From 11fb037e7e7d84405b3bed9de2aa500e49d9502d Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher
Date: Sat, 5 Sep 2015 20:30:20 +0200
Subject: Cleanup and rename files

---
 cryptfs/cryptfs.go | 172 +----------------------------------------------------
 1 file changed, 2 insertions(+), 170 deletions(-)

(limited to 'cryptfs/cryptfs.go')

diff --git a/cryptfs/cryptfs.go b/cryptfs/cryptfs.go
index d385a77..9ec511a 100644
--- a/cryptfs/cryptfs.go
+++ b/cryptfs/cryptfs.go
@@ -1,21 +1,16 @@
 package cryptfs
 
+// CryptFS is the crypto backend of GoCryptFS
+
 import (
 	"crypto/cipher"
 	"crypto/aes"
-	"fmt"
-	"strings"
-	"encoding/base64"
-	"errors"
 )
 
 const (
 	NONCE_LEN = 12
 	AUTH_TAG_LEN = 16
 	DEFAULT_PLAINBS = 4096
-
-	ENCRYPT = true
-	DECRYPT = false
 )
 
 type CryptFS struct {
@@ -45,169 +40,6 @@ func NewCryptFS(key [16]byte) *CryptFS {
 	}
 }
 
-/*
-func (fs *CryptFS) NewFile(f *os.File) *CryptFile {
-	return &CryptFile {
-		file: f,
-		gcm: fs.gcm,
-		plainBS: fs.plainBS,
-		cipherBS: fs.cipherBS,
-	}
-}
-*/
-
 func (be *CryptFS) PlainBS() uint64 {
 	return be.plainBS
 }
-
-// DecryptName - decrypt filename
-func (be *CryptFS) decryptName(cipherName string) (string, error) {
-
-	bin, err := base64.URLEncoding.DecodeString(cipherName)
-	if err != nil {
-		return "", err
-	}
-
-	if len(bin) % aes.BlockSize != 0 {
-		return "", errors.New(fmt.Sprintf("Name len=%d is not a multiple of 16", len(bin)))
-	}
-
-	iv := make([]byte, aes.BlockSize) // TODO ?
-	cbc := cipher.NewCBCDecrypter(be.blockCipher, iv)
-	cbc.CryptBlocks(bin, bin)
-
-	bin, err = be.unPad16(bin)
-	if err != nil {
-		return "", err
-	}
-
-	plain := string(bin)
-	return plain, err
-}
-
-// EncryptName - encrypt filename
-func (be *CryptFS) encryptName(plainName string) string {
-
-	bin := []byte(plainName)
-	bin = be.pad16(bin)
-
-	iv := make([]byte, 16) // TODO ?
-	cbc := cipher.NewCBCEncrypter(be.blockCipher, iv)
-	cbc.CryptBlocks(bin, bin)
-
-	cipherName64 := base64.URLEncoding.EncodeToString(bin)
-
-	return cipherName64
-}
-
-// TranslatePath - encrypt or decrypt path. Just splits the string on "/"
-// and hands the parts to EncryptName() / DecryptName()
-func (be *CryptFS) translatePath(path string, op bool) (string, error) {
-	var err error
-
-	// Empty string means root directory
-	if path == "" {
-		return path, err
-	}
-
-	// Run operation on each path component
-	var translatedParts []string
-	parts := strings.Split(path, "/")
-	for _, part := range parts {
-		var newPart string
-		if op == ENCRYPT {
-			newPart = be.encryptName(part)
-		} else {
-			newPart, err = be.decryptName(part)
-			if err != nil {
-				return "", err
-			}
-		}
-		translatedParts = append(translatedParts, newPart)
-	}
-
-	return strings.Join(translatedParts, "/"), err
-}
-
-// EncryptPath - encrypt filename or path. Just hands it to TranslatePath().
-func (be *CryptFS) EncryptPath(path string) string {
-	newPath, _ := be.translatePath(path, ENCRYPT)
-	return newPath
-}
-
-// DecryptPath - decrypt filename or path. Just hands it to TranslatePath().
-func (be *CryptFS) DecryptPath(path string) (string, error) {
-	return be.translatePath(path, DECRYPT)
-}
-
-// PlainSize - calculate plaintext size from ciphertext size
-func (be *CryptFS) PlainSize(size uint64) uint64 {
-	// Zero sized files stay zero-sized
-	if size > 0 {
-		overhead := be.cipherBS - be.plainBS
-		nBlocks := (size + be.cipherBS - 1) / be.cipherBS
-		size -= nBlocks * overhead
-	}
-	return size
-}
-
-
-// plainSizeFromCipherSize - calculate plaintext size from ciphertext size
-func (be *CryptFS) plainSizeFromCipherSize(size int64) int64 {
-	if size > 0 {
-
-	}
-	return size
-}
-// pad16 - pad filename to 16 byte blocks using standard PKCS#7 padding
-// https://tools.ietf.org/html/rfc5652#section-6.3
-func (be *CryptFS) pad16(orig []byte) (padded []byte) {
-	oldLen := len(orig)
-	if oldLen == 0 {
-		panic("Padding zero-length string makes no sense")
-	}
-	padLen := aes.BlockSize - oldLen % aes.BlockSize
-	if padLen == 0 {
-		padLen = aes.BlockSize
-	}
-	newLen := oldLen + padLen
-	padded = make([]byte, newLen)
-	copy(padded, orig)
-	padByte := byte(padLen)
-	for i := oldLen; i < newLen; i++ {
-		padded[i] = padByte
-	}
-	return padded
-}
-
-// unPad16 - remove padding
-func (be *CryptFS) unPad16(orig []byte) ([]byte, error) {
-	oldLen := len(orig)
-	if oldLen % aes.BlockSize != 0 {
-		return nil, errors.New("Unaligned size")
-	}
-	// The last byte is always a padding byte
-	padByte := orig[oldLen -1]
-	// The padding byte's value is the padding length
-	padLen := int(padByte)
-	// Padding must be at least 1 byte
-	if padLen <= 0 {
-		return nil, errors.New("Padding cannot be zero-length")
-	}
-	// Larger paddings make no sense
-	if padLen > aes.BlockSize {
-		return nil, errors.New("Padding cannot be larger than 16")
-	}
-	// All padding bytes must be identical
-	for i := oldLen - padLen; i < oldLen; i++ {
-		if orig[i] != padByte {
-			return nil, errors.New(fmt.Sprintf("Padding byte at i=%d is invalid", i))
-		}
-	}
-	newLen := oldLen - padLen
-	// Padding an empty string makes no sense
-	if newLen == 0 {
-		return nil, errors.New("Unpadded length is zero")
-	}
-	return orig[0:newLen], nil
-}
-- 
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