AES256加密/解密速度 [英] AES256 Encryption/Decryption speed

问题描述

我写这些加密和解密文件的应用程序。我使用AES256位密码使用CipherInputStream和CipherOutputStream为enryption /解密过程。

I am writing an application which encrypts and decrypts files. I am using CipherInputStream and CipherOutputStream for enryption/decryption process using AES256 bit cipher.

我的问题是，如果我把字节数组，写入文件的飞行大约需要2倍的时间比我是否解密文件中创建一个字节数组makeing加密。因为我了解AES加密和解密是对称的过程，他们应该采取的时间相同数额来完成这很奇怪。

My problem is if I take byte array and write to file makeing encryption on the fly it takes about 2 times less time than if I decrypt file creating a byte array. It is strange because as I know AES encryption and decryption are symmetric processes and they should take same amount of time to complete.

任何想法？

推荐答案

有很多在这里的贴子＃2抱怨慢I / Android上的O操作。很多时候，问题是一个坏块大小为执行日写操作。

There are a lot of postings here on Stackoverflow complaining about slow I/O operations on Android. Very often the problem is a bad block-size for performing th write operations.

在智能手机中使用闪存组织了几千字节的大块 - 因此最佳写入速度，你应该只写它的4KB块或多个

Flash memory as used in Smartphones is organized in large blocks of several kilobytes - therefore for optimal write speed you should only write blocks of 4KB or multiple of it.

这是8字节的块加密算法AES一样工作逐块 - 这可能会导致大量的性能消耗

Ciphers like AES work block-wise on blocks of 8 bytes - this may lead to massive performance drain.

我建议通过的BufferedOutputStream 4或16KB的缓冲器大小发送CipherOutputStream的输出。这应该显著加快行动的过程。

I would recommend to send the output of the CipherOutputStream through a BufferedOutputStream with a buffer size of 4 or 16 KB. This should significantly speed-up the process.

此外，你必须考虑写入到闪存总是比读书更慢。

Additionally you have to consider that writing to flash memory is always slower than reading.

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