多页 tiff 文档的校验和
我想计算可能无法放入内存的大型 tiff 文件的校验和。 如果我计算每个页面的校验和，然后计算页面校验和数组的校验和，我会得到一个可靠的值吗？或者我会遇到一个我没有看到的数学问题，唯一正确的方法是事实上与整个事情有关吗？
谢谢！
I want to calculate the checksum for a large tiff file that might not fit in memory. Will I get a reliable value if I instead calculate the checksum of every page and then calculate the checksum of the array of page checksums or will I run into a mathematical problem that I am not seeing and the only correct way to do it is to in fact work with the whole thing?
Thanks!
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我不知道是否正确理解了这个问题，但是对于大多数校验和算法，您只需要加载 记忆消息的一小部分。 因此，可以在流而不是内存位置上进行操作，并且已经完成之前。
编辑：
我只知道在对短消息进行校验和时必须小心Adler-32，你不会覆盖整个哈希空间，并且误报的可能性更大（是的，校验和数组会可能是一条短信）。
对于加密哈希，我真的不知道。 我的直觉是 md5(msg1 + msg2 + ...) 与 md5(md5(msg1) + md5(msg2) + ...) 一样可靠，但我们必须等待比我更聪明的人给出明确的答案:)
I don't know if understood the question correctly, but with most checksum algorithms you only have to load a small part of the message to memory. Because of that operating on the streams instead of memory locations is possible and has been done before.
Edit:
I only know that you have to be careful with Adler-32 when checksumming short messages, you would not be covering the whole hash space and false positives are more likely (yest, the array of checksums would probably be a short message).
With crypto hashes I honestly don't know. My intuition is that md5(msg1 + msg2 + ...) is as reliable as md5(md5(msg1) + md5(msg2) + ...) but we'll have to wait for someone smarter than me to give definitive answer :)