Init

1 files changed, 94 insertions, 0 deletions

diff --git a/main.go b/main.go
new file mode 100644
index 0000000..385c042
--- /dev/null
+++ b/main.go
@@ -0,0 +1,94 @@
+package main
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"os"
+
+	"github.com/joho/godotenv"
+)
+
+func main() {
+	err := godotenv.Load()
+	if err != nil {
+		log.Fatal("Error loading .env file")
+	}
+
+	base64kek := os.Getenv("SECRET_KEY")
+
+	kek, err := base64.StdEncoding.DecodeString(base64kek)
+	if err != nil {
+		panic(err)
+	}
+
+	dek := GenCipherKey()
+
+	encryptedDek, err := Encrypt(dek, kek)
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println("edek", encryptedDek)
+
+	cipherText, err := Encrypt([]byte("hello"), dek)
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println("ciphertext", cipherText)
+}
+
+type CipherKey []byte
+
+func GenCipherKey() CipherKey {
+	key := make([]byte, 32)
+	if _, err := io.ReadFull(rand.Reader, key); err != nil {
+		log.Fatalf("random key gen: %v", err)
+	}
+	return CipherKey(key)
+}
+
+func Encrypt(plaintext []byte, key CipherKey) ([]byte, error) {
+	c, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+
+	gcm, err := cipher.NewGCM(c)
+	if err != nil {
+		return nil, err
+	}
+
+	nonce := make([]byte, gcm.NonceSize())
+	if _, err = io.ReadFull(rand.Reader, nonce); err != nil {
+		return nil, err
+	}
+
+	return gcm.Seal(nonce, nonce, plaintext, nil), nil
+}
+
+func Decrypt(ciphertext []byte, key CipherKey) ([]byte, error) {
+	c, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+
+	gcm, err := cipher.NewGCM(c)
+	if err != nil {
+		return nil, err
+	}
+
+	nonceSize := gcm.NonceSize()
+	if len(ciphertext) < nonceSize {
+		return nil, errors.New("ciphertext too short")
+	}
+
+	nonce, ciphertext := ciphertext[:nonceSize], ciphertext[nonceSize:]
+	return gcm.Open(nil, nonce, ciphertext, nil)
+}