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I'm trying to decrypt and verify a PGP message using the java BouncyCastle libraries, but am running into issues, complaining about premature ends of PartialInputStream.
I know the encrypt works fine, because I can decrypt and verify messages created with the encrypt function using gpg on the command line.
Here's the code:
public static void signEncryptMessage(InputStream in, OutputStream out, PGPPublicKey publicKey, PGPPrivateKey secretKey, SecureRandom rand) throws Exception {
out = new ArmoredOutputStream(out);
PGPEncryptedDataGenerator encryptedDataGenerator = new PGPEncryptedDataGenerator(new BcPGPDataEncryptorBuilder(PGPEncryptedData.AES_256).setWithIntegrityPacket(true).setSecureRandom(rand));
encryptedDataGenerator.addMethod(new BcPublicKeyKeyEncryptionMethodGenerator(publicKey));
OutputStream compressedOut = new PGPCompressedDataGenerator(PGPCompressedData.ZIP).open(encryptedDataGenerator.open(out, 4096), new byte[4096]);
PGPSignatureGenerator signatureGenerator = new PGPSignatureGenerator(new BcPGPContentSignerBuilder(publicKey.getAlgorithm(), HashAlgorithmTags.SHA512));
signatureGenerator.init(PGPSignature.BINARY_DOCUMENT, secretKey);
signatureGenerator.generateOnePassVersion(true).encode(compressedOut);
OutputStream finalOut = new PGPLiteralDataGenerator().open(compressedOut, PGPLiteralData.BINARY, "", new Date(), new byte[4096]);
byte[] buf = new byte[4096];
int len;
while ((len = in.read(buf)) > 0) {
finalOut.write(buf, 0, len);
signatureGenerator.update(buf, 0, len);
}
finalOut.close();
in.close();
signatureGenerator.generate().encode(compressedOut);
compressedOut.close();
encryptedDataGenerator.close();
out.close();
}
public static void decryptVerifyMessage(InputStream in, OutputStream out, PGPPrivateKey secretKey, PGPPublicKey publicKey) throws Exception {
in = new ArmoredInputStream(in);
PGPObjectFactory pgpF = new PGPObjectFactory(in);
PGPEncryptedDataList enc = (PGPEncryptedDataList) pgpF.nextObject();
PGPObjectFactory plainFact = new PGPObjectFactory(((PGPPublicKeyEncryptedData) enc.getEncryptedDataObjects().next()).getDataStream(new JcePublicKeyDataDecryptorFactoryBuilder().setProvider("BC").build(secretKey)));
Object message = null;
PGPOnePassSignatureList onePassSignatureList = null;
PGPSignatureList signatureList = null;
PGPCompressedData compressedData = null;
message = plainFact.nextObject();
ByteArrayOutputStream actualOutput = new ByteArrayOutputStream();
while (message != null) {
System.out.println(message.toString());
if (message instanceof PGPCompressedData) {
compressedData = (PGPCompressedData) message;
plainFact = new PGPObjectFactory(compressedData.getDataStream());
message = plainFact.nextObject();
System.out.println(message.toString());
}
if (message instanceof PGPLiteralData) {
Streams.pipeAll(((PGPLiteralData) message).getInputStream(), actualOutput);
} else if (message instanceof PGPOnePassSignatureList) {
onePassSignatureList = (PGPOnePassSignatureList) message;
} else if (message instanceof PGPSignatureList) {
signatureList = (PGPSignatureList) message;
} else {
throw new PGPException("message unknown message type.");
}
message = plainFact.nextObject();
}
actualOutput.close();
byte[] output = actualOutput.toByteArray();
if (onePassSignatureList == null || signatureList == null) {
throw new PGPException("Poor PGP. Signatures not found.");
} else {
for (int i = 0; i < onePassSignatureList.size(); i++) {
PGPOnePassSignature ops = onePassSignatureList.get(0);
System.out.println("verifier : " + ops.getKeyID());
if (publicKey != null) {
ops.init(new JcaPGPContentVerifierBuilderProvider().setProvider("BC"), publicKey);
ops.update(output);
PGPSignature signature = signatureList.get(i);
if (ops.verify(signature)) {
Iterator<?> userIds = publicKey.getUserIDs();
while (userIds.hasNext()) {
String userId = (String) userIds.next();
System.out.println("Signed by " + userId);
}
System.out.println("Signature verified");
} else {
throw new SignatureException("Signature verification failed");
}
}
}
}
out.write(output);
out.flush();
out.close();
}
