62 lines
1.6 KiB
Go
62 lines
1.6 KiB
Go
package main
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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"encoding/hex"
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"fmt"
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"io"
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)
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func getKey(key []byte) (string,error) {
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bytes := make([]byte, 32) //generate a random 32 byte key for AES-256
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if _, err := rand.Read(bytes); err != nil {
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return "", err
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}
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return hex.EncodeToString(bytes),nil
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}
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func encrypt(text string, keytext string) (string, error) {
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key, _ := hex.DecodeString(keytext)
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plaintext := []byte(text)
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block, err := aes.NewCipher(key)
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if err != nil {
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return "",err
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}
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//GCM - https://en.wikipedia.org/wiki/Galois/Counter_Mode
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//https://golang.org/pkg/crypto/cipher/#NewGCM
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aesGCM, 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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nonce := make([]byte, aesGCM.NonceSize())
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if _, err = io.ReadFull(rand.Reader, nonce); err != nil {
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return "",err
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}
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//Encrypt the data using aesGCM.Seal
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//Since we don't want to save the nonce somewhere else in this case, we add it as a prefix to the encrypted data. The first nonce argument in Seal is the prefix.
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ciphertext := aesGCM.Seal(nonce, nonce, plaintext, nil)
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return fmt.Sprintf("%x", ciphertext),nil
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}
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func decrypt(encodedtext string, keytext string) (string,error) {
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key, _ := hex.DecodeString(keytext)
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enc, _ := hex.DecodeString(encodedtext)
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block, err := aes.NewCipher(key)
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if err != nil {
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return "",err
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}
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aesGCM, 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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nonceSize := aesGCM.NonceSize()
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//Extract the nonce from the encrypted data
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nonce, ciphertext := enc[:nonceSize], enc[nonceSize:]
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//Decrypt the data
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text, err := aesGCM.Open(nil, nonce, ciphertext, nil)
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if err != nil {
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return "",err
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}
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return fmt.Sprintf("%s", text), nil
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} |