DroidFS/app/libgocryptfs/gocryptfs_internal/jacobsa_crypto/common/pad_block.go
2020-07-17 22:12:20 +02:00

37 lines
1.1 KiB
Go

// Copyright 2012 Aaron Jacobs. All Rights Reserved.
// Author: aaronjjacobs@gmail.com (Aaron Jacobs)
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package common
import (
"crypto/aes"
)
// PadBlock pads a string of bytes less than 16 bytes long to a full block size
// by appending a one bit followed by zero bits. This is the padding function
// used in RFCs 4493 and 5297.
func PadBlock(block []byte) []byte {
blockLen := len(block)
if blockLen >= aes.BlockSize {
panic("PadBlock input must be less than 16 bytes.")
}
result := make([]byte, aes.BlockSize)
copy(result, block)
result[blockLen] = 0x80
return result
}