#821 - signed codec

src/main/java/org/takes/facets/auth/codecs/CcSigned.java

@@ -0,0 +1,122 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2014-2018 Yegor Bugayenko
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package org.takes.facets.auth.codecs;
+
+import java.io.IOException;
+import java.security.InvalidKeyException;
+import java.security.Key;
+import java.security.NoSuchAlgorithmException;
+import java.util.Arrays;
+import javax.crypto.Mac;
+import org.takes.facets.auth.Identity;
+
+/**
+ * MAC codec which sign identity with provided algorithm and key.
+ * @author Kirill (g4s8.public@gmail.com)
+ * @version $Id$
+ * @since 1.11.1
+ */
+public final class CcSigned implements Codec {
+    /**
+     * Origin codec.
+     */
+    private final Codec cdc;
+    /**
+     * MAC algorithm.
+     */
+    private final String alg;
+    /**
+     * Secret key.
+     */
+    private final Key key;
+    /**
+     * Ctor.
+     * @param origin Origin codec
+     * @param algorithm Algorithm name
+     * @param secret Secret key
+     */
+    public CcSigned(
+        final Codec origin,
+        final String algorithm,
+        final Key secret
+    ) {
+        this.cdc = origin;
+        this.alg = algorithm;
+        this.key = secret;
+    }
+
+    @Override
+    public byte[] encode(final Identity identity) throws IOException {
+        final byte[] encoded = this.cdc.encode(identity);
+        final byte[] signature = this.mac().doFinal(encoded);
+        final byte[] signed = new byte[encoded.length + signature.length];
+        System.arraycopy(encoded, 0, signed, 0, encoded.length);
+        System.arraycopy(
+            signature,
+            0,
+            signed,
+            encoded.length,
+            signature.length
+        );
+        return signed;
+    }
+
+    @Override
+    public Identity decode(final byte[] bytes) throws IOException {
+        final Mac mac = this.mac();
+        if (bytes.length < mac.getMacLength()) {
+            throw new IOException("Invalid data size");
+        }
+        final byte[] signature = new byte[mac.getMacLength()];
+        final byte[] encoded = new byte[bytes.length - signature.length];
+        System.arraycopy(bytes, 0, encoded, 0, encoded.length);
+        System.arraycopy(
+            bytes,
+            encoded.length,
+            signature,
+            0,
+            signature.length
+        );
+        final byte[] actual = mac.doFinal(encoded);
+        if (!Arrays.equals(actual, signature)) {
+            throw new IOException("Bad signature");
+        }
+        return this.cdc.decode(encoded);
+    }
+
+    /**
+     * Obtain MAC instance.
+     * @return Initialized MAC
+     * @throws IOException If algorithm missed or invalid key
+     */
+    private Mac mac() throws IOException {
+        try {
+            final Mac mac = Mac.getInstance(this.alg);
+            mac.init(this.key);
+            return mac;
+        } catch (final NoSuchAlgorithmException | InvalidKeyException err) {
+            throw new IOException(err);
+        }
+    }
+}

src/test/java/org/takes/facets/auth/codecs/CcSignedTest.java

@@ -0,0 +1,64 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2014-2018 Yegor Bugayenko
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package org.takes.facets.auth.codecs;
+
+import java.io.IOException;
+import javax.crypto.spec.SecretKeySpec;
+import org.hamcrest.MatcherAssert;
+import org.hamcrest.Matchers;
+import org.junit.Test;
+import org.takes.facets.auth.Identity;
+
+/**
+ * Test case for {@link CcSigned}.
+ * @author Kirill (g4s8.public@gmail.com)
+ * @version $Id$
+ * @since 1.11.1
+ * @checkstyle JavadocMethodCheck (500 lines)
+ * @checkstyle MagicNumber (500 line)
+ */
+public final class CcSignedTest {
+    @Test
+    public void signAndVerify() throws IOException {
+        final String urn = "urn:github:346236";
+        final String alg = "HmacSHA1";
+        final CcSigned target = new CcSigned(
+            new CcTest(),
+            alg,
+            new SecretKeySpec(
+                new byte[]{
+                    (byte) -80, (byte) -46, (byte) 7, (byte) -102,
+                    (byte) 106, (byte) -25, (byte) -61, (byte) 80,
+                    (byte) 112, (byte) 103, (byte) -47, (byte) -52,
+                    (byte) 0, (byte) 124, (byte) 86, (byte) 113,
+                },
+                alg
+            )
+        );
+        MatcherAssert.assertThat(
+            target.decode(target.encode(new Identity.Simple(urn))).urn(),
+            Matchers.equalTo(urn)
+        );
+    }
+}