01.private PrivateKey pri;
02.private PublicKey pub;
03.private Cipher cipher;
04.
05.KeyFactory kf = KeyFactory.getInstance("RSA");
06.byte[] priKeyBytes = Files.readAllBytes(new File("private_key.pem").toPath());
07.PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(priKeyBytes);
08.
09.pri = kf.generatePrivate(spec);
10.byte[] pubKeyBytes = Files.readAllBytes(new File("public_key.pem").toPath());
11.X509EncodedKeySpec pubSpec = new X509EncodedKeySpec(pubKeyBytes);
12.pub = kf.generatePublic(pubSpec);
13.
14.
15.public String createSignature(String message) throws NoSuchAlgorithmException,
16.SignatureException, IOException, InvalidKeySpecException, InvalidKeyException {
17.Signature signature = Signature.getInstance("SHA256withRSA");
18.signature.initSign(pri);
19.signature.update(message.getBytes());
20.byte[] signatureBytes = signature.sign();
21.String encodedSignature = Base64.getEncoder().encodeToString(signatureBytes);
22.return encodedSignature;
23.}
24.
25.
26.public boolean verify(String message, String signature) throws SignatureException,
27.IOException, NoSuchAlgorithmException, InvalidKeySpecException, InvalidKeyException {
28.Signature sign = Signature.getInstance("SHA256withRSA");
29.sign.initVerify(pub);
30.sign.update(message.getBytes("UTF-8"));
31.return sign.verify(Base64.getDecoder().decode(signature.getBytes("UTF-8")));
32.}
