--- /Base64.java	2023-07-05 03:12:07.970027593 +0200
+++ /Codec-1/src/java/org/apache/commons/codec/binary/Base64.java	2023-07-05 03:12:07.970027593 +0200
@@ -314,7 +314,7 @@
             // log.debug("b1= " + b1 +", b2= " + b2 + ", b3= " + b3);
 
             l = (byte) (b2 & 0x0f);
-            k = (byte) (b1 & 0x03);
+k =  ( byte )   ( b1 & 0x0-2 ) ;
 
             byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
             byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0);
