65 lines
1.7 KiB
Go
65 lines
1.7 KiB
Go
package storage
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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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"fmt"
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"math/rand"
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)
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const letterSet = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
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func GenerateEncryptionKey() []byte {
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return append(generateRandomBytes(16), generateRandomBytes(16)...)
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}
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func generateRandomBytes(size int) []byte {
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b := make([]byte, size)
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for i := range b {
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b[i] = letterSet[rand.Int63()%int64(len(letterSet))]
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}
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return b
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}
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func fillLastBlock(rawText []byte, blockSize int) []byte {
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padding := blockSize - len(rawText)%blockSize
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padText := bytes.Repeat([]byte{byte(padding)}, padding)
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return append(rawText, padText...)
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}
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func EncryptData(data, fullKey []byte) ([]byte, error) {
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if len(fullKey) != 32 {
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return nil, errors.New("wrong format of encryption key")
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}
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key, iv := fullKey[:16], fullKey[16:]
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// Fill the last block of data by zeros
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paddedData := fillLastBlock(data, aes.BlockSize)
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// Create new AES cipher with CBC encryptor
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, fmt.Errorf("cbc encryptor failed: %s", err)
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}
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mode := cipher.NewCBCEncrypter(block, iv)
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// Encrypting data
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ciphertext := make([]byte, len(paddedData))
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mode.CryptBlocks(ciphertext, paddedData)
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// Return encrypted data
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return ciphertext, nil
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}
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func DecryptData(data, fullKey []byte) ([]byte, error) {
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if len(fullKey) != 32 {
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return nil, errors.New("wrong format of encryption key")
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}
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key, iv := fullKey[:16], fullKey[16:]
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, fmt.Errorf("cbc encryptor failed: %s", err)
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}
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cbc := cipher.NewCBCDecrypter(block, iv)
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res := make([]byte, len(data))
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cbc.CryptBlocks(res, data)
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return res, nil
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}
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