publish lancet

cryptor/rsa.go

@@ -0,0 +1,116 @@
+// Copyright 2021 dudaodong@gmail.com. All rights reserved.
+// Use of this source code is governed by MIT license
+
+// Package cryptor implements some util functions to encrypt and decrypt.
+package cryptor
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+	"os"
+)
+
+// GenerateRsaKey make  a rsa private key, and return key file name
+// Generated key file is `rsa_private.pem` and `rsa_public.pem` in current path
+func GenerateRsaKey(keySize int, priKeyFile, pubKeyFile string) {
+	// private key
+	privateKey, err := rsa.GenerateKey(rand.Reader, keySize)
+	if err != nil {
+		panic(err)
+	}
+
+	derText := x509.MarshalPKCS1PrivateKey(privateKey)
+
+	block := pem.Block{
+		Type:  "rsa private key",
+		Bytes: derText,
+	}
+
+	//file,err := os.Create("rsa_private.pem")
+	file, err := os.Create(priKeyFile)
+	if err != nil {
+		panic(err)
+	}
+	pem.Encode(file, &block)
+	file.Close()
+
+	// public key
+	publicKey := privateKey.PublicKey
+
+	derpText, err := x509.MarshalPKIXPublicKey(&publicKey)
+	if err != nil {
+		panic(err)
+	}
+
+	block = pem.Block{
+		Type:  "rsa public key",
+		Bytes: derpText,
+	}
+
+	//file,err = os.Create("rsa_public.pem")
+	file, err = os.Create(pubKeyFile)
+	if err != nil {
+		panic(err)
+	}
+	pem.Encode(file, &block)
+	file.Close()
+}
+
+// RsaEncrypt encrypt data with ras algorithm
+func RsaEncrypt(data []byte, pubKeyFileName string) []byte {
+	file, err := os.Open(pubKeyFileName)
+	if err != nil {
+		panic(err)
+	}
+	fileInfo, err := file.Stat()
+	if err != nil {
+		panic(err)
+	}
+	defer file.Close()
+	buf := make([]byte, fileInfo.Size())
+	file.Read(buf)
+
+	block, _ := pem.Decode(buf)
+
+	pubInterface, err := x509.ParsePKIXPublicKey(block.Bytes)
+	if err != nil {
+		panic(err)
+	}
+	pubKey := pubInterface.(*rsa.PublicKey)
+
+	cipherText, err := rsa.EncryptPKCS1v15(rand.Reader, pubKey, data)
+	if err != nil {
+		panic(err)
+	}
+	return cipherText
+}
+
+// RsaDecrypt decrypt data with ras algorithm
+func RsaDecrypt(data []byte, privateKeyFileName string) []byte {
+	file, err := os.Open(privateKeyFileName)
+	if err != nil {
+		panic(err)
+	}
+	fileInfo, err := file.Stat()
+	if err != nil {
+		panic(err)
+	}
+	buf := make([]byte, fileInfo.Size())
+	defer file.Close()
+	file.Read(buf)
+
+	block, _ := pem.Decode(buf)
+
+	priKey, err := x509.ParsePKCS1PrivateKey(block.Bytes)
+	if err != nil {
+		panic(err)
+	}
+
+	plainText, err := rsa.DecryptPKCS1v15(rand.Reader, priKey, data)
+	if err != nil {
+		panic(err)
+	}
+	return plainText
+}