Added constructor

io-hotmoka-crypto-api/src/main/java/io/hotmoka/crypto/api/SignatureAlgorithm.java

@@ -68,7 +68,7 @@ public interface SignatureAlgorithm<T> {
 	 * 
 	 * @param encoding the encoded version of the public key
 	 * @return the public key
-	 * @throws InvalidKeySpecException if the {@code encoded} key does not match the expected specification
+	 * @throws InvalidKeySpecException if {@code encoding} does not match the expected specification
 	 */
 	PublicKey publicKeyFromEncoding(byte[] encoding) throws InvalidKeySpecException;
 
@@ -87,7 +87,7 @@ public interface SignatureAlgorithm<T> {
 	 * 
 	 * @param encoding the encoded version of the private key
 	 * @return the private key
-	 * @throws InvalidKeySpecException if the {@code encoded} key does not match the expected specification
+	 * @throws InvalidKeySpecException if {@code encoding} does not match the expected specification
 	 */
 	PrivateKey privateKeyFromEncoding(byte[] encoding) throws InvalidKeySpecException;
 

io-hotmoka-crypto/src/main/java/io/hotmoka/crypto/Entropies.java

@@ -17,6 +17,7 @@
 package io.hotmoka.crypto;
 
 import java.io.IOException;
+import java.nio.file.Path;
 import java.security.SecureRandom;
 
 import io.hotmoka.crypto.api.Entropy;
@@ -55,10 +56,27 @@ public static Entropy random() {
 	 * @return the entropy
 	 * @throws IOException if the PEM file cannot be read
 	 */
+	@Deprecated
 	public static Entropy load(String filePrefix) throws IOException {
 		return new EntropyImpl(filePrefix);
 	}
 
+	/**
+	 * Yields new entropy information read from a PEM file.
+	 * 
+	 * @param path the file
+	 * @return the entropy
+	 * @throws IOException if the PEM file cannot be read
+	 */
+	public static Entropy load(Path path) throws IOException {
+		long length = path.toFile().length();
+		// without this check, the access to the file would take very long and terminate with an error anyway
+		if (length > 1000L)
+			throw new IOException("The pem file " + path + " is too long for being a PEM file!");
+
+		return new EntropyImpl(path);
+	}
+
 	/**
 	 * Yields a copy of the given entropy.
 	 * 

io-hotmoka-crypto/src/main/java/io/hotmoka/crypto/internal/BIP39MnemonicImpl.java

@@ -86,16 +86,16 @@ public Stream<String> stream() {
     @Override
     public <R extends Comparable<? super R>> Account<R> toAccount(BiFunction<Entropy, byte[], Account<R>> accountCreator) {
         // each mnemonic word represents 11 bits
-        boolean[] bits = new boolean[words.length * 11];
+        var bits = new boolean[words.length * 11];
 
         // the transaction is always 32 bytes long
-        byte[] transaction = new byte[32];
+        var transaction = new byte[32];
 
         int bitsOfChecksum = words.length / 3;
-        boolean[] checksum = new boolean[bitsOfChecksum];
+        var checksum = new boolean[bitsOfChecksum];
 
         // the entropy uses the remaining number of bytes
-        byte[] entropy = new byte[(bits.length - bitsOfChecksum) / 8 - transaction.length];
+        var entropy = new byte[(bits.length - bitsOfChecksum) / 8 - transaction.length];
 
         int startOfTransaction = entropy.length * 8;
         int startOfChecksum = startOfTransaction + transaction.length * 8;
@@ -138,11 +138,11 @@ public <R extends Comparable<? super R>> Account<R> toAccount(BiFunction<Entropy
         	throw new RuntimeException("unexpected exception", e);
         }
 
-        byte[] merge = new byte[entropy.length + transaction.length];
+        var merge = new byte[entropy.length + transaction.length];
     	System.arraycopy(entropy, 0, merge, 0, entropy.length);
     	System.arraycopy(transaction, 0, merge, entropy.length, transaction.length);
         byte[] sha256 = digest.digest(merge);
-        boolean[] checksumRecomputed = new boolean[bitsOfChecksum];
+        var checksumRecomputed = new boolean[bitsOfChecksum];
         for (pos = 0; pos < bitsOfChecksum; pos++)
             checksumRecomputed[pos] = (sha256[pos] & (0x80 >>> (pos % 8))) != 0;
 

io-hotmoka-crypto/src/main/java/io/hotmoka/crypto/internal/EntropyImpl.java

@@ -77,6 +77,21 @@ public EntropyImpl(String filePrefix) throws IOException {
 			throw new IllegalArgumentException("illegal entropy length: 16 bytes expected");
 	}
 
+	/**
+	 * Reads the entropy information from a PEM file.
+	 * 
+	 * @param path the file
+	 * @throws IOException if the PEM file cannot be read
+	 */
+	public EntropyImpl(Path path) throws IOException {
+		try (var reader = new PemReader(new FileReader(path.toFile()))) {
+			entropy = reader.readPemObject().getContent();
+		}
+
+		if (entropy.length != 16)
+			throw new IllegalArgumentException("illegal entropy length: 16 bytes expected");
+	}
+
 	/**
 	 * Copy constructor.
 	 * 

io-hotmoka-marshalling/src/main/java/io/hotmoka/marshalling/internal/UnmarshallingContextImpl.java

@@ -23,6 +23,7 @@
 import java.math.BigInteger;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Objects;
 import java.util.function.Function;
 
 import io.hotmoka.marshalling.api.Marshallable;
@@ -69,8 +70,7 @@ protected void registerObjectUnmarshaller(ObjectUnmarshaller<?> ou) {
 	public <C> C readObject(Class<C> clazz) throws IOException {
 		@SuppressWarnings("unchecked")
 		var ou = (ObjectUnmarshaller<C>) objectUnmarshallers.get(clazz);
-		if (ou == null)
-			throw new IllegalStateException("missing object unmarshaller for class " + clazz.getName());
+		Objects.requireNonNull(ou, "Missing object unmarshaller for class " + clazz.getName());
 
 		return ou.read(this);
 	}