[cp-patches] FYI: modification to PBEKDF2 inistialisation

[Raif S. Naffah]

hello there,

as suggested by Stephen, the attached patch, already committed, modifies 
the setup() method of the PBEKDF2 generator to check first for a raw 
byte array, to use as the underlying MAC's key material, in preference 
to a password (characters).  furthermore, the patch also allows the 
user, when passing a password, to specify a charset encoding to use 
when converting the password chars into bytes --UTF-8 remains the 
fallback charset encoding.

2006-04-19  Raif S. Naffah  <[EMAIL PROTECTED]>

        Suggested by Stephen White <[EMAIL PROTECTED]>
        * gnu/javax/crypto/prng/IPBE.java: Updated documentation.
        (ITERATION_COUNT): Removed modifiers.
        (PASSWORD): Likewise.
        (SALT): Likewise.
        (PASSWORD_ENCODING): New property.
        (DEFAULT_PASSWORD_ENCODING): New constant.
        * gnu/javax/crypto/prng/PBKDF2.java (setup): Check for MAC's raw key
        material (bytes) before a password (chars).


cheers;
rsn

Index: IPBE.java
===================================================================
RCS file: /cvsroot/classpath/classpath/gnu/javax/crypto/prng/IPBE.java,v
retrieving revision 1.2
diff -u -r1.2 IPBE.java
--- IPBE.java   13 Apr 2006 21:07:03 -0000      1.2
+++ IPBE.java   19 Apr 2006 11:49:06 -0000
@@ -39,29 +39,43 @@
 package gnu.javax.crypto.prng;

 /**
- * <p>Trivial interface to group Password-based encryption property names.</p>
+ * Trivial interface to group Password-based encryption property names and
+ * constants.
  */
 public interface IPBE
 {
-
-  // Constants
-  // -------------------------------------------------------------------------
-
   /**
    * Property name for the iteration count in a PBE algorithm. The property
    * associated with this is expected to be an [EMAIL PROTECTED] Integer}.
    */
-  public static final String ITERATION_COUNT = 
"gnu.crypto.pbe.iteration.count";
+  String ITERATION_COUNT = "gnu.crypto.pbe.iteration.count";

   /**
    * Property name for the password in a PBE algorithm. The property associated
    * with this is expected to be a char array.
    */
-  public static final String PASSWORD = "gnu.crypto.pbe.password";
+  String PASSWORD = "gnu.crypto.pbe.password";
+
+  /**
+   * Property name for the password character encoding in a PBE algorithm. The
+   * property associated with this is expected to be a String denoting a valid
+   * character-encoding name. If this property is not set, and a password is
+   * used, then [EMAIL PROTECTED] #DEFAULT_PASSWORD_ENCODING} will be used 
when converting
+   * the password character(s) to bytes.
+   */
+  String PASSWORD_ENCODING = "gnu.crypto.pbe.password.encoding";

   /**
    * Property name for the salt in a PBE algorithm. The property associated
    * with this is expected to be a byte array.
    */
-  public static final String SALT = "gnu.crypto.pbe.salt";
+  String SALT = "gnu.crypto.pbe.salt";
+
+  /**
+   * The default character set encoding name to be used if (a) a password is
+   * to be used as the source for a PBE-based Key Derivation Function (KDF) and
+   * (b) no character set encoding name was specified among the attributes used
+   * to initialize the instance.
+   */
+  String DEFAULT_PASSWORD_ENCODING = "UTF-8";
 }
Index: PBKDF2.java
===================================================================
RCS file: /cvsroot/classpath/classpath/gnu/javax/crypto/prng/PBKDF2.java,v
retrieving revision 1.2
diff -u -r1.2 PBKDF2.java
--- PBKDF2.java 13 Apr 2006 21:07:03 -0000      1.2
+++ PBKDF2.java 19 Apr 2006 11:53:15 -0000
@@ -127,23 +127,34 @@
         salt = s;
       }

+    byte[] macKeyMaterial;
     char[] password = (char[]) attributes.get(IPBE.PASSWORD);
     if (password != null)
       {
+        String encoding = (String) attributes.get(IPBE.PASSWORD_ENCODING);
+        if (encoding == null || encoding.trim().length() == 0)
+          encoding = IPBE.DEFAULT_PASSWORD_ENCODING;
+        else
+          encoding = encoding.trim();
+
         try
           {
-            macAttrib.put(IMac.MAC_KEY_MATERIAL,
-                          new String(password).getBytes("UTF-8"));
+            macKeyMaterial = new String(password).getBytes(encoding);
           }
         catch (UnsupportedEncodingException uee)
           {
-            throw new Error(uee.getMessage());
+            throw new IllegalArgumentException("Unknown or unsupported 
encoding: "
+                                               + encoding, uee);
           }
       }
+    else
+      macKeyMaterial = (byte[]) attributes.get(IMac.MAC_KEY_MATERIAL);
+
+    if (macKeyMaterial != null)
+      macAttrib.put(IMac.MAC_KEY_MATERIAL, macKeyMaterial);
     else if (!initialised)
-      {
-        throw new IllegalArgumentException("no password specified");
-      } // otherwise re-use previous password.
+      throw new IllegalArgumentException("Neither password nor key-material 
were specified");
+    // otherwise re-use previous password/key-material

     try
       {

pgpgXuTYYmyM9.pgp
Description: PGP signature