### Question:
BisqInstaller { public static VerifyStatusEnum verifySignature(File pubKeyFile, File sigFile, File dataFile) throws Exception { InputStream inputStream; int bytesRead; PGPPublicKey publicKey; PGPSignature pgpSignature; boolean result; inputStream = PGPUtil.getDecoderStream(new FileInputStream(pubKeyFile)); PGPPublicKeyRingCollection publicKeyRingCollection = new PGPPublicKeyRingCollection(inputStream, new JcaKeyFingerprintCalculator()); inputStream.close(); Iterator<PGPPublicKeyRing> iterator = publicKeyRingCollection.getKeyRings(); PGPPublicKeyRing pgpPublicKeyRing; if (iterator.hasNext()) { pgpPublicKeyRing = iterator.next(); } else { throw new PGPException("Could not find public keyring in provided key file"); } inputStream = PGPUtil.getDecoderStream(new FileInputStream(sigFile)); PGPObjectFactory pgpObjectFactory = new PGPObjectFactory(inputStream, new JcaKeyFingerprintCalculator()); Object o = pgpObjectFactory.nextObject(); if (o instanceof PGPSignatureList) { PGPSignatureList signatureList = (PGPSignatureList) o; checkArgument(!signatureList.isEmpty(), "signatureList must not be empty"); pgpSignature = signatureList.get(0); } else if (o instanceof PGPSignature) { pgpSignature = (PGPSignature) o; } else { throw new SignatureException("Could not find signature in provided signature file"); } inputStream.close(); log.debug("KeyID used in signature: %X\n", pgpSignature.getKeyID()); publicKey = pgpPublicKeyRing.getPublicKey(pgpSignature.getKeyID()); if (publicKey == null) return VerifyStatusEnum.FAIL; log.debug("The ID of the selected key is %X\n", publicKey.getKeyID()); pgpSignature.init(new BcPGPContentVerifierBuilderProvider(), publicKey); byte[] data = new byte[1024]; inputStream = new DataInputStream(new BufferedInputStream(new FileInputStream(dataFile))); while (true) { bytesRead = inputStream.read(data, 0, 1024); if (bytesRead == -1) break; pgpSignature.update(data, 0, bytesRead); } inputStream.close(); result = pgpSignature.verify(); return result ? VerifyStatusEnum.OK : VerifyStatusEnum.FAIL; }  boolean isSupportedOS(); Optional<DownloadTask> download(String version); VerifyTask verify(List<FileDescriptor> fileDescriptors); static VerifyStatusEnum verifySignature(File pubKeyFile, File sigFile, File dataFile); List<FileDescriptor> getSigFileDescriptors(FileDescriptor installerFileDescriptor, List<FileDescriptor> keys);  }### Answer:
@Test public void verifySignature() throws Exception { URL url = this.getClass().getResource("/downloadUpdate/test.txt"); File dataFile = new File(url.toURI().getPath()); url = this.getClass().getResource("/downloadUpdate/test.txt.asc"); File sigFile = new File(url.toURI().getPath()); url = this.getClass().getResource("/downloadUpdate/F379A1C6.asc"); File pubKeyFile = new File(url.toURI().getPath()); assertEquals(BisqInstaller.VerifyStatusEnum.OK, BisqInstaller.verifySignature(pubKeyFile, sigFile, dataFile)); url = this.getClass().getResource("/downloadUpdate/test_bad.txt"); dataFile = new File(url.toURI().getPath()); url = this.getClass().getResource("/downloadUpdate/test_bad.txt.asc"); sigFile = new File(url.toURI().getPath()); url = this.getClass().getResource("/downloadUpdate/F379A1C6.asc"); pubKeyFile = new File(url.toURI().getPath()); BisqInstaller.verifySignature(pubKeyFile, sigFile, dataFile); assertEquals(BisqInstaller.VerifyStatusEnum.FAIL, BisqInstaller.verifySignature(pubKeyFile, sigFile, dataFile)); }