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Add documentation for the DecryptOrVerify examples

This commit is contained in:
Paul Schaub 2022-03-16 21:29:34 +01:00
parent 2dba981e07
commit 9e0aa95a5a
Signed by: vanitasvitae
GPG key ID: 62BEE9264BF17311

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@ -30,8 +30,14 @@ import org.pgpainless.encryption_signing.ProducerOptions;
import org.pgpainless.encryption_signing.SigningOptions;
import org.pgpainless.key.protection.SecretKeyRingProtector;
/**
* This class contains examples on how to decrypt encrypted, and verify signed messages.
*/
public class DecryptOrVerify {
/**
* The secret key.
*/
private static final String KEY = "-----BEGIN PGP PRIVATE KEY BLOCK-----\n" +
"Version: PGPainless\n" +
"Comment: AA21 9149 3B35 E679 8876 DE43 B0D7 8185 F639 B6C9\n" +
@ -56,11 +62,22 @@ public class DecryptOrVerify {
"=JHMt\n" +
"-----END PGP PRIVATE KEY BLOCK-----\n";
// The key above is not password protected.
/**
* Protector to unlock the secret key.
* Since the key is not protected, it is enough to use an unprotectedKeys implementation.
*
* For more info on how to use the {@link SecretKeyRingProtector}, see {@link UnlockSecretKeys}.
*/
private static final SecretKeyRingProtector keyProtector = SecretKeyRingProtector.unprotectedKeys();
/**
* The plaintext message.
*/
private static final String PLAINTEXT = "Hello, World!\n";
/**
* The {@link #PLAINTEXT} message, but signed using inband signatures.
*/
private static final String INBAND_SIGNED = "-----BEGIN PGP MESSAGE-----\n" +
"Version: PGPainless\n" +
"\n" +
@ -70,6 +87,10 @@ public class DecryptOrVerify {
"M8e7ufwA\n" +
"=RDiy\n" +
"-----END PGP MESSAGE-----";
/**
* The {@link #PLAINTEXT} message, but signed using the cleartext signature framework.
*/
private static final String CLEARTEXT_SIGNED = "-----BEGIN PGP SIGNED MESSAGE-----\n" +
"Hash: SHA512\n" +
"\n" +
@ -83,6 +104,10 @@ public class DecryptOrVerify {
"QUibivG5Slahz8l7PWnGkxbB2naQxgw=\n" +
"=oNIK\n" +
"-----END PGP SIGNATURE-----";
/**
* The {@link #PLAINTEXT} message, but encrypted for the {@link #certificate}.
*/
private static final String ENCRYPTED = "-----BEGIN PGP MESSAGE-----\n" +
"Version: PGPainless\n" +
"\n" +
@ -92,6 +117,10 @@ public class DecryptOrVerify {
"/lWeVnK7NwtfArlhpRcph0S8\n" +
"=1cyl\n" +
"-----END PGP MESSAGE-----\n";
/**
* The {@link #PLAINTEXT} message signed by the {@link #secretKey} and encrypted for the {@link #certificate}.
*/
private static final String ENCRYPTED_AND_SIGNED = "-----BEGIN PGP MESSAGE-----\n" +
"Version: PGPainless\n" +
"\n" +
@ -110,37 +139,55 @@ public class DecryptOrVerify {
@BeforeAll
public static void prepare() throws IOException {
// read the secret key
secretKey = PGPainless.readKeyRing().secretKeyRing(KEY);
// certificate is the public part of the key
certificate = PGPainless.extractCertificate(secretKey);
}
/**
* This example demonstrates how to decrypt an encrypted message using a secret key.
*
* @throws PGPException
* @throws IOException
*/
@Test
public void decryptMessage() throws PGPException, IOException {
ConsumerOptions consumerOptions = new ConsumerOptions()
.addDecryptionKey(secretKey, keyProtector);
.addDecryptionKey(secretKey, keyProtector); // add the decryption key ring
ByteArrayOutputStream plaintextOut = new ByteArrayOutputStream();
ByteArrayInputStream ciphertextIn = new ByteArrayInputStream(ENCRYPTED.getBytes(StandardCharsets.UTF_8));
// The decryption stream is an input stream from which we read the decrypted data
DecryptionStream decryptionStream = PGPainless.decryptAndOrVerify()
.onInputStream(ciphertextIn)
.withOptions(consumerOptions);
Streams.pipeAll(decryptionStream, plaintextOut);
decryptionStream.close();
decryptionStream.close(); // remember to close the stream!
// The metadata object contains information about the message
OpenPgpMetadata metadata = decryptionStream.getResult();
assertTrue(metadata.isEncrypted()); // message was encrypted
assertFalse(metadata.isVerified()); // We did not do any signature verification
// The output stream now contains the decrypted message
assertEquals(PLAINTEXT, plaintextOut.toString());
}
/**
* In this example, an encrypted and signed message is processed.
* The message gets decrypted using the secret key and the signatures are verified using the certificate.
