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Merge branch 'sessionKeyDecryption' of https://github.com/pgpainless/bc-java into pgpainless-sessionKeyDecryption
2 parents f4ee6b4 + fa70560 commit f42a2e8

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‎pg/src/main/java/org/bouncycastle/openpgp/PGPEncryptedDataList.java‎

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@@ -14,6 +14,7 @@
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import org.bouncycastle.bcpg.Packet;
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import org.bouncycastle.bcpg.PacketTags;
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import org.bouncycastle.bcpg.PublicKeyEncSessionPacket;
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import org.bouncycastle.bcpg.SymmetricEncIntegrityPacket;
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import org.bouncycastle.bcpg.SymmetricKeyEncSessionPacket;
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import org.bouncycastle.bcpg.UnsupportedPacketVersionException;
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import org.bouncycastle.util.Iterable;
@@ -128,6 +129,30 @@ public PGPEncryptedDataList(
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}
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}
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/**
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* Add a decryption method using a {@link PGPSessionKey}.
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* This method can be used to decrypt messages which do not contain a SKESK or PKESK packet using a
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* session key.
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*
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* @param sessionKey session key for message decryption
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* @return session key encrypted data
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*/
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public PGPSessionKeyEncryptedData addSessionKeyDecryptionMethod(PGPSessionKey sessionKey)
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{
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PGPSessionKeyEncryptedData sessionKeyEncryptedData = new PGPSessionKeyEncryptedData(sessionKey, data);
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methods.add(sessionKeyEncryptedData);
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return sessionKeyEncryptedData;
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}
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/** Checks whether the packet is integrity protected.
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*
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* @return <code>true</code> if there is a modification detection code package associated with
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* this stream
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*/
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public boolean isIntegrityProtected() {
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return data instanceof SymmetricEncIntegrityPacket;
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}
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/**
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* Gets the encryption method object at the specified index.
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*

‎pg/src/main/java/org/bouncycastle/openpgp/PGPObjectFactory.java‎

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@@ -135,6 +135,9 @@ public Object nextObject()
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return new PGPLiteralData(in);
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case PacketTags.PUBLIC_KEY_ENC_SESSION:
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case PacketTags.SYMMETRIC_KEY_ENC_SESSION:
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case PacketTags.SYMMETRIC_KEY_ENC:
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case PacketTags.SYM_ENC_INTEGRITY_PRO:
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case PacketTags.AEAD_ENC_DATA:
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return new PGPEncryptedDataList(in);
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case PacketTags.ONE_PASS_SIGNATURE:
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l = new ArrayList();

‎pg/src/main/java/org/bouncycastle/openpgp/PGPSessionKeyEncryptedData.java‎

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@@ -0,0 +1,144 @@
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package org.bouncycastle.openpgp;
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import org.bouncycastle.bcpg.AEADEncDataPacket;
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import org.bouncycastle.bcpg.BCPGInputStream;
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import org.bouncycastle.bcpg.InputStreamPacket;
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import org.bouncycastle.bcpg.SymmetricEncIntegrityPacket;
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import org.bouncycastle.openpgp.operator.PGPDataDecryptor;
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import org.bouncycastle.openpgp.operator.SessionKeyDataDecryptorFactory;
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import org.bouncycastle.util.io.TeeInputStream;
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import java.io.EOFException;
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import java.io.InputStream;
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public class PGPSessionKeyEncryptedData extends PGPEncryptedData
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{
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private final PGPSessionKey sessionKey;
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PGPSessionKeyEncryptedData(PGPSessionKey sessionKey, InputStreamPacket encData)
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{
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super(encData);
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this.sessionKey = sessionKey;
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}
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public PGPSessionKey getSessionKey()
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{
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return sessionKey;
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}
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public InputStream getDataStream(
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SessionKeyDataDecryptorFactory dataDecryptorFactory)
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throws PGPException
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{
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if (encData instanceof AEADEncDataPacket)
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{
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AEADEncDataPacket aeadData = (AEADEncDataPacket) encData;
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if (aeadData.getAlgorithm() != getAlgorithm())
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{
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throw new PGPException("session key and AEAD algorithm mismatch");
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}
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PGPDataDecryptor dataDecryptor = dataDecryptorFactory.createDataDecryptor(aeadData.getAEADAlgorithm(), aeadData.getIV(), aeadData.getChunkSize(), sessionKey.getAlgorithm(), sessionKey.getKey());
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BCPGInputStream encIn = encData.getInputStream();
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return new BCPGInputStream(dataDecryptor.getInputStream(encIn));
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}
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else
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{
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try
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{
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boolean withIntegrityPacket = encData instanceof SymmetricEncIntegrityPacket;
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PGPDataDecryptor dataDecryptor = dataDecryptorFactory.createDataDecryptor(withIntegrityPacket, sessionKey.getAlgorithm(), sessionKey.getKey());
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return getDataStream(withIntegrityPacket, dataDecryptor);
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} catch (PGPException e)
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{
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throw e;
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} catch (Exception e)
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{
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throw new PGPException("Exception creating cipher", e);
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}
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}
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}
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private InputStream getDataStream(
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boolean withIntegrityPacket,
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PGPDataDecryptor dataDecryptor)
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throws PGPException
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{
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try
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{
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BCPGInputStream encIn = encData.getInputStream();
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encIn.mark(dataDecryptor.getBlockSize() + 2); // iv + 2 octets checksum
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encStream = new BCPGInputStream(dataDecryptor.getInputStream(encIn));
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if (withIntegrityPacket)
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{
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truncStream = new TruncatedStream(encStream);
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integrityCalculator = dataDecryptor.getIntegrityCalculator();
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encStream = new TeeInputStream(truncStream, integrityCalculator.getOutputStream());
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}
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byte[] iv = new byte[dataDecryptor.getBlockSize()];
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for (int i = 0; i != iv.length; i++)
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{
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int ch = encStream.read();
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if (ch < 0)
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{
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throw new EOFException("unexpected end of stream.");
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}
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iv[i] = (byte)ch;
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}
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int v1 = encStream.read();
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int v2 = encStream.read();
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if (v1 < 0 || v2 < 0)
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{
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throw new EOFException("unexpected end of stream.");
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}
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// Note: the oracle attack on "quick check" bytes is not deemed
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// a security risk for PBE (see PGPPublicKeyEncryptedData)
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boolean repeatCheckPassed = iv[iv.length - 2] == (byte)v1
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&& iv[iv.length - 1] == (byte)v2;
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// Note: some versions of PGP appear to produce 0 for the extra
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// bytes rather than repeating the two previous bytes
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boolean zeroesCheckPassed = v1 == 0 && v2 == 0;
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if (!repeatCheckPassed && !zeroesCheckPassed)
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{
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encIn.reset();
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throw new PGPDataValidationException("data check failed.");
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}
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return encStream;
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}
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catch (PGPException e)
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{
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throw e;
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}
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catch (Exception e)
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{
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throw new PGPException("Exception creating cipher", e);
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}
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}
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@Override
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public int getAlgorithm()
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{
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return sessionKey.getAlgorithm();
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}
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}

