From 04711e846fda07ab7f3284f53316ac1e7b141e5a Mon Sep 17 00:00:00 2001
From: Kostas Tsiounis <kostas.tsiounis@ibm.com>
Date: Wed, 21 Jun 2023 09:50:28 -0400
Subject: [PATCH] Improve speed of cipher operations for large inputs

---
 .../com/sun/crypto/provider/CipherCore.java   | 59 +++++++++++++++----
 1 file changed, 46 insertions(+), 13 deletions(-)

diff --git a/src/java.base/share/classes/com/sun/crypto/provider/CipherCore.java b/src/java.base/share/classes/com/sun/crypto/provider/CipherCore.java
index 2cddea6399d..dc76dfa3e65 100644
--- a/src/java.base/share/classes/com/sun/crypto/provider/CipherCore.java
+++ b/src/java.base/share/classes/com/sun/crypto/provider/CipherCore.java
@@ -749,12 +749,26 @@ byte[] doFinal(byte[] input, int inputOffset, int inputLen)
         throws IllegalBlockSizeException, BadPaddingException {
         try {
             byte[] output = new byte[getOutputSizeByOperation(inputLen, true)];
-            byte[] finalBuf = prepareInputBuffer(input, inputOffset,
-                    inputLen, output, 0);
+            int outputOffset = 0;
+            int outLen = 0;
+
+            if (inputLen > 0) {
+                /*
+                 * Call the update() method to get rid of as many bytes as
+                 * possible before potentially copying array.
+                 */
+                int updateOutLen = update(input, inputOffset, inputLen, output, outputOffset);
+                inputOffset = inputLen;
+                inputLen = 0;
+                outputOffset += updateOutLen;
+                outLen = updateOutLen;
+            }
+
+            byte[] finalBuf = prepareInputBuffer(input, inputOffset, inputLen, output, outputOffset);
             int finalOffset = (finalBuf == input) ? inputOffset : 0;
             int finalBufLen = (finalBuf == input) ? inputLen : finalBuf.length;
 
-            int outLen = fillOutputBuffer(finalBuf, finalOffset, output, 0,
+            outLen += fillOutputBuffer(finalBuf, finalOffset, output, outputOffset,
                     finalBufLen, input);
 
             endDoFinal();
@@ -818,13 +832,6 @@ int doFinal(byte[] input, int inputOffset, int inputLen, byte[] output,
         int estOutSize = getOutputSizeByOperation(inputLen, true);
         int outputCapacity = checkOutputCapacity(output, outputOffset,
                 estOutSize);
-        int offset = outputOffset;
-        byte[] finalBuf = prepareInputBuffer(input, inputOffset,
-                inputLen, output, outputOffset);
-        byte[] internalOutput = null; // for decrypting only
-
-        int finalOffset = (finalBuf == input) ? inputOffset : 0;
-        int finalBufLen = (finalBuf == input) ? inputLen : finalBuf.length;
 
         if (decrypting) {
             // if the size of specified output buffer is less than
@@ -835,18 +842,44 @@ int doFinal(byte[] input, int inputOffset, int inputLen, byte[] output,
             if (outputCapacity < estOutSize) {
                 cipher.save();
             }
+        }
+
+        int outLen = 0;
+        int estFinalBuffSize = estOutSize;
+        if (inputLen > 0) {
+            /*
+             * Call the update() method to get rid of as many bytes as
+             * possible before potentially copying array.
+             */
+            int updateOutLen = update(input, inputOffset, inputLen, output, outputOffset);
+            inputOffset = inputLen;
+            inputLen = 0;
+            outputOffset += updateOutLen;
+            outLen += updateOutLen;
+            estFinalBuffSize -= updateOutLen;
+        }
+
+        int offset = outputOffset;
+        byte[] finalBuf = prepareInputBuffer(input, inputOffset, inputLen, output, outputOffset);
+        byte[] internalOutput = null; // for decrypting only
+
+        int finalOffset = (finalBuf == input) ? inputOffset : 0;
+        int finalBufLen = (finalBuf == input) ? inputLen : finalBuf.length;
+
+        if (decrypting) {
             if (outputCapacity < estOutSize || padding != null) {
                 // create temporary output buffer if the estimated size is larger
                 // than the user-provided buffer or a padding needs to be removed
                 // before copying the unpadded result to the output buffer
-                internalOutput = new byte[estOutSize];
+                internalOutput = new byte[estFinalBuffSize];
                 offset = 0;
             }
         }
 
         byte[] outBuffer = (internalOutput != null) ? internalOutput : output;
-        int outLen = fillOutputBuffer(finalBuf, finalOffset, outBuffer,
+        int outBuffLen = fillOutputBuffer(finalBuf, finalOffset, outBuffer,
                 offset, finalBufLen, input);
+        outLen += outBuffLen;
 
         if (decrypting) {
 
@@ -860,7 +893,7 @@ int doFinal(byte[] input, int inputOffset, int inputLen, byte[] output,
             // copy the result into user-supplied output buffer
             if (internalOutput != null) {
                 System.arraycopy(internalOutput, 0, output, outputOffset,
-                    outLen);
+                    outBuffLen);
                 // decrypt mode. Zero out output data that's not required
                 Arrays.fill(internalOutput, (byte) 0x00);
             }