BAEL-4219 - How to read .pem file to get private and public key (#9676)

2020-07-12 21:03:46 +03:00
parent 1a8969f376
commit ff310e08e6
8 changed files with 267 additions and 0 deletions
@@ -0,0 +1,71 @@
+package com.baeldung.pem;
+
+import org.bouncycastle.asn1.pkcs.PrivateKeyInfo;
+import org.bouncycastle.asn1.x509.SubjectPublicKeyInfo;
+import org.bouncycastle.openssl.PEMParser;
+import org.bouncycastle.openssl.jcajce.JcaPEMKeyConverter;
+import org.bouncycastle.util.io.pem.PemObject;
+import org.bouncycastle.util.io.pem.PemReader;
+
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.security.KeyFactory;
+import java.security.NoSuchAlgorithmException;
+import java.security.interfaces.RSAPrivateKey;
+import java.security.interfaces.RSAPublicKey;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.PKCS8EncodedKeySpec;
+import java.security.spec.X509EncodedKeySpec;
+
+public class BouncyCastlePemUtils {
+
+    public static RSAPublicKey readX509PublicKey(File file) throws InvalidKeySpecException, IOException, NoSuchAlgorithmException {
+        KeyFactory factory = KeyFactory.getInstance("RSA");
+
+        try (FileReader keyReader = new FileReader(file);
+             PemReader pemReader = new PemReader(keyReader)) {
+
+            PemObject pemObject = pemReader.readPemObject();
+            byte[] content = pemObject.getContent();
+            X509EncodedKeySpec pubKeySpec = new X509EncodedKeySpec(content);
+            return (RSAPublicKey) factory.generatePublic(pubKeySpec);
+        }
+    }
+
+    public static RSAPublicKey readX509PublicKeySecondApproach(File file) throws IOException {
+        try (FileReader keyReader = new FileReader(file)) {
+
+            PEMParser pemParser = new PEMParser(keyReader);
+            JcaPEMKeyConverter converter = new JcaPEMKeyConverter();
+            SubjectPublicKeyInfo publicKeyInfo = SubjectPublicKeyInfo.getInstance(pemParser.readObject());
+
+            return (RSAPublicKey) converter.getPublicKey(publicKeyInfo);
+        }
+    }
+
+    public static RSAPrivateKey readPKCS8PrivateKey(File file) throws InvalidKeySpecException, IOException, NoSuchAlgorithmException {
+        KeyFactory factory = KeyFactory.getInstance("RSA");
+
+        try (FileReader keyReader = new FileReader(file);
+             PemReader pemReader = new PemReader(keyReader)) {
+
+            PemObject pemObject = pemReader.readPemObject();
+            byte[] content = pemObject.getContent();
+            PKCS8EncodedKeySpec privKeySpec = new PKCS8EncodedKeySpec(content);
+            return (RSAPrivateKey) factory.generatePrivate(privKeySpec);
+        }
+    }
+
+    public static RSAPrivateKey readPKCS8PrivateKeySecondApproach(File file) throws IOException {
+        try (FileReader keyReader = new FileReader(file)) {
+
+            PEMParser pemParser = new PEMParser(keyReader);
+            JcaPEMKeyConverter converter = new JcaPEMKeyConverter();
+            PrivateKeyInfo privateKeyInfo = PrivateKeyInfo.getInstance(pemParser.readObject());
+
+            return (RSAPrivateKey) converter.getPrivateKey(privateKeyInfo);
+        }
+    }
+
+}