Fix checksum conversion to base w

peterdettman · peterdettman · commit 1f1dc868a3ac · 2022-10-10T17:14:21.000+07:00
- innocuous for currently tested parameter sets
diff --git a/core/src/main/java/org/bouncycastle/pqc/crypto/sphincsplus/WotsPlus.java b/core/src/main/java/org/bouncycastle/pqc/crypto/sphincsplus/WotsPlus.java
@@ -84,7 +84,7 @@ public byte[] sign(byte[] M, byte[] skSeed, byte[] pkSeed, ADRS paramAdrs)
         }
         int len_2_bytes = (engine.WOTS_LEN2 * engine.WOTS_LOGW + 7) / 8;
         byte[] bytes = Pack.intToBigEndian(csum);
-        msg = Arrays.concatenate(msg, base_w(Arrays.copyOfRange(bytes, len_2_bytes, bytes.length), w, engine.WOTS_LEN2));
+        msg = Arrays.concatenate(msg, base_w(Arrays.copyOfRange(bytes, 4 - len_2_bytes, bytes.length), w, engine.WOTS_LEN2));
         byte[][] sig = new byte[engine.WOTS_LEN][];
         for (int i = 0; i < engine.WOTS_LEN; i++)
         {

Original file line number	Diff line number	Diff line change
`@@ -84,7 +84,7 @@ public byte[] sign(byte[] M, byte[] skSeed, byte[] pkSeed, ADRS paramAdrs)`
`84`	`84`	`}`
`85`	`85`	`int len_2_bytes = (engine.WOTS_LEN2 * engine.WOTS_LOGW + 7) / 8;`
`86`	`86`	`byte[] bytes = Pack.intToBigEndian(csum);`
`87`		`- msg = Arrays.concatenate(msg, base_w(Arrays.copyOfRange(bytes, len_2_bytes, bytes.length), w, engine.WOTS_LEN2));`
	`87`	`+ msg = Arrays.concatenate(msg, base_w(Arrays.copyOfRange(bytes, 4 - len_2_bytes, bytes.length), w, engine.WOTS_LEN2));`
`88`	`88`	`byte[][] sig = new byte[engine.WOTS_LEN][];`
`89`	`89`	`for (int i = 0; i < engine.WOTS_LEN; i++)`
`90`	`90`	`{`