introduce constant for recurring error message

cryptomator · Feb 8, 2022 · 7d7b0aa · 7d7b0aa
1 parent 978af94
commit 7d7b0aa
Showing 1 changed file with 7 additions and 5 deletions.
diff --git a/src/main/java/org/cryptomator/cryptolib/common/ECKeyPair.java b/src/main/java/org/cryptomator/cryptolib/common/ECKeyPair.java
@@ -18,6 +18,8 @@
 
 public class ECKeyPair implements Destroyable {
 
+	private static final String INVALID_KEY_ERROR = "Invalid EC Key";
+
 	private final KeyPair keyPair;
 	private boolean destroyed;
 
@@ -46,28 +48,28 @@ public ECPublicKey getPublic() {
 	// validations taken from https://neilmadden.blog/2017/05/17/so-how-do-you-validate-nist-ecdh-public-keys/
 	private static KeyPair verify(KeyPair keyPair, ECParameterSpec curveParams) {
 		PublicKey pk = keyPair.getPublic();
-		Preconditions.checkArgument(pk instanceof ECPublicKey, "Not an EC key");
+		Preconditions.checkArgument(pk instanceof ECPublicKey, INVALID_KEY_ERROR);
 		Preconditions.checkArgument(curveParams.getCofactor() == 1, "Verifying points on curves with cofactor not supported"); // see "Step 4" in linked post
 		ECPublicKey publicKey = (ECPublicKey) pk;
 		EllipticCurve curve = curveParams.getCurve();
 
 		// Step 1: Verify public key is not point at infinity.
-		Preconditions.checkArgument(!ECPoint.POINT_INFINITY.equals(publicKey.getW()), "Invalid Key");
+		Preconditions.checkArgument(!ECPoint.POINT_INFINITY.equals(publicKey.getW()), INVALID_KEY_ERROR);
 
 		final BigInteger x = publicKey.getW().getAffineX();
 		final BigInteger y = publicKey.getW().getAffineY();
 		final BigInteger p = ((ECFieldFp) curve.getField()).getP();
 
 		// Step 2: Verify x and y are in range [0,p-1]
-		Preconditions.checkArgument(x.compareTo(BigInteger.ZERO) >= 0 && x.compareTo(p) < 0, "Invalid Key");
-		Preconditions.checkArgument(y.compareTo(BigInteger.ZERO) >= 0 && y.compareTo(p) < 0, "Invalid Key");
+		Preconditions.checkArgument(x.compareTo(BigInteger.ZERO) >= 0 && x.compareTo(p) < 0, INVALID_KEY_ERROR);
+		Preconditions.checkArgument(y.compareTo(BigInteger.ZERO) >= 0 && y.compareTo(p) < 0, INVALID_KEY_ERROR);
 
 		// Step 3: Verify that y^2 == x^3 + ax + b (mod p)
 		final BigInteger a = curve.getA();
 		final BigInteger b = curve.getB();
 		final BigInteger ySquared = y.modPow(BigInteger.valueOf(2), p);
 		final BigInteger xCubedPlusAXPlusB = x.modPow(BigInteger.valueOf(3), p).add(a.multiply(x)).add(b).mod(p);
-		Preconditions.checkArgument(ySquared.equals(xCubedPlusAXPlusB), "Invalid key");
+		Preconditions.checkArgument(ySquared.equals(xCubedPlusAXPlusB), INVALID_KEY_ERROR);
 
 		return keyPair;
 	}