add encryption and get page

internal/crypto/cipher.go

@@ -0,0 +1,32 @@
+package crypto
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/hex"
+	"fmt"
+)
+
+var (
+	someDumbKey = []byte("9530e001b619e8e98a889055f06821bb")
+)
+
+func Encrypt(plaintext string) (hexed string, err error) {
+	aes, err := aes.NewCipher(someDumbKey)
+	if err != nil {
+		return "", fmt.Errorf("making new cipher: %w", err)
+	}
+	gcm, err := cipher.NewGCM(aes)
+	if err != nil {
+		return "", fmt.Errorf("making new gcm: %w", err)
+	}
+
+	nonce := make([]byte, gcm.NonceSize())
+	_, err = rand.Read(nonce)
+	if err != nil {
+		return "", fmt.Errorf("generating nonce: %w", err)
+	}
+	outvalue := gcm.Seal(nonce, nonce, []byte(plaintext), nil)
+	return hex.EncodeToString(outvalue), nil
+}