How to do PGP encryption in Java?

In order to do PGP encryption, you need the PGP public key file. In this post I will tell how to encrypt data with PGP public key in Java. Dependencies Welcome to the home of the Legion of the Bouncy Castle. A fun place to stay, if you've got some time to kill. bouncycastle.orgHome of open source libraries of the Legion of the Bouncy Castle and their Java cryptography and C# cryptography resources https://mvnrepository.com/artifact/org.bouncycastle/bcprov-jdk15on/1.70 The Bouncy Castle Cry

Post, Code and Quiet Time. How to do PGP encryption in Java? By Errong Leng – 22 Apr 2023 – View online → Photo by Allec Gomes / Unsplash In order to do PGP encryption, you need the PGP public key file. In this post I will tell how to encrypt data with PGP public key in Java. Dependencies Welcome to the home of the Legion of the Bouncy Castle. A fun place to stay, if you've got some time to kill. bouncycastle.org Home of open source libraries of the Legion of the Bouncy Castle and their Java cryptography and C# cryptography resources https://mvnrepository.com/artifact/org.bouncycastle/bcprov-jdk15on/1.70 The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5 and up. https://mvnrepository.com/artifact/org.bouncycastle/bcpkix-jdk15on/1.70 The Bouncy Castle Java APIs for CMS, PKCS, EAC, TSP, CMP, CRMF, OCSP, and certificate generation. This jar contains APIs for JDK 1.5 and up. The APIs can be used in conjunction with a JCE/JCA provider such as the one provided with the Bouncy Castle Cryptography APIs. Read PGPPublicKey from file Now we have The Bouncy Castle Java APIs, let's try to load the PGP public file into PGPPublicKey object. The main idea is iterator the keys in the ring collection and find the key isEncryptionKey. import java.io.FileInputStream; import java.io.IOException; import java.util.Iterator; import lombok.val; import org.bouncycastle.openpgp.PGPException; import org.bouncycastle.openpgp.PGPUtil; import org.bouncycastle.openpgp.PGPPublicKey; import org.bouncycastle.openpgp.PGPPublicKeyRing; import org.bouncycastle.openpgp.PGPPublicKeyRingCollection; import org.bouncycastle.openpgp.operator.bc.BcKeyFingerprintCalculator; public class PGPHelper { PGPPublicKey readPublicKey(String publicKeyFilePath) throws IOException, PGPException { val in = PGPUtil.getDecoderStream(new FileInputStream(publicKeyFilePath)); PGPPublicKeyRingCollection pgpPub = new PGPPublicKeyRingCollection(in, new BcKeyFingerprintCalculator()); PGPPublicKey key = null; Iterator rIt = pgpPub.getKeyRings(); while (key == null && rIt.hasNext()) { PGPPublicKeyRing kRing = (PGPPublicKeyRing) rIt.next(); Iterator kIt = kRing.getPublicKeys(); while (key == null && kIt.hasNext()) { PGPPublicKey k = (PGPPublicKey) kIt.next(); if (k.isEncryptionKey()) { key = k; } } } if (key == null) { throw new IllegalArgumentException("Can't find encryption key in key ring."); } return key; } } view raw PGPHelper.java hosted with ❤ by GitHub Encrypt Data import java.io.ByteArrayOutputStream; import java.io.FileInputStream; import java.io.IOException; import java.io.OutputStream; import java.util.Date; import java.util.Iterator; import lombok.val; import org.bouncycastle.bcpg.SymmetricKeyAlgorithmTags; import org.bouncycastle.openpgp.PGPEncryptedDataGenerator; import org.bouncycastle.openpgp.PGPException; import org.bouncycastle.openpgp.PGPLiteralData; import org.bouncycastle.openpgp.PGPLiteralDataGenerator; import org.bouncycastle.openpgp.PGPUtil; import org.bouncycastle.openpgp.PGPPublicKey; import org.bouncycastle.openpgp.PGPPublicKeyRing; import org.bouncycastle.openpgp.PGPPublicKeyRingCollection; import org.bouncycastle.openpgp.operator.bc.BcKeyFingerprintCalculator; import org.bouncycastle.openpgp.operator.bc.BcPGPDataEncryptorBuilder; import org.bouncycastle.openpgp.operator.bc.BcPublicKeyKeyEncryptionMethodGenerator; public class PGPHelper { public byte[] encrypt(byte[] data, PGPPublicKey pgpPublicKey) { try { PGPEncryptedDataGenerator encGen = new PGPEncryptedDataGenerator( new BcPGPDataEncryptorBuilder(SymmetricKeyAlgorithmTags.AES_256) .setWithIntegrityPacket(true)); encGen.addMethod(new BcPublicKeyKeyEncryptionMethodGenerator(pgpPublicKey)); ByteArrayOutputStream out = new ByteArrayOutputStream(); // create an indefinite length encrypted stream OutputStream cOut = encGen.open(out, new byte[4096]); // write out the literal data PGPLiteralDataGenerator lData = new PGPLiteralDataGenerator(); OutputStream pOut = lData.open( cOut, PGPLiteralData.BINARY, PGPLiteralData.CONSOLE, data.length, new Date()); pOut.write(data); pOut.close(); cOut.close(); return out.toByteArray(); } catch (Exception e) { throw new RuntimeException(e.getCause()); } } PGPPublicKey readPublicKey(String publicKeyFilePath) throws IOException, PGPException { val in = PGPUtil.getDecoderStream(new FileInputStream(publicKeyFilePath)); PGPPublicKeyRingCollection pgpPub = new PGPPublicKeyRingCollection(in, new BcKeyFingerprintCalculator()); PGPPublicKey key = null; Iterator rIt = pgpPub.getKeyRings(); while (key == null && rIt.hasNext()) { PGPPublicKeyRing kRing = (PGPPublicKeyRing) rIt.next(); Iterator kIt = kRing.getPublicKeys(); while (key == null && kIt.hasNext()) { PGPPublicKey k = (PGPPublicKey) kIt.next(); if (k.isEncryptionKey()) { key = k; } } } if (key == null) { throw new IllegalArgumentException("Can't find encryption key in key ring."); } return key; } } view raw PGPEncrypt.java hosted with ❤ by GitHub Key points: PGPEncryptedDataGenerator::addMethod(new BcPublicKeyKeyEncryptionMethodGenerator(pgpPublicKey)); PGPLiteralDataGenerator::open That is it. Hope you find it helps. I will write another post for PGP decryption. Post, Code and Quiet Time. © 2023 – Unsubscribe