com.badlogic.gdx.pay.server.impl.Security Maven / Gradle / Ivy

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package com.badlogic.gdx.pay.server.impl;

import com.badlogic.gdx.pay.server.util.Base64Util;

import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.PublicKey;
import java.security.Signature;
import java.security.SignatureException;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.X509EncodedKeySpec;

public class Security {
    private static final String KEY_FACTORY_ALGORITHM = "RSA";
    private static final String SIGNATURE_ALGORITHM = "SHA1withRSA";
    private static final SecurityLogger logger = new SecurityLogger() {
        @Override public void log (String message) {
            System.out.println(message);
        }
    };

    /**
     * Generates a PublicKey instance from a string containing the
     * Base64-encoded public key.
     *
     * @param encodedPublicKey Base64-encoded public key
     * @throws IllegalArgumentException if encodedPublicKey is invalid
     */
    public static PublicKey generatePublicKey(String encodedPublicKey) {
        try {
            byte[] decodedKey = Base64Util.decode(encodedPublicKey);
            KeyFactory keyFactory = KeyFactory.getInstance(KEY_FACTORY_ALGORITHM);
            return keyFactory.generatePublic(new X509EncodedKeySpec(decodedKey));
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        } catch (InvalidKeySpecException e) {
            System.out.println("Invalid key specification.");
            throw new IllegalArgumentException(e);
        }
    }

    /**
     * Verifies that the signature from the server matches the computed
     * signature on the data.  Returns true if the data is correctly signed.
     *
     * @param publicKey  public key associated with the developer account
     * @param signedData signed data from server
     * @param signature  server signature
     * @return true if the data and signature match
     */
    public static boolean verify(PublicKey publicKey, String signedData, String signature) {
        return verify(publicKey, signedData, signature, logger);
    }

    /**
     * Verifies that the signature from the server matches the computed
     * signature on the data.  Returns true if the data is correctly signed.
     *
     * @param publicKey  public key associated with the developer account
     * @param signedData signed data from server
     * @param signature  server signature
     * @param logger logger that will log any issues
     * @return true if the data and signature match
     */
    public static boolean verify(PublicKey publicKey, String signedData, String signature, SecurityLogger logger) {
        byte[] signatureBytes;
        try {
            signatureBytes = Base64Util.decode(signature);
            Signature sig = Signature.getInstance(SIGNATURE_ALGORITHM);
            sig.initVerify(publicKey);
            sig.update(signedData.getBytes());
            if (!sig.verify(signatureBytes)) {
                logger.log("Signature verification failed.");
                return false;
            }
            return true;
        } catch (NoSuchAlgorithmException e) {
            logger.log("NoSuchAlgorithmException.");
        } catch (InvalidKeyException e) {
            logger.log("Invalid key specification.");
        } catch (SignatureException e) {
            logger.log("Signature exception.");
        }
        return false;
    }

    public interface SecurityLogger {
        void log(String message);
    }
}