89 lines
2.1 KiB
Go
89 lines
2.1 KiB
Go
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package shared
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import (
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"bytes"
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"compress/flate"
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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"encoding/base64"
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"fmt"
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"io"
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)
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type EncryptionClient interface {
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Encrypt(string) (string, error)
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Decrypt(string) (string, error)
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}
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type encryptionClient struct {
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Secret string
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}
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func NewEncryptionClient(secret string) EncryptionClient {
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return &encryptionClient{Secret: secret}
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}
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func compress(text string) ([]byte, error) {
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var compressedBytes bytes.Buffer
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w, err := flate.NewWriter(&compressedBytes, flate.BestCompression)
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w.Write([]byte(text))
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w.Close()
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return compressedBytes.Bytes(), err
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}
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func decompress(compressedBytes []byte) (string, error) {
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reader := flate.NewReader(bytes.NewReader(compressedBytes))
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defer reader.Close()
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textBytes := new(bytes.Buffer)
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_, err := textBytes.ReadFrom(reader)
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return textBytes.String(), err
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}
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// Encrypt method is to encrypt or hide any classified text
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func (e encryptionClient) Encrypt(text string) (string, error) {
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block, err := aes.NewCipher([]byte(e.Secret))
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if err != nil {
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return "", err
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}
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compressedText, err := compress(text)
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if err != nil {
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return "", err
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}
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gcm, err := cipher.NewGCM(block)
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if err != nil {
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return "", err
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}
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bytes := make([]byte, gcm.NonceSize())
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if _, err = io.ReadFull(rand.Reader, bytes); err != nil {
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return "", err
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}
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encodedText := gcm.Seal(bytes, bytes, compressedText, nil)
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return base64.StdEncoding.EncodeToString(encodedText), nil
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}
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// Decrypt method is to extract back the encrypted text
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func (e encryptionClient) Decrypt(text string) (string, error) {
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block, err := aes.NewCipher([]byte(e.Secret))
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if err != nil {
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return "", err
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}
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cipherText, err := base64.StdEncoding.DecodeString(text)
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if err != nil {
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return "", err
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}
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gcm, err := cipher.NewGCM(block)
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if err != nil {
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return "", err
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}
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if len(cipherText) < gcm.NonceSize() {
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return "", fmt.Errorf("text is too small")
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}
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bytes, cipherText := cipherText[:gcm.NonceSize()], cipherText[gcm.NonceSize():]
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compressedTextBytes, err := gcm.Open(nil, bytes, cipherText, nil)
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if err != nil {
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return "", err
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}
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return decompress(compressedTextBytes)
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}
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