1 /** 2 * Copyright 2021 Google LLC 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except 5 * in compliance with the License. You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software distributed under the License 10 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express 11 * or implied. See the License for the specific language governing permissions and limitations under 12 * the License. 13 */ 14 // [START hybrid-example] 15 package hybrid; 16 17 import static java.nio.charset.StandardCharsets.UTF_8; 18 19 import com.google.crypto.tink.HybridDecrypt; 20 import com.google.crypto.tink.HybridEncrypt; 21 import com.google.crypto.tink.InsecureSecretKeyAccess; 22 import com.google.crypto.tink.KeysetHandle; 23 import com.google.crypto.tink.TinkJsonProtoKeysetFormat; 24 import com.google.crypto.tink.hybrid.HybridConfig; 25 import java.nio.file.Files; 26 import java.nio.file.Path; 27 import java.nio.file.Paths; 28 29 /** 30 * A command-line utility for hybrid encryption. 31 * 32 * <p>It loads cleartext keys from disk - this is not recommended! 33 * 34 * <p>It requires the following arguments: 35 * 36 * <ul> 37 * <li>mode: either 'encrypt' or 'decrypt'. 38 * <li>key-file: Read the key material from this file. 39 * <li>input-file: Read the input from this file. 40 * <li>output-file: Write the result to this file. 41 * <li>[optional] contex-info: Bind the encryption to this context info. 42 */ 43 public final class HybridExample { main(String[] args)44 public static void main(String[] args) throws Exception { 45 if (args.length != 4 && args.length != 5) { 46 System.err.printf("Expected 4 or 5 parameters, got %d\n", args.length); 47 System.err.println( 48 "Usage: java HybridExample encrypt/decrypt key-file input-file output-file context-info"); 49 System.exit(1); 50 } 51 52 String mode = args[0]; 53 if (!mode.equals("encrypt") && !mode.equals("decrypt")) { 54 System.err.println("Incorrect mode. Please select encrypt or decrypt."); 55 System.exit(1); 56 } 57 Path keyFile = Paths.get(args[1]); 58 Path inputFile = Paths.get(args[2]); 59 byte[] input = Files.readAllBytes(inputFile); 60 Path outputFile = Paths.get(args[3]); 61 byte[] contextInfo = new byte[0]; 62 if (args.length == 5) { 63 contextInfo = args[4].getBytes(UTF_8); 64 } 65 66 // Register all hybrid encryption key types with the Tink runtime. 67 HybridConfig.register(); 68 69 // Read the keyset into a KeysetHandle. 70 KeysetHandle handle = 71 TinkJsonProtoKeysetFormat.parseKeyset( 72 new String(Files.readAllBytes(keyFile), UTF_8), InsecureSecretKeyAccess.get()); 73 74 if (mode.equals("encrypt")) { 75 // Get the primitive. 76 HybridEncrypt encryptor = handle.getPrimitive(HybridEncrypt.class); 77 78 // Use the primitive to encrypt data. 79 byte[] ciphertext = encryptor.encrypt(input, contextInfo); 80 Files.write(outputFile, ciphertext); 81 } else { 82 HybridDecrypt decryptor = handle.getPrimitive(HybridDecrypt.class); 83 84 // Use the primitive to decrypt data. 85 byte[] plaintext = decryptor.decrypt(input, contextInfo); 86 Files.write(outputFile, plaintext); 87 } 88 } 89 HybridExample()90 private HybridExample() {} 91 } 92 // [END hybrid-example] 93