[feature] Facility for listing providers and algorithms

Author: adamretter

src/main/java/ro/kuberam/libs/java/crypto/CryptoError.java

@@ -22,6 +22,7 @@
 public enum CryptoError {
 
     UNKNOWN_ALGORITH("crypto:unknown-algorithm", "The specified algorithm is not supported."),
+    UNKNOWN_PROVIDER("crypto:unknown-provider", "The specified provider is not available."),
     SIGNATURE_TYPE("crypto:signature-type", "The specified signature type is not supported."),
     UNREADABLE_KEYSTORE("crypto:unreadable-keystore", "I/O error while reading keystore, or the password is incorrect."),
     DENIED_KEYSTORE("crypto:denied-keystore", "Permission denied to read keystore."),

src/main/java/ro/kuberam/libs/java/crypto/digest/Hash.java

@@ -22,8 +22,7 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.charset.StandardCharsets;
-import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
+import java.security.*;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -33,8 +32,7 @@
 import ro.kuberam.libs.java.crypto.utils.HexString;
 
 import javax.annotation.Nullable;
-import java.util.Base64;
-import java.util.Optional;
+import java.util.*;
 
 /**
  * Implements the crypto:hash() function.
@@ -47,16 +45,20 @@ public class Hash {
 	private static final Logger LOG = LogManager.getLogger(Hash.class);
 
 	public static String hashString(final String data, final String algorithm) throws CryptoException {
-		return hashString(data, algorithm, null);
+		return hashString(data, algorithm, null, null);
 	}
 
-	public static String hashString(final String data, final String algorithm, final @Nullable String format)
+	public static String hashString(final String data, final String algorithm, @Nullable final String provider) throws CryptoException {
+		return hashString(data, algorithm, provider, null);
+	}
+
+	public static String hashString(final String data, final String algorithm, @Nullable final String provider, final @Nullable String format)
 			throws CryptoException {
 
 		// TODO: validate the format
 		final String actualFormat = Optional.ofNullable(format).filter(str -> !str.isEmpty()).orElse("base64");
 
-		final MessageDigest messageDigester = getMessageDigester(algorithm);
+		final MessageDigest messageDigester = getMessageDigester(algorithm, provider);
 		messageDigester.update(data.getBytes(StandardCharsets.UTF_8));
 
 		final byte[] resultBytes = messageDigester.digest();
@@ -70,17 +72,22 @@ public static String hashString(final String data, final String algorithm, final
 
 	public static String hashBinary(final InputStream data, final String algorithm)
 			throws CryptoException, IOException {
-		return hashBinary(data, algorithm, null);
+		return hashBinary(data, algorithm, null, null);
+	}
+
+	public static String hashBinary(final InputStream data, final String algorithm, @Nullable final String provider)
+			throws CryptoException, IOException {
+		return hashBinary(data, algorithm, provider, null);
 	}
 
-	public static String hashBinary(final InputStream data, final String algorithm, @Nullable final String format)
+	public static String hashBinary(final InputStream data, final String algorithm, @Nullable final String provider, @Nullable final String format)
 			throws CryptoException, IOException {
 
 		// TODO: validate the format
 		final String actualFormat = Optional.ofNullable(format).filter(str -> !str.isEmpty()).orElse("base64");
 
 		final byte[] resultBytes;
-		final MessageDigest messageDigester = getMessageDigester(algorithm);
+		final MessageDigest messageDigester = getMessageDigester(algorithm, provider);
 
 		final byte[] buf = new byte[Buffer.TRANSFER_SIZE];
 		int read = -1;
@@ -100,11 +107,88 @@ public static String hashBinary(final InputStream data, final String algorithm,
 		return result;
 	}
 
-	private static MessageDigest getMessageDigester(final String algorithm) throws CryptoException {
+	private static MessageDigest getMessageDigester(final String algorithm, @Nullable final String provider) throws CryptoException {
 		try {
-			return MessageDigest.getInstance(algorithm);
+			if (provider != null) {
+				return MessageDigest.getInstance(algorithm, provider);
+			} else {
+				return MessageDigest.getInstance(algorithm);
+			}
 		} catch (final NoSuchAlgorithmException e) {
 			throw new CryptoException(CryptoError.UNKNOWN_ALGORITH, e);
+		} catch (final NoSuchProviderException e) {
+			throw new CryptoException(CryptoError.UNKNOWN_PROVIDER, e);
+		}
+	}
+
+
+	/**
+	 * Returns a list of security providers which
+	 * offer hash services.
+	 *
+	 * @return the names of the security providers which
+	 *     offer hash services.
+	 */
+	public static List<String> listProviders() {
+		final List<String> hashProviders = new ArrayList<>();
+
+		final Provider[] providers = Security.getProviders();
+		for (final Provider provider : providers) {
+			final Set<Provider.Service> services = provider.getServices();
+			for (final Provider.Service service : services) {
+				if (service.getType().equals("MessageDigest")) {
+					hashProviders.add(provider.getName());
+					break;
+				}
+			}
 		}
+
+		return hashProviders;
+	}
+
+	/**
+	 * Returns a Map of all hash services from each
+	 * security provider.
+	 *
+	 * @return a map from key: `service provider name` to value: `algorithm name(s)`.
+	 */
+	public static Map<String, Set<String>> listAlgorithms() {
+		final Map<String, Set<String>> algorithms = new HashMap<>();
+
+		final Provider[] providers = Security.getProviders();
+		for (final Provider provider : providers) {
+			final Set<Provider.Service> services = provider.getServices();
+			for (final Provider.Service service : services) {
+				if (service.getType().equals("MessageDigest")) {
+
+					final Set<String> providerAlgs = algorithms.computeIfAbsent(provider.getName(), k -> new HashSet<>());
+					providerAlgs.add(service.getAlgorithm());
+				}
+			}
+		}
+
+		return algorithms;
+	}
+
+	/**
+	 * Returns a Map of all hash services from a
+	 * security provider.
+	 *
+	 * @param providerName the name of the security provider.
+	 *
+	 * @return the names of the algorithms provided by the security provider.
+	 */
+	public static Set<String> listAlgorithms(final String providerName) {
+		final Set<String> algorithms = new HashSet<>();
+
+		final Provider provider = Security.getProvider(providerName);
+		final Set<Provider.Service> services = provider.getServices();
+		for (final Provider.Service service : services) {
+			if (service.getType().equals("MessageDigest")) {
+				algorithms.add(service.getAlgorithm());
+			}
+		}
+
+		return algorithms;
 	}
 }