public static void main(String args[]) {
Security.insertProviderAt(new BouncyCastleProvider(), 0);
byte inBytes[] = "The quick brown fox jumps over the lazy dog.".getBytes();
try {
SecureRandom rand = new SecureRandom();
RSAKeyPairGenerator kpg = new RSAKeyPairGenerator();
kpg.init(new RSAKeyGenerationParameters(BigInteger.valueOf(0x10001), rand, 1024, 90));
BcPGPKeyPair sender = new BcPGPKeyPair(PGPPublicKey.RSA_GENERAL, kpg.generateKeyPair(), new Date());
BcPGPKeyPair recip = new BcPGPKeyPair(PGPPublicKey.RSA_GENERAL, kpg.generateKeyPair(), new Date());
ByteArrayOutputStream sendMessage = new ByteArrayOutputStream();
ByteArrayOutputStream recvMessage = new ByteArrayOutputStream();
signEncryptMessage(new ByteArrayInputStream(inBytes), sendMessage, recip.getPublicKey(), sender.getPrivateKey(), rand);
System.out.println(sendMessage.toString());
decryptVerifyMessage(new ByteArrayInputStream(sendMessage.toByteArray()), recvMessage, recip.getPrivateKey(), sender.getPublicKey());
System.out.println(recvMessage.toString());
} catch (Exception e) {
e.printStackTrace();
}
}
After a few runs of message = plainFact.nextObject(); the exception is thrown:
-----BEGIN PGP MESSAGE-----
Version: BCPG v1.49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=ApMf
-----END PGP MESSAGE-----
org.bouncycastle.openpgp.PGPCompressedData@cd36a6d
org.bouncycastle.openpgp.PGPOnePassSignatureList@7e224235
org.bouncycastle.openpgp.PGPLiteralData@7b28e644
java.io.EOFException: premature end of stream in PartialInputStream
at org.bouncycastle.bcpg.BCPGInputStream$PartialInputStream.read(Unknown Source)
at org.bouncycastle.bcpg.BCPGInputStream.read(Unknown Source)
at java.io.InputStream.read(InputStream.java:101)
at javax.crypto.CipherInputStream.getMoreData(CipherInputStream.java:103)
at javax.crypto.CipherInputStream.read(CipherInputStream.java:177)
at org.bouncycastle.bcpg.BCPGInputStream.read(Unknown Source)
at org.bouncycastle.openpgp.PGPEncryptedData$TruncatedStream.read(Unknown Source)
at java.io.InputStream.read(InputStream.java:170)
at org.bouncycastle.util.io.TeeInputStream.read(Unknown Source)
at org.bouncycastle.bcpg.BCPGInputStream.read(Unknown Source)
at org.bouncycastle.bcpg.BCPGInputStream$PartialInputStream.read(Unknown Source)
at org.bouncycastle.bcpg.BCPGInputStream.read(Unknown Source)
at org.bouncycastle.openpgp.PGPCompressedData$1.fill(Unknown Source)
at java.util.zip.InflaterInputStream.read(InflaterInputStream.java:158)
at org.bouncycastle.bcpg.BCPGInputStream.read(Unknown Source)
at org.bouncycastle.bcpg.BCPGInputStream$PartialInputStream.read(Unknown Source)
at org.bouncycastle.bcpg.BCPGInputStream.read(Unknown Source)
at org.bouncycastle.util.io.Streams.readFully(Unknown Source)
at org.bouncycastle.bcpg.BCPGInputStream.readFully(Unknown Source)
at org.bouncycastle.bcpg.BCPGInputStream.readFully(Unknown Source)
at org.bouncycastle.bcpg.MPInteger.<init>(Unknown Source)
at org.bouncycastle.bcpg.SignaturePacket.<init>(Unknown Source)
at org.bouncycastle.bcpg.BCPGInputStream.readPacket(Unknown Source)
at org.bouncycastle.openpgp.PGPSignature.<init>(Unknown Source)
at org.bouncycastle.openpgp.PGPObjectFactory.nextObject(Unknown Source)
at main.decryptVerifyMessage(main.java:113)
at main.main(main.java:167)
Any ideas?
Side note, this decryption code came from How to decrypt a signed pgp encrypted file?, slightly modified to suit: Messages will only be coming from that encryption method, and handling of the keys directly instead of key streams.
Cheers
Ramo
555
Getting Bouncy Castle to play along is not always easy. Code-snipets from Stackoverflow make it work just so, but they are mostly arcane pieces of code that none of the users really understand.
The problem with this is: In a production system copy'n'paste snippets quickly become "no go" and "do not touch" areas.
Shelling out executables can have some serious security implications, least of all is handling command line parameters (talking about filenames with spaces ... how do I know? Don't ask ...)
I had all of these (and more..) problems, and after some yak shaving I wrote a library to handle PGP with Bouncycastle.