*
* @throws PGPException
* @throws IOException
*/
@Test
public void decryptMessageAndVerifySignatures() throws PGPException, IOException {
ConsumerOptions consumerOptions = new ConsumerOptions()
.addDecryptionKey(secretKey, keyProtector)
.addVerificationCert(certificate);
.addDecryptionKey(secretKey, keyProtector) // provide the secret key of the recipient for decryption
.addVerificationCert(certificate); // provide the signers public key for signature verification
ByteArrayOutputStream plaintextOut = new ByteArrayOutputStream();
ByteArrayInputStream ciphertextIn = new ByteArrayInputStream(ENCRYPTED_AND_SIGNED.getBytes(StandardCharsets.UTF_8));
@ -150,66 +197,98 @@ public class DecryptOrVerify {
.withOptions(consumerOptions);
Streams.pipeAll(decryptionStream, plaintextOut);
decryptionStream.close();
decryptionStream.close(); // remember to close the stream to finish signature verification
// metadata with information on the message, like signatures
OpenPgpMetadata metadata = decryptionStream.getResult();
assertTrue(metadata.isEncrypted());
assertTrue(metadata.isSigned());
assertTrue(metadata.isVerified());
assertTrue(metadata.containsVerifiedSignatureFrom(certificate));
assertTrue(metadata.isEncrypted()); // messages was in fact encrypted
assertTrue(metadata.isSigned()); // message contained some signatures
assertTrue(metadata.isVerified()); // the signatures were actually correct
assertTrue(metadata.containsVerifiedSignatureFrom(certificate)); // the signatures could be verified using the certificate
assertEquals(PLAINTEXT, plaintextOut.toString());
}
/**
* In this example, signed messages are verified.
* The example shows that verification of inband signed, and cleartext signed messages works the same.
* @throws PGPException
* @throws IOException
*/
@Test
public void verifySignatures() throws PGPException, IOException {
ConsumerOptions options = new ConsumerOptions()
.addVerificationCert(certificate);
.addVerificationCert(certificate); // provide the signers certificate for verification of signatures
for (String signed : new String[] {INBAND_SIGNED, CLEARTEXT_SIGNED}) {
ByteArrayOutputStream out = new ByteArrayOutputStream();
ByteArrayInputStream in = new ByteArrayInputStream(signed.getBytes(StandardCharsets.UTF_8));
DecryptionStream verificationStream;
verificationStream = PGPainless.decryptAndOrVerify()
.onInputStream(in)
.withOptions(options);
DecryptionStream verificationStream = PGPainless.decryptAndOrVerify()
.onInputStream(in)
.withOptions(options);
Streams.pipeAll(verificationStream, out);
verificationStream.close();
verificationStream.close(); // remember to close the stream to finish sig verification
// Get the metadata object for information about the message
OpenPgpMetadata metadata = verificationStream.getResult();
assertTrue(metadata.isVerified());
assertTrue(metadata.isVerified()); // signatures were verified successfully
// The output stream we piped to now contains the message
assertEquals(PLAINTEXT, out.toString());
}
}
/**
* This example shows how to create - and verify - cleartext signed messages.
* @throws PGPException
* @throws IOException
*/
@Test
public void createVerifyCleartextSignedMessage() throws PGPException, IOException {
public void createAndVerifyCleartextSignedMessage() throws PGPException, IOException {
// In this example we sign and verify a number of different messages one after the other
for (String msg : new String[] {"Hello World!", "- Hello - World -", "Hello, World!\n", "Hello\nWorld!"}) {
// we need to read the plaintext message from somewhere
ByteArrayInputStream in = new ByteArrayInputStream(msg.getBytes(StandardCharsets.UTF_8));
// and write the signed message to an output stream
ByteArrayOutputStream out = new ByteArrayOutputStream();
SigningOptions signingOptions = SigningOptions.get();
// for cleartext signed messages, we need to add a detached signature...
signingOptions.addDetachedSignature(keyProtector, secretKey, DocumentSignatureType.CANONICAL_TEXT_DOCUMENT);
ProducerOptions producerOptions = ProducerOptions.sign(signingOptions)
.setCleartextSigned(); // and declare that the message will be cleartext signed
// Create the signing stream
EncryptionStream signingStream = PGPainless.encryptAndOrSign()
.onOutputStream(out)
.withOptions(ProducerOptions.sign(SigningOptions.get()
.addDetachedSignature(SecretKeyRingProtector.unprotectedKeys(), secretKey, DocumentSignatureType.CANONICAL_TEXT_DOCUMENT)
).setCleartextSigned());
.onOutputStream(out) // on the output stream
.withOptions(producerOptions); // with the options
Streams.pipeAll(in, signingStream);
signingStream.close();
Streams.pipeAll(in, signingStream); // pipe the plaintext message into the signing stream
signingStream.close(); // remember to close the stream to finish the signatures
ByteArrayInputStream signedIn = new ByteArrayInputStream(out.toByteArray());
// Now the output stream contains the signed message
byte[] signedMessage = out.toByteArray();
// Verification
// we need to read the signed message
ByteArrayInputStream signedIn = new ByteArrayInputStream(signedMessage);
// and pass it to the decryption stream
DecryptionStream verificationStream = PGPainless.decryptAndOrVerify()
.onInputStream(signedIn)
.withOptions(new ConsumerOptions().addVerificationCert(certificate));
// plain will receive the plaintext message
ByteArrayOutputStream plain = new ByteArrayOutputStream();
Streams.pipeAll(verificationStream, plain);
verificationStream.close();
verificationStream.close(); // as always, remember to close the stream
// Metadata will confirm that the message was in fact signed
OpenPgpMetadata metadata = verificationStream.getResult();
assertTrue(metadata.isVerified());
// compare the plaintext to what we originally signed
assertArrayEquals(msg.getBytes(StandardCharsets.UTF_8), plain.toByteArray());
}
}