1 thought on “MD5 value: and CRC value: What is it?”
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MD5, CRC and Windows original CD verification Date: 2005-9-3 Publisher: zhouhjss md5, CRC and Windows original CD verification
1, verification of verification Purpose, generally speaking, is it used to determine whether the CD or mirror is the original Copy (note: not to verify whether it is a copy of the original ISO file! Except for special requirements.)
2, assumptions For the premise, we know that the original CD -ROM ISO (of course, the virtual mirror has different formats, not necessarily the ISO) MD5 value and the original CRC value. 3P!: L
3, the scope of applicable, as far as the verification of the original Windows, MD5 can verify whether the mirror file at hand is a copy of the original ISO file (note: it is file). If the MD5 value is different, it is not a copy of the source ISO. CRC can check whether the mirror of our hand is the image of the original CD (note: not file) or Copy. 67G 4, MD5 problems: If we make the original version with different tools, and see the same as the MD5 value? It must be different. Use CRC to check, and the value is definitely the same. Because MD5 is a verified file, CRC is verified with a CD. In other words, there are many mirror files with different md5 values on the Internet that can also have a lot of md5 values, but the CRC values are the same. In addition, MD5 cannot be used to check the CD. 5. Suggestion: Whether the CRC check is the original Copy or mirror. If the download file is downloaded and the downloader gives the MD5 value, you can use the MD5 to check (but this value is not necessarily connected with whether the original mirror image is not necessarily connected, and only whether there is a problem with the download process species). 6, question of CRC verification From the results, AutoCRC just said that this .iso was effective (valid). But it did not tell me whether the file I CRC was the same as the other 505M .iso file. In other words, as long as it is successful from any CD -ROM to the ISO file on the hard disk, the verification of the CRC is correct, or Valid, right? Essence wrong! a, when using CDIMAGE to make a CD, the -x parameter should be added. After the production is successful, it can be verified by CRC. If the original CD is modified, it will definitely not pass (the situation where the CRC check is not re -added). 1P | gg b, after passing, depends on whether the specific value inside is consistent with the original version! L md5: The name of a message summary algorithm (also known as one -way laidance function). Through a certain algorithm, it ultimately generates a 128 -bit (BIT) verification value (a 32 -bit hexadecimal number) based on the source data. The most common application of MD5 is in cryptography. This article mainly uses it to verify the completeness of the file -if you find it difficult to understand the above text, then you can simply think that MD5 is a 128 -bit digital signature for school for schools for schools for schools for school Whether the file can be modified. Crc.exe: CