PGPEncryptedDataGenerator: Allow extraction of session-key

Author: vanitasvitae

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

@@ -89,6 +89,7 @@ public class PGPEncryptedDataGenerator
     // If true, force generation of a session key, even if we only have a single password-based encryption method
     //  and could therefore use the S2K output as session key directly.
     private boolean forceSessionKey = true;
+    private SessionKeyExtractionCallback sessionKeyExtractionCallback = null;
 
     /**
      * Base constructor.
@@ -178,6 +179,11 @@ private byte[] createSessionInfo(
         return sessionInfo;
     }
 
+    public void setSessionKeyExtractionCallback(SessionKeyExtractionCallback callback)
+    {
+        this.sessionKeyExtractionCallback = callback;
+    }
+
     /**
      * Create an OutputStream based on the configured methods.
      * <p>
@@ -252,6 +258,11 @@ else if (directS2K)
             messageKey = sessionKey;
         }
 
+        if (sessionKeyExtractionCallback != null)
+        {
+            sessionKeyExtractionCallback.extractSessionKey(new PGPSessionKey(defAlgorithm, sessionKey));
+        }
+
         PGPDataEncryptor dataEncryptor = dataEncryptorBuilder.build(messageKey);
         digestCalc = dataEncryptor.getIntegrityCalculator();
 
@@ -579,4 +590,9 @@ public void close()
             this.finish();
         }
     }
+
+    public interface SessionKeyExtractionCallback
+    {
+        void extractSessionKey(PGPSessionKey sessionKey);
+    }
 }