tools/testing/go/hybrid_decrypt_cli.go

// Copyright 2019 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
///////////////////////////////////////////////////////////////////////////////

// A command-line utility for testing HybridDecrypt-primitives.
// It requires 4 arguments:
//   keyset-file:  name of the file with the keyset to be used for decrypting
//   encrypted-file:  name of the file that contains ciphertext to be decrypted
//   contextinfo-file: name of the file that contains contextinfo used for decryption
//   output-file:  name of the output file for the resulting plaintext
package main

import (
	"io/ioutil"
	"log"
	"os"

	"github.com/google/tink/go/hybrid"
	"github.com/google/tink/go/keyset"
	"github.com/google/tink/go/testkeyset"
)

func main() {
	if len(os.Args) != 5 {
		log.Fatalf("Usage: %s keyset-file encrypted-file contextinfo-file output-file", os.Args[0])
	}

	keysetFilename := os.Args[1]
	etFilename := os.Args[2]
	ctFilename := os.Args[3]
	outputFilename := os.Args[4]

	log.Printf("Using keyset from file %q to decrypt the data in file %q using context info from file %q.\nThe decrypted data will be written to file %q\n",
		keysetFilename, etFilename, ctFilename, outputFilename)

	// Read the keyset.
	f, err := os.Open(keysetFilename)
	if err != nil {
		log.Fatalf("Opening the keyset file failed: %v\n", err)
	}
	reader := keyset.NewBinaryReader(f)
	handle, err := testkeyset.Read(reader)
	if err != nil {
		log.Fatalf("Reading the keyset failed: %v\n", err)
	}

	// Get Primitive
	hybrid, err := hybrid.NewHybridDecrypt(handle)
	if err != nil {
		log.Fatalf("Failed to create primitive: %v\n", err)
	}

	// Read encrypted message
	et, err := ioutil.ReadFile(etFilename)
	if err != nil {
		log.Fatalf("Failed to read encrypted data: %v", err)
	}

	// Read context info
	ct, err := ioutil.ReadFile(ctFilename)
	if err != nil {
		log.Fatalf("Failed to read context info: %v", err)
	}

	log.Printf("Decrypting...\n")
	var pt []byte
	if pt, err = hybrid.Decrypt(et, ct); err != nil {
		log.Fatalf("Error while decrypting: %v\n", err)
	}

	// Write to output file
	if err := ioutil.WriteFile(outputFilename, pt, 0644); err != nil {
		log.Fatalf("Failed to write result to output file. Error: %v", err)
	}
}