spongycastle fails in android API < 21

[eehlers]

i am trying to run some spongycastle code in android:

        try {
            Security.addProvider(new org.spongycastle.jce.provider.BouncyCastleProvider());
            ECGenParameterSpec spec = new ECGenParameterSpec("P-256");
            KeyPairGenerator generator = KeyPairGenerator.getInstance("ECDSA", "SC");
            generator.initialize(spec, new SecureRandom());
            KeyPair keyPair = generator.generateKeyPair();
            ECPublicKey publicKey = (ECPublicKey) keyPair.getPublic();
            ECPrivateKey privateKey = (ECPrivateKey) keyPair.getPrivate();
            String publicKeyStr = publicKey.getW().getAffineX().toString() + ":" + publicKey.getW().getAffineY().toString();
            Log.d(TAG, publicKeyStr);
            Calendar c = Calendar.getInstance();
            Date d0 = c.getTime();
            c.add(Calendar.DATE, 1);
            Date expiry = c.getTime();
            String token = Jwts.builder()
                    .setIssuedAt(d0)
                    .setSubject("00000000-0000-0000-0000-000000000001")
                    .setExpiration(expiry)
                    .signWith(privateKey, SignatureAlgorithm.ES256).compact();
            Log.d(TAG, token);
        } catch (Exception e) {
            Log.d(TAG, e.toString());
        }

in API version 21+, it works as expected.

in API version 18, it works in debug. in release, it fails in function generator.generateKeyPair() with java.lang.IllegalArgumentException: Invalid point.

in API version 16, it fails in function Jwts.builder().signWith() with io.jsonwebtoken.security.SignatureException: Invalid Elliptic Curve PrivateKey. can't recognise key type in ECDSA based signer.

any idea what i am doing wrong?

[SahilAshar]

I'm assuming you're doing all this on the Android Studio Emulator? Can you try testing this code out on Android 19 and seeing what the debug + production spits out?

[nienienienie]

any news on that?