検証署名のテスト

digest

acd7be03019c5b0791efed326c77937cc72b82ab0f4ce152b9beb8c8595d2a13

signature

3044022078351d9817d3f4f449a7ebeeab8f1be11513c89a0e25d71828e7ff6cab25000d02201836ca3f071a7ea66a84a398763db0c9426bff38adc57d423b8b11b6219c38a8

maven dependency

     org.bouncycastle
     bcprov-jdk15on
     1.60


     commons-io
     commons-io
     2.6

public class ECSDASign {

    static {
        try {
            Security.addProvider(new BouncyCastleProvider());
        } catch(Exception e) {
            e.printStackTrace();
        }
    }
    
    public static void main(String[] args) throws Exception {
        PublicKey pubk = getPemPublicKey("/Users/zhouchunchen/Desktop/pub.pem","EC");

        byte digest[] = Hex.decode("acd7be03019c5b0791efed326c77937cc72b82ab0f4ce152b9beb8c8595d2a13");
        byte signature[] =  Hex.decode("3044022078351d9817d3f4f449a7ebeeab8f1be11513c89a0e25d71828e7ff6cab25000d02201836ca3f071a7ea66a84a398763db0c9426bff38adc57d423b8b11b6219c38a8");
        
        verify(digest, signature, pubk);
    }
    
    public static PublicKey getPemPublicKey(String filename, String algorithm) throws Exception {
        String b64pk = FileUtils.readFileToString(new File(filename), "UTF-8");

        b64pk = b64pk.replace("-----BEGIN PUBLIC KEY-----
", "");
        b64pk = b64pk.replace("-----END PUBLIC KEY-----", "");

        Base64 b64 = new Base64();
        byte [] decoded = b64.decode(b64pk);

        X509EncodedKeySpec spec = new X509EncodedKeySpec(decoded);
        KeyFactory kf = KeyFactory.getInstance(algorithm);
        return kf.generatePublic(spec);
    }

    private static void verify(byte[] digest, byte[] signature, PublicKey publicKey )
            throws NoSuchAlgorithmException, InvalidKeyException, SignatureException, UnsupportedEncodingException, NoSuchProviderException {
        final Signature sig = Signature.getInstance("SHA256withECDSA", "BC");
        sig.initVerify( publicKey );
        sig.update(digest);
        System.out.println(sig.verify( signature ));
    }
}