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101 lines
2.0 KiB
101 lines
2.0 KiB
package Encryption
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import (
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"bytes"
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"crypto/aes"
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"crypto/cipher"
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"errors"
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"io"
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"io/ioutil"
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"os"
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)
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func DecryptData(password string, ciphertext []byte) ([]byte, error) {
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var (
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hashedKey []byte
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iv []byte
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encKey []byte
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block cipher.Block
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stream cipher.Stream
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e error
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)
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hashedKey = CreateHash(password)
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if len(ciphertext) == 0 {
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return []byte{}, errors.New("Invalid length")
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}
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iv = ciphertext[:aes.BlockSize]
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encKey = ciphertext[:32+aes.BlockSize][aes.BlockSize:]
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ciphertext = ciphertext[aes.BlockSize+32:]
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block, e = CreateKey(hashedKey)
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if e != nil {
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return []byte{}, e
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}
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stream = cipher.NewCFBDecrypter(block, iv)
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stream.XORKeyStream(encKey, encKey)
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for i := range encKey {
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if encKey[i] != hashedKey[i] {
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return []byte{}, errors.New("Incorrect Password")
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}
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}
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stream.XORKeyStream(ciphertext, ciphertext)
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return ciphertext, nil
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}
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func DecryptFile(password string, FilePath string) error {
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var (
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OldFilePath string
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ciphertext []byte
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plaintext []byte
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plaintextFile *os.File
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e error
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)
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OldFilePath = FilePath[:(len(FilePath) - 4)]
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ciphertext, e = ioutil.ReadFile(FilePath)
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if e != nil {
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return e
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}
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if len(ciphertext) < aes.BlockSize {
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return errors.New("ciphertext too short")
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}
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plaintext, e = DecryptData(password, ciphertext)
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if e != nil {
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return e
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}
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plaintextFile, e = os.Create(OldFilePath)
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if e != nil {
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return e
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}
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_, e = io.Copy(plaintextFile, bytes.NewReader(plaintext))
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if e != nil {
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return e
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}
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os.Remove(FilePath)
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return nil
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}
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func DecryptAndReadFile(password string, FilePath string) (string, error) {
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var (
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ciphertext []byte
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plaintext []byte
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e error
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)
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ciphertext, e = ioutil.ReadFile(FilePath)
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if e != nil {
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return "", e
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}
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if len(ciphertext) < aes.BlockSize {
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return "", errors.New("ciphertext too short")
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}
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plaintext, e = DecryptData(password, ciphertext)
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if e != nil {
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return "", e
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}
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return string(plaintext), nil
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}
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