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v2fly/common/io/encryption.go
2015-09-24 14:55:21 +02:00

55 lines
1.6 KiB
Go

package io
import (
"crypto/cipher"
"io"
)
// CryptionReader is a general purpose reader that applies a stream cipher on top of a regular reader.
type CryptionReader struct {
stream cipher.Stream
reader io.Reader
}
// NewCryptionReader creates a new CryptionReader instance from given stream cipher and reader.
func NewCryptionReader(stream cipher.Stream, reader io.Reader) *CryptionReader {
return &CryptionReader{
stream: stream,
reader: reader,
}
}
// Read reads blocks from underlying reader, and crypt it. The content of blocks is modified in place.
func (reader CryptionReader) Read(blocks []byte) (int, error) {
nBytes, err := reader.reader.Read(blocks)
if nBytes > 0 {
reader.stream.XORKeyStream(blocks[:nBytes], blocks[:nBytes])
}
return nBytes, err
}
// Cryption writer is a general purpose of byte stream writer that applies a stream cipher on top of a regular writer.
type CryptionWriter struct {
stream cipher.Stream
writer io.Writer
}
// NewCryptionWriter creates a new CryptionWriter from given stream cipher and writer.
func NewCryptionWriter(stream cipher.Stream, writer io.Writer) *CryptionWriter {
return &CryptionWriter{
stream: stream,
writer: writer,
}
}
// Crypt crypts the content of blocks without writing them into the underlying writer.
func (writer CryptionWriter) Crypt(blocks []byte) {
writer.stream.XORKeyStream(blocks, blocks)
}
// Write crypts the content of blocks in place, and then writes the give blocks to underlying writer.
func (writer CryptionWriter) Write(blocks []byte) (int, error) {
writer.Crypt(blocks)
return writer.writer.Write(blocks)
}