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Part one of question


On my server I am compressing all my files.
I am trying to put the original file/folder checksum on my records
What are the normal checksum for file and folders?

I think that md5 is and the others are?

added for clarification

I will be using more than one sumcheck. 3 or 5 avenues of sumcheck
Is there a standard for how to store sumcheck in a files for an app to uses later to verification a file
what are the different avenues of sumcheck types
so md* is one avenues and sha* is another one
So is md5 ok


I have 20TB SAN for storage, but the largest file I can store right now is 2gb. but I have good file version control.
I would reformat the drive but I do not have that level control on file system I just have control what files and folder to storing it.
eventually I will have full control and then I will put a custom file system on the SAN.
for now I am compressing *.ios of OS and splitting file up and compressing my projects so when I need to work on them I have a 1TB SSD I use for my active projects.
so I just push the whole projects folder to the san storage, when I send it I compress and split.. but I like to some check compress sumcheck compress file then push it to SAN. When I need projects or ISO A pull it from the SAN and put on the SSD

for processing power I have AMD Opteron 6348 Abu Dhabi 2.8GHz 12MB L2 Cache 16MB L3 Cache Socket G34 115W 12-Core Server Processor OS6348WKTCGHKWOF that should be good for a while.

in folder checksum

so if I will be checksum all file then how to put the contact of the folder together so I have a value for the data in folder



Part two of question


lightweight portable and installed app to use in ms windows from command line?
lightweight portable and installed app to use in Linux Ubuntu from command line?

part two and a half of question

is it easer to make a sumcheck app or interface with already done ones?

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3 回答 3

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对于 Windows： 

fsum SlavaSoft Inc.

和快和

FastSum - extremely fast utility for your files integrity control. FastSum calculates short and strong digests of your data via popular MD5 algorithm to use it as references checksums for ulterior data integrity verification. 

FastSum - Allows to rectify the errors occurring while data transfer. For example: Network transfers, CD-R and DVD burning and much more. It is developed for easy processing of a huge files count and has usable command-line interface. It is an analogue of a famous md5sum Unix platform utility.

和 MD5sums

MD5sums is win32 command line software to generate MD5 hashes of files
于 2013-07-09T12:05:49.063 回答
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第一部分：

md5sum广泛用于文件校验和。据悉，md5sum有其弱点。还有其他选择：

sha1sum or sha224sum sha256sum sha384sum sha512sum ...

以上所有工具都可以计算文件、字符串的校验和，但不能直接在目录上计算。它们用于文件。您可以递归地生成目录下的所有文件。

第二部分：

对不起，我不明白你想问什么。这两个句子都以问号结尾，但我读了之后，它们根本不是问题。

于 2013-07-08T21:52:35.250 回答
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文件和文件夹的正常校验和是多少？

通常，单独来看，术语“校验和”是指为给定文件生成的值。关键是校验和值足够独特，可以检测数据的变化，因此理想情况下，具有不同内容的 2 个文件不应具有相同的“校验和”。如果您的意思是您使用的校验和算法，那么这取决于您想要执行完整性的严格程度，在带宽/存储和计算时间方面您可以承受多少开销。

如果要将所有文件放入存档中，则只需验证存档的校验和，而不是单个文件。但是，如果有可能修改数据，那么对每个文件使用校验和可能是个好主意。

除了考虑使用哪种算法之外，您还需要考虑如何使用它。如果您想防止恶意干扰，那么您需要一个散列函数（校验和算法的加密强子集），并且应该将它与预先或附加到数据的秘密随机值一起使用）。

checksum=f(contents_of_file, secret_string);

毫无疑问，很快就会有人说 md5 不安全。事实并非如此。它不如其他方法安全，但比许多其他方法更安全。逆向 md5 哈希的难度随着时间的推移而降低，因为人们找到了更好的攻击方法。

有很多校验和方法：

奇偶校验 - 容易伪造 - 只检测数据中奇数的位翻转

循环冗余检查 - 再次容易伪造，但处理开销非常低

sha-1 - 类似于 md5，但有额外的散列轮次，导致更大但更安全的摘要

sha-256 - 再次相同但更安全。

对于 Linux，md5sum 带有 GNU coreutils 包（因此将在带有 Cygwin 的 MSWindows 上运行）并且有本地 MSWindowsNT 工具。

于 2013-07-08T21:57:20.847 回答