@Override
    int updateInternal(byte[] input, int inputOffset, int inputLen, byte[] output,
            int outputOffset, int maximumLen) throws ShortBufferException {
        final int intialOutputOffset = outputOffset;

        final int bytesLeft = output.length - outputOffset;
        if (bytesLeft < maximumLen) {
            throw new ShortBufferWithoutStackTraceException("output buffer too small during update: "
                    + bytesLeft + " < " + maximumLen);
        }

        outputOffset += NativeCrypto.EVP_CipherUpdate(cipherCtx, output, outputOffset, input,
                inputOffset, inputLen);

        calledUpdate = true;

        return outputOffset - intialOutputOffset;
    }
The block size of the current mode.
common/src/main/java/org/conscrypt/OpenSSLEvpCipher.java