Decrypting works like this:
final InputStream plaintextStream = BouncyGPG
.decryptAndVerifyStream()
.withConfig(keyringConfig)
.andRequireSignatureFromAllKeys("[email protected]")
.fromEncryptedInputStream(cipherTextStream)
The library can be found at https://github.com/neuhalje/bouncy-gpg :
// in build.gradle add a dependency to bouncy castle and bouncy-gpg
// ...
dependencies {
compile 'org.bouncycastle:bcprov-jdk15on:1.56'
compile 'org.bouncycastle:bcpg-jdk15on:1.56'
// ...
compile 'name.neuhalfen.projects.crypto.bouncycastle.openpgp:bouncy-gpg:2.+'
I was recently trying to do the same kind of thing and put together this method based on code I found in the Bouncycastle examples and on tutorials I found on the web. For my purposes, my code has a singleton crypto object that has a public/private key pair. In the example code, you could replace
INSTANCE._secretKeyRingCollection.getSecretKey(pbe.getKeyID());
with your secret key. I've tested this method with a long-lived process that did several tens of encrypt & sign / decrypt & verify actions and didn't get the exception you're seeing.
public static void decryptAndVerify(InputStream in, OutputStream fOut, InputStream publicKeyIn) throws IOException, SignatureException, PGPException {
in = PGPUtil.getDecoderStream(in);
PGPObjectFactory pgpF = new PGPObjectFactory(in);
PGPEncryptedDataList enc;
Object o = pgpF.nextObject();
//
// the first object might be a PGP marker packet.
//
if (o instanceof PGPEncryptedDataList) {
enc = (PGPEncryptedDataList) o;
} else {
enc = (PGPEncryptedDataList) pgpF.nextObject();
}
//
// find the secret key
//
Iterator<PGPPublicKeyEncryptedData> it = enc.getEncryptedDataObjects();
PGPPrivateKey sKey = null;
PGPPublicKeyEncryptedData pbe = null;
while (sKey == null && it.hasNext()) {
pbe = it.next();
PBESecretKeyDecryptor decryptor = new BcPBESecretKeyDecryptorBuilder(new BcPGPDigestCalculatorProvider()).build(INSTANCE._secretKeyPass.toCharArray());
PGPSecretKey psKey = INSTANCE._secretKeyRingCollection.getSecretKey(pbe.getKeyID());
if (psKey != null) {
sKey = psKey.extractPrivateKey(decryptor);
}
}
if (sKey == null) {
throw new IllegalArgumentException("Unable to find secret key to decrypt the message");
}
InputStream clear = pbe.getDataStream(new BcPublicKeyDataDecryptorFactory(sKey));
PGPObjectFactory plainFact = new PGPObjectFactory(clear);
Object message;
PGPOnePassSignatureList onePassSignatureList = null;
PGPSignatureList signatureList = null;
PGPCompressedData compressedData;
message = plainFact.nextObject();
ByteArrayOutputStream actualOutput = new ByteArrayOutputStream();
while (message != null) {
__l.trace(message.toString());
if (message instanceof PGPCompressedData) {
compressedData = (PGPCompressedData) message;
plainFact = new PGPObjectFactory(compressedData.getDataStream());
message = plainFact.nextObject();
}
if (message instanceof PGPLiteralData) {
// have to read it and keep it somewhere.
Streams.pipeAll(((PGPLiteralData) message).getInputStream(), actualOutput);
} else if (message instanceof PGPOnePassSignatureList) {
onePassSignatureList = (PGPOnePassSignatureList) message;
} else if (message instanceof PGPSignatureList) {
signatureList = (PGPSignatureList) message;
} else {
throw new PGPException("message unknown message type.");
}
message = plainFact.nextObject();
}
actualOutput.close();
PGPPublicKey publicKey = null;
byte[] output = actualOutput.toByteArray();
if (onePassSignatureList == null || signatureList == null) {
throw new PGPException("Poor PGP. Signatures not found.");
} else {
for (int i = 0; i < onePassSignatureList.size(); i++) {
PGPOnePassSignature ops = onePassSignatureList.get(0);
__l.trace("verifier : " + ops.getKeyID());
PGPPublicKeyRingCollection pgpRing = new PGPPublicKeyRingCollection(
PGPUtil.getDecoderStream(publicKeyIn));
publicKey = pgpRing.getPublicKey(ops.getKeyID());
if (publicKey != null) {
ops.init(new JcaPGPContentVerifierBuilderProvider().setProvider("BC"), publicKey);
ops.update(output);
PGPSignature signature = signatureList.get(i);
if (ops.verify(signature)) {
Iterator<?> userIds = publicKey.getUserIDs();
while (userIds.hasNext()) {
String userId = (String) userIds.next();
__l.trace(String.format("Signed by {%s}", userId));
}
__l.trace("Signature verified");
} else {
throw new SignatureException("Signature verification failed");
}
}
}
}
if (pbe.isIntegrityProtected() && !pbe.verify()) {
throw new PGPException("Data is integrity protected but integrity is lost.");
} else if (publicKey == null) {
throw new SignatureException("Signature not found");
} else {
fOut.write(output);
fOut.flush();
fOut.close();
}
}
You are calling:
encryptedDataGenerator.open(out, 4096)
where you probably meant:
encryptedDataGenerator.open(out, new byte[4096])
The first version is giving a size to open (which is wrong), the second version is giving a byte buffer.
(I know this is old, but came here because I had the same problem with some example code and so might others)
2
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