45 lines
832 B
Go
45 lines
832 B
Go
package main
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import (
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"crypto/aes"
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"crypto/cipher"
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"encoding/base64"
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"errors"
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"log"
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"os"
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"strings"
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)
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func main() {
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key := os.Args[1]
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value := os.Args[2]
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log.Println(aesDec(key, value))
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}
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func aesDec(key, payload string) (string, error) {
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if len(key) == 0 {
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return "", errors.New("key required")
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}
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key = strings.Repeat(key, 32)[:32]
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ciphertext, err := base64.StdEncoding.DecodeString(payload)
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if err != nil {
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return "", err
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}
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block, err := aes.NewCipher([]byte(key))
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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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log.Println(gcm.NonceSize())
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if len(ciphertext) < gcm.NonceSize() {
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return "", errors.New("short ciphertext")
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}
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b, err := gcm.Open(nil, ciphertext[:gcm.NonceSize()], ciphertext[gcm.NonceSize():], nil)
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return string(b), err
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}
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