Android的，计算SHA-1散列的文件，最快的算法 [英] Android, calculating SHA-1 hash from file, fastest algorithm

问题描述

我有一个在Android SHA-1的性能问题。在C＃中我得到了约3秒，同样的计算为Android大约需要75秒来计算哈希值。我认为这个问题是从文件中读取的操作，但我不知道如何来提高性能。

I have a problem with SHA-1 performance on Android. In C# I get calculated hash in about 3s, same calculation for Android takes about 75s. I think the problem is in reading operation from file, but I'm not sure how to improve performance.

下面是我的哈希生成方法。

Here's my hash generation method.

private static String getSHA1FromFileContent(String filename)
    {

        try
        {
            MessageDigest digest = MessageDigest.getInstance("SHA-1");
            //byte[] buffer = new byte[65536]; //created at start.
            InputStream fis = new FileInputStream(filename);
            int n = 0;
            while (n != -1)
            {
                n = fis.read(buffer);
                if (n > 0)
                {
                    digest.update(buffer, 0, n);
                }
            }
            byte[] digestResult = digest.digest();
            return asHex(digestResult);
        }
        catch (Exception e)
        {
            return null;
        }
    }

任何想法我怎么能提高性能？​​

Any ideas how can I improve performance?

推荐答案

我测试了它在我的SGS（I9000），并花了0.806s生成散列为10.1MB的文件。

I tested it on my SGS (i9000) and it took 0.806s to generate the hash for a 10.1MB file.

唯一不同的是，在我的$ C $词现在用的BufferedInputStream除的FileInputStream和十六进制转换库的发现：

Only difference is that in my code i am using BufferedInputStream in addition to the FileInputStream and the hex conversion library found at:

的http://apachejava.blogspot.com/2011/02/hexconversions-convert-string-byte-byte.html

另外，我建议您关闭文件输入流在finally从句

Also I would suggest that you close your file input stream in a finally clause

这篇关于Android的，计算SHA-1散列的文件，最快的算法的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！