Fix BN resizing issues

dufkan · Jul 6, 2021 · 62ea961 · 62ea961
1 parent 05cbf33
commit 62ea961
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Showing 2 changed files with 23 additions and 17 deletions.
diff --git a/applet/src/main/java/applet/MainApplet.java b/applet/src/main/java/applet/MainApplet.java
@@ -139,7 +139,7 @@ private void sign(APDU apdu) {
  signature.set_size((short) 64);
  signature.from_byte_array((short) 64, (short) 0, ramArray, (short) 0);
  signature.mod(curveOrder);
- signature.shrink();
+ signature.deep_resize((short) 32);
 
  // Compute signature s = r + ex
  signature.mod_mult(privateKey, signature, curveOrder);
@@ -157,18 +157,22 @@ private void encodeEd25519(ECPoint point, byte[] buffer, short offset) {
  point.getW(ramArray, (short) 0);
 
  // Compute X
+ transformX.set_size((short) 32);
  transformX.from_byte_array((short) 32, (short) 0, ramArray, (short) 1);
+ transformY.set_size((short) 32);
  transformY.from_byte_array((short) 32, (short) 0, ramArray, (short) 33);
  transformX.mod_sub(transformA3, curve.pBN);
  transformX.mod_mult(transformX, transformC, curve.pBN);
  transformY.mod_inv(curve.pBN);
  transformX.mod_mult(transformX, transformY, curve.pBN);
+ transformX.deep_resize((short) 32);
 
  boolean x_bit = transformX.is_odd();
 
  // Compute Y
  transformX.from_byte_array((short) 32, (short) 0, ramArray, (short) 1);
  transformX.mod_sub(transformA3, curve.pBN);
+ transformY.set_size((short) 32);
  transformY.copy(transformX);
  transformX.decrement_one();
  transformY.mod_add(Bignat_Helper.ONE, curve.pBN);
@@ -197,7 +201,7 @@ private void deterministicNonce(byte[] msg, short offset, short len) {
  privateNonce.set_size((short) 64);
  privateNonce.from_byte_array((short) 64, (short) 0, ramArray, (short) 0);
  privateNonce.mod(curveOrder);
- privateNonce.shrink();
+ privateNonce.deep_resize((short) 32);
  }
 
  private void randomNonce() {

diff --git a/applet/src/test/java/tests/AppletTest.java b/applet/src/test/java/tests/AppletTest.java
@@ -62,21 +62,23 @@ public void keygen_and_sign() throws Exception {
 
  byte[] pubkeyBytes = keygen(cm);
 
- byte[] data = new byte[32];
- for(int i = 0; i < data.length; ++i)
- data[i] = (byte) (0xff & i);
+ for(int j = 0; j < 256; ++j) {
+ byte[] data = new byte[32];
+ for (int i = 0; i < data.length; ++i)
+ data[i] = (byte) ((0xff & i) + j);
 
- final CommandAPDU cmd = new CommandAPDU(Consts.CLA_ED25519, Consts.INS_SIGN,0, 0, data);
- final ResponseAPDU responseAPDU = cm.transmit(cmd);
- Assert.assertNotNull(responseAPDU);
- Assert.assertEquals(0x9000, responseAPDU.getSW());
- Assert.assertNotNull(responseAPDU.getBytes());
- Assert.assertEquals(32 + 32, responseAPDU.getData().length);
- EdDSAParameterSpec spec = EdDSANamedCurveTable.getByName(EdDSANamedCurveTable.ED_25519);
- Signature sgr = new EdDSAEngine(MessageDigest.getInstance(spec.getHashAlgorithm()));
- PublicKey pubKey = new EdDSAPublicKey(new EdDSAPublicKeySpec(pubkeyBytes, spec));
- sgr.initVerify(pubKey);
- sgr.update(data);
- Assert.assertTrue(sgr.verify(responseAPDU.getData()));
+ final CommandAPDU cmd = new CommandAPDU(Consts.CLA_ED25519, Consts.INS_SIGN, 0, 0, data);
+ final ResponseAPDU responseAPDU = cm.transmit(cmd);
+ Assert.assertNotNull(responseAPDU);
+ Assert.assertEquals(0x9000, responseAPDU.getSW());
+ Assert.assertNotNull(responseAPDU.getBytes());
+ Assert.assertEquals(32 + 32, responseAPDU.getData().length);
+ EdDSAParameterSpec spec = EdDSANamedCurveTable.getByName(EdDSANamedCurveTable.ED_25519);
+ Signature sgr = new EdDSAEngine(MessageDigest.getInstance(spec.getHashAlgorithm()));
+ PublicKey pubKey = new EdDSAPublicKey(new EdDSAPublicKeySpec(pubkeyBytes, spec));
+ sgr.initVerify(pubKey);
+ sgr.update(data);
+ Assert.assertTrue(sgr.verify(responseAPDU.getData()));
+ }
  }
 }