1 files changed, 75 insertions, 0 deletions
diff --git a/pg/src/main/java/org/spongycastle/openpgp/operator/bc/BcUtil.java b/pg/src/main/java/org/spongycastle/openpgp/operator/bc/BcUtil.java
new file mode 100644
index 00000000..c3be8c83
--- /dev/null
+++ b/pg/src/main/java/org/spongycastle/openpgp/operator/bc/BcUtil.java
@@ -0,0 +1,75 @@
+package org.spongycastle.openpgp.operator.bc;
+
+import java.io.InputStream;
+
+import org.spongycastle.crypto.BlockCipher;
+import org.spongycastle.crypto.BufferedBlockCipher;
+import org.spongycastle.crypto.io.CipherInputStream;
+import org.spongycastle.crypto.modes.CFBBlockCipher;
+import org.spongycastle.crypto.modes.OpenPGPCFBBlockCipher;
+import org.spongycastle.crypto.params.KeyParameter;
+import org.spongycastle.crypto.params.ParametersWithIV;
+import org.spongycastle.openpgp.operator.PGPDataDecryptor;
+import org.spongycastle.openpgp.operator.PGPDigestCalculator;
+
+class BcUtil
+{
+    static BufferedBlockCipher createStreamCipher(boolean forEncryption, BlockCipher engine, boolean withIntegrityPacket, byte[] key)
+    {
+        BufferedBlockCipher c;
+
+        if (withIntegrityPacket)
+        {
+            c = new BufferedBlockCipher(new CFBBlockCipher(engine, engine.getBlockSize() * 8));
+        }
+        else
+        {
+            c = new BufferedBlockCipher(new OpenPGPCFBBlockCipher(engine));
+        }
+
+        KeyParameter keyParameter = new KeyParameter(key);
+
+        if (withIntegrityPacket)
+        {
+            c.init(forEncryption, new ParametersWithIV(keyParameter, new byte[engine.getBlockSize()]));
+        }
+        else
+        {
+            c.init(forEncryption, keyParameter);
+        }
+
+        return c;
+    }
+
+    public static PGPDataDecryptor createDataDecryptor(boolean withIntegrityPacket, BlockCipher engine, byte[] key)
+    {
+        final BufferedBlockCipher c = createStreamCipher(false, engine, withIntegrityPacket, key);
+
+        return new PGPDataDecryptor()
+        {
+            public InputStream getInputStream(InputStream in)
+            {
+                return new CipherInputStream(in, c);
+            }
+
+            public int getBlockSize()
+            {
+                return c.getBlockSize();
+            }
+
+            public PGPDigestCalculator getIntegrityCalculator()
+            {
+                return new SHA1PGPDigestCalculator();
+            }
+        };
+    }
+
+    public static BufferedBlockCipher createSymmetricKeyWrapper(boolean forEncryption, BlockCipher engine, byte[] key, byte[] iv)
+    {
+        BufferedBlockCipher c = new BufferedBlockCipher(new CFBBlockCipher(engine, engine.getBlockSize() * 8));
+
+        c.init(forEncryption, new ParametersWithIV(new KeyParameter(key), iv));
+
+        return c;
+    }
+}