bug6095: added persistence for AI Core Credentials, using AES encryption with random salt

java/com.sap.sse.aicore/src/com/sap/sse/aicore/CredentialsParser.java

@@ -7,6 +7,7 @@ import java.net.MalformedURLException;
 import org.json.simple.parser.ParseException;
 
 import com.sap.sse.aicore.impl.CredentialsParserImpl;
+import com.sap.sse.common.Util.Pair;
 
 public interface CredentialsParser {
     static CredentialsParser create() {
@@ -16,4 +17,17 @@ public interface CredentialsParser {
     Credentials parse(Reader r) throws IOException, ParseException;
     
     Credentials parse(CharSequence s) throws ParseException, MalformedURLException;
+
+    /**
+     * @return a pair of which the {@link Pair#getA() first} component represents the encoded credentials, using a
+     *         random "salt" returned as the {@link Pair#getB() second} component of the pair returned. These can be
+     *         used as the two arguments to {@link #parseFromEncoded(CharSequence)} to obtain {@link Credentials}
+     *         equivalent to the {@code credentials} passed to this method again.
+     */
+    Pair<String, String> getAsEncodedString(Credentials credentials);
+    
+    /**
+     * The inverse for {@link #getAsEncodedString(Credentials)}
+     */
+    Credentials parseFromEncoded(CharSequence encoded, String salt);
 }

java/com.sap.sse.aicore/src/com/sap/sse/aicore/impl/CredentialsImpl.java

@@ -94,6 +94,18 @@ public class CredentialsImpl implements Credentials {
         return token;
     }
 
+    String getClientId() {
+        return clientId;
+    }
+
+    String getClientSecret() {
+        return clientSecret;
+    }
+
+    URL getXsuaaUrl() {
+        return xsuaaUrl;
+    }
+
     String fetchToken() throws URISyntaxException, UnsupportedOperationException, ClientProtocolException, IOException, ParseException {
         final HttpPost postRequest = new HttpPost(new URI(xsuaaUrl.toString() + CLIENT_CREDENTIALS_PATH));
         postRequest.setHeader("Content-Type", "application/x-www-form-urlencoded");

java/com.sap.sse.aicore/src/com/sap/sse/aicore/impl/CredentialsParserImpl.java

@@ -3,6 +3,11 @@ package com.sap.sse.aicore.impl;
 import java.io.IOException;
 import java.io.Reader;
 import java.net.MalformedURLException;
+import java.util.Base64;
+import java.util.Random;
+
+import javax.crypto.Cipher;
+import javax.crypto.spec.SecretKeySpec;
 
 import org.json.simple.JSONObject;
 import org.json.simple.parser.JSONParser;
@@ -10,6 +15,7 @@ import org.json.simple.parser.ParseException;
 
 import com.sap.sse.aicore.Credentials;
 import com.sap.sse.aicore.CredentialsParser;
+import com.sap.sse.common.Util.Pair;
 
 public class CredentialsParserImpl implements CredentialsParser {
     private final static String CLIENT_ID = "clientid";
@@ -44,4 +50,60 @@ public class CredentialsParserImpl implements CredentialsParser {
         final String aiApiUrl = (String) serviceURLs.get(AI_API_URL);
         return new CredentialsImpl(clientId, clientSecret, url, identityZone, identityZoneId, appName, aiApiUrl);
     }
+
+    @Override
+    public Pair<String, String> getAsEncodedString(Credentials credentials) {
+        final String clientId = ((CredentialsImpl) credentials).getClientId();
+        final String clientSecret = ((CredentialsImpl) credentials).getClientSecret();
+        final String url = ((CredentialsImpl) credentials).getXsuaaUrl().toString();
+        final String identityZone = credentials.getIdentityZone();
+        final String identityZoneId = credentials.getIdentityZoneId();
+        final String appName = credentials.getAppName();
+        final String aiApiUrl = credentials.getAiApiUrl().toString();
+        final JSONObject jsonCredentials = new JSONObject();
+        jsonCredentials.put(CLIENT_ID, clientId);
+        jsonCredentials.put(CLIENT_SECRET, clientSecret);
+        jsonCredentials.put(URL, url);
+        jsonCredentials.put(IDENTITY_ZONE, identityZone);
+        jsonCredentials.put(IDENTITY_ZONE_ID, identityZoneId);
+        jsonCredentials.put(APP_NAME, appName);
+        final JSONObject serviceURLs = new JSONObject();
+        jsonCredentials.put(SERVICE_URLS, serviceURLs);
+        serviceURLs.put(AI_API_URL, aiApiUrl);
+        final String salt = createRandomSalt();
+        SecretKeySpec secretKey = new SecretKeySpec(salt.getBytes(), "AES"); // 16-byte key for AES
+        try {
+            Cipher cipher = Cipher.getInstance("AES");
+            cipher.init(Cipher.ENCRYPT_MODE, secretKey);
+            byte[] encryptedBytes = cipher.doFinal(jsonCredentials.toJSONString().getBytes());
+            return new Pair<>(Base64.getEncoder().encodeToString(encryptedBytes), salt);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private String createRandomSalt() {
+        final Random random = new Random();
+        final int numberOfCharacters = 16;
+        final char[] chars = new char[numberOfCharacters];
+        for (int i=0; i<numberOfCharacters; i++) {
+            chars[i] = (char) (((int) 'A') + random.nextInt((int) 'z' - (int) 'A'));
+        }
+        return new String(chars);
+    }
+
+    @Override
+    public Credentials parseFromEncoded(CharSequence encoded, String salt) {
+        final byte[] decodedBytes = Base64.getDecoder().decode(encoded.toString().getBytes());
+        final SecretKeySpec secretKey = new SecretKeySpec(salt.getBytes(), "AES"); // 16-byte key for AES
+        try {
+            final Cipher cipher = Cipher.getInstance("AES");
+            cipher.init(Cipher.DECRYPT_MODE, secretKey);
+            final byte[] decryptedBytes = cipher.doFinal(decodedBytes);
+            final String decryptedString = new String(decryptedBytes);
+            return parse(decryptedString);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
 }