Merge branch '1958-aead-parameters' into 'main'

1958 aead parameters

See merge request root/bc-java!64

Author: dghgit

core/src/main/java/org/bouncycastle/crypto/engines/AEADBaseEngine.java

@@ -0,0 +1,121 @@
+package org.bouncycastle.crypto.engines;
+
+import org.bouncycastle.crypto.CipherParameters;
+import org.bouncycastle.crypto.CryptoServicesRegistrar;
+import org.bouncycastle.crypto.DataLengthException;
+import org.bouncycastle.crypto.constraints.DefaultServiceProperties;
+import org.bouncycastle.crypto.modes.AEADCipher;
+import org.bouncycastle.crypto.params.AEADParameters;
+import org.bouncycastle.crypto.params.KeyParameter;
+import org.bouncycastle.crypto.params.ParametersWithIV;
+
+abstract class AEADBaseEngine
+    implements AEADCipher
+{
+    protected boolean forEncryption;
+    protected String algorithmName;
+    protected int KEY_SIZE;
+    protected int IV_SIZE;
+    protected int MAC_SIZE;
+    protected byte[] initialAssociatedText;
+    protected byte[] mac;
+
+    @Override
+    public String getAlgorithmName()
+    {
+        return algorithmName;
+    }
+
+    public int getKeyBytesSize()
+    {
+        return KEY_SIZE;
+    }
+
+    public int getIVBytesSize()
+    {
+        return IV_SIZE;
+    }
+
+    public byte[] getMac()
+    {
+        return mac;
+    }
+
+    public void reset()
+    {
+        reset(true);
+    }
+
+    public int processByte(byte in, byte[] out, int outOff)
+        throws DataLengthException
+    {
+        return processBytes(new byte[]{in}, 0, 1, out, outOff);
+    }
+
+    public void init(boolean forEncryption, CipherParameters params)
+    {
+        this.forEncryption = forEncryption;
+        KeyParameter key;
+        byte[] npub;
+        byte[] k;
+
+        if (params instanceof AEADParameters)
+        {
+            AEADParameters aeadParameters = (AEADParameters)params;
+            key = aeadParameters.getKey();
+            npub = aeadParameters.getNonce();
+            initialAssociatedText = aeadParameters.getAssociatedText();
+
+            int macSizeBits = aeadParameters.getMacSize();
+            if (macSizeBits != MAC_SIZE * 8)
+            {
+                throw new IllegalArgumentException("Invalid value for MAC size: " + macSizeBits);
+            }
+        }
+        else if (params instanceof ParametersWithIV)
+        {
+            ParametersWithIV withIV = (ParametersWithIV)params;
+            key = (KeyParameter)withIV.getParameters();
+            npub = withIV.getIV();
+            initialAssociatedText = null;
+        }
+        else
+        {
+            throw new IllegalArgumentException("invalid parameters passed to " + algorithmName);
+        }
+
+        if (key == null)
+        {
+            throw new IllegalArgumentException(algorithmName + " Init parameters must include a key");
+        }
+        if (npub == null || npub.length != IV_SIZE)
+        {
+            throw new IllegalArgumentException(algorithmName + " requires exactly " + IV_SIZE + " bytes of IV");
+        }
+
+        k = key.getKey();
+        if (k.length != KEY_SIZE)
+        {
+            throw new IllegalArgumentException(algorithmName + " key must be " + KEY_SIZE + " bytes long");
+        }
+
+        CryptoServicesRegistrar.checkConstraints(new DefaultServiceProperties(
+            this.getAlgorithmName(), 128, params, Utils.getPurpose(forEncryption)));
+
+        init(k, npub);
+        if (initialAssociatedText != null)
+        {
+            processAADBytes(initialAssociatedText, 0, initialAssociatedText.length);
+        }
+    }
+
+    protected abstract void init(byte[] key, byte[] iv);
+
+    protected void reset(boolean clearMac)
+    {
+        if (clearMac)
+        {
+            mac = null;
+        }
+    }
+}