backport upstream BouncyCastle fixes

aligned with bcgit/bc-java@7b094ad188

app/src/main/java/org/bouncycastle/shaded/crypto/DefaultMultiBlockCipher.java

@@ -19,8 +19,14 @@ public abstract class DefaultMultiBlockCipher
         // TODO check if the underlying cipher supports the multiblock interface and call it directly?
 
         int resultLen = 0;
-        int blockSize = this.getMultiBlockSize();
-        
+        int blockSize = this.getBlockSize();
+        int len = blockCount * blockSize;
+        if (in == out)
+        {
+            in = new byte[len];
+            System.arraycopy(out, inOff, in, 0, len);
+            inOff = 0;
+        }
         for (int i = 0; i != blockCount; i++)
         {
             resultLen += this.processBlock(in, inOff, out, outOff + resultLen);

app/src/main/java/org/bouncycastle/shaded/util/Arrays.java

@@ -803,9 +803,7 @@ public final class Arrays
         int newLength = to - from;
         if (newLength < 0)
         {
-            StringBuffer sb = new StringBuffer(from);
-            sb.append(" > ").append(to);
-            throw new IllegalArgumentException(sb.toString());
+            throw new IllegalArgumentException(from + " > " + to);
         }
         return newLength;
     }

app/src/main/java/org/bouncycastle/shaded/util/Strings.java

@@ -23,16 +23,32 @@ public final class Strings {
         }
     }
 
-    public static String toLowerCase(String str) {
-        char[] charArray = str.toCharArray();
-        boolean z = false;
-        for (int i = 0; i != charArray.length; i++) {
-            char c = charArray[i];
-            if ('A' <= c && 'Z' >= c) {
-                charArray[i] = (char) ((c - 'A') + 97);
-                z = true;
+    /**
+     * A locale independent version of toLowerCase.
+     *
+     * @param string input to be converted
+     * @return a US ASCII lowercase version
+     */
+    public static String toLowerCase(String string)
+    {
+        boolean changed = false;
+        char[] chars = string.toCharArray();
+
+        for (int i = 0; i != chars.length; i++)
+        {
+            char ch = chars[i];
+            if ('A' <= ch && 'Z' >= ch)
+            {
+                changed = true;
+                chars[i] = (char)(ch - 'A' + 'a');
             }
         }
-        return z ? new String(charArray) : str;
+
+        if (changed)
+        {
+            return new String(chars);
+        }
+
+        return string;
     }
 }