‎pg/src/test/java/org/bouncycastle/openpgp/test/PGPSessionKeyTest.java‎

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@@ -21,6 +21,7 @@
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import org.bouncycastle.openpgp.PGPSecretKey;
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import org.bouncycastle.openpgp.PGPSecretKeyRing;
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import org.bouncycastle.openpgp.PGPSessionKey;
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import org.bouncycastle.openpgp.PGPSessionKeyEncryptedData;
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import org.bouncycastle.openpgp.bc.BcPGPObjectFactory;
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import org.bouncycastle.openpgp.operator.PBEDataDecryptorFactory;
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import org.bouncycastle.openpgp.operator.PBESecretKeyDecryptor;
@@ -110,6 +111,8 @@ public void performTest()
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verifyJcePBEDecryptorFactoryFromSessionKeyCanDecryptDataSuccessfully();
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testSessionKeyFromString();
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decryptMessageWithoutEskUsingSessionKey();
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}
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private void verifyPublicKeyDecryptionYieldsCorrectSessionData()
@@ -264,4 +267,46 @@ private void testSessionKeyFromString()
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isEquals("FCA4BEAF687F48059CACC14FB019125CD57392BAB7037C707835925CBF9F7BCD", Hex.toHexString(sessionKey.getKey()).toUpperCase());
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//isEquals(sessionKeyString, sessionKey.toString());
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}
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// Message consisting only of a symmetrically encrypted integrity protected data packet wrapping a literal data packet
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// see https://dump.sequoia-pgp.org/?data=-----BEGIN%20PGP%20MESSAGE-----%0D%0AVersion%3A%20PGPainless%0D%0A%0D%0A0j8BNtJwO2PLoRdG%2BVynivV7XpHp2Nw/S489vksUKct67CYTFpVTzB4IcJwmUGMm%0D%0Are/N1KMTznEBzy3Txa1QVBc%3D%0D%0A%3Dt%2Bpk%0D%0A-----END%20PGP%20MESSAGE-----&session_key=26BE99BC478520FBC8AB8FB84991DACE4B82CFB9B00F7D05C051D69B8CEA8A7F
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private static final String encryptedMessageWithoutESK = "" +
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"-----BEGIN PGP MESSAGE-----\n" +
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"Version: PGPainless\n" +
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"\n" +
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"0j8BNtJwO2PLoRdG+VynivV7XpHp2Nw/S489vksUKct67CYTFpVTzB4IcJwmUGMm\n" +
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"re/N1KMTznEBzy3Txa1QVBc=\n" +
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"=t+pk\n" +
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"-----END PGP MESSAGE-----";
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private static final PGPSessionKey sessionKey = PGPSessionKey.fromAsciiRepresentation(
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"9:26be99bc478520fbc8ab8fb84991dace4b82cfb9b00f7d05c051d69b8cea8a7f");
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private void decryptMessageWithoutEskUsingSessionKey()
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throws IOException, PGPException
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{
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ByteArrayInputStream msgIn = new ByteArrayInputStream(Strings.toByteArray(encryptedMessageWithoutESK));
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ArmoredInputStream armorIn = new ArmoredInputStream(msgIn);
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PGPObjectFactory objectFactory = new BcPGPObjectFactory(armorIn);
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PGPEncryptedDataList encryptedData = (PGPEncryptedDataList) objectFactory.nextObject();
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isEquals(0, encryptedData.size()); // there is no encrypted session key packet
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// Add decryption method using a session key
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PGPSessionKeyEncryptedData sessionKeyEncData = encryptedData.addSessionKeyDecryptionMethod(sessionKey);
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isEquals(1, encryptedData.size());
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SessionKeyDataDecryptorFactory decryptorFactory = new BcSessionKeyDataDecryptorFactory(sessionKey);
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InputStream decrypted = sessionKeyEncData.getDataStream(decryptorFactory);
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objectFactory = new BcPGPObjectFactory(decrypted);
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PGPLiteralData literalData = (PGPLiteralData) objectFactory.nextObject();
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ByteArrayOutputStream out = new ByteArrayOutputStream();
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Streams.pipeAll(literalData.getDataStream(), out);
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literalData.getDataStream().close();
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decrypted.close();
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armorIn.close();
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isTrue(Arrays.equals(Strings.toByteArray("Hello, World!\n"), out.toByteArray()));
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}
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}

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