move package encrypt from quiz common

encrypt/encrypted.go

@@ -0,0 +1,57 @@
+package encrypt
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+)
+
+type Encrypt struct {
+	pubKey  string
+	privKey string
+}
+
+func NewEncrypt(pubKey, privKey string) *Encrypt {
+	return &Encrypt{pubKey: pubKey, privKey: privKey}
+}
+
+func (e *Encrypt) EncryptStr(str string) ([]byte, error) {
+	block, _ := pem.Decode([]byte(e.pubKey))
+	if block == nil {
+		return nil, errors.New("failed to parse PEM block containing the public key")
+	}
+	pub, err := x509.ParsePKIXPublicKey(block.Bytes)
+	if err != nil {
+		return nil, err
+	}
+	rsaPubKey, ok := pub.(*rsa.PublicKey)
+	if !ok {
+		return nil, errors.New("failed to parse RSA public key")
+	}
+
+	shifr, err := rsa.EncryptPKCS1v15(rand.Reader, rsaPubKey, []byte(str))
+	if err != nil {
+		return nil, err
+	}
+	return shifr, nil
+}
+
+func (e *Encrypt) DecryptStr(shifr []byte) (string, error) {
+	block, _ := pem.Decode([]byte(e.privKey))
+	if block == nil {
+		return "", errors.New("failed to parse PEM block containing the private key")
+	}
+
+	priv, err := x509.ParsePKCS1PrivateKey(block.Bytes)
+	if err != nil {
+		return "", err
+	}
+
+	res, err := rsa.DecryptPKCS1v15(rand.Reader, priv, shifr)
+	if err != nil {
+		return "", err
+	}
+	return string(res), nil
+}