2(d FilterDict) (Filter, error) {
if d.Length == 128 {
common.Log.Debug("AESV2 crypt filter length appears to be in bits rather than bytes - assuming bits (%d)", d.Length)
d.Length /= 8
}
if d.Length != 0 && d.Length != 16 {
return nil, fmt.Errorf("invalid AESV2 crypt filter length (%d)", d.Length)
}
return filterAESV2{}, nil
}
var _ Filter = filterAESV2{}
// filterAESV2 is an AES-based filter (128 bit key, PDF 1.6)
type filterAESV2 struct {
filterAES
}
// PDFVersion implements Filter interface.
func (filterAESV2) PDFVersion() [2]int {
return [2]int{1, 5}
}
// HandlerVersion implements Filter interface.
func (filterAESV2) HandlerVersion() (V, R int) {
V, R = 4, 4
return
}
// Name implements Filter interface.
func (filterAESV2) Name() string {
return "AESV2"
}
// KeyLength implements Filter interface.
func (filterAESV2) KeyLength() int {
return 128 / 8
}
// MakeKey implements Filter interface.
func (filterAESV2) MakeKey(objNum, genNum uint32, ekey []byte) ([]byte, error) {
return makeKeyV2(objNum, genNum, ekey, true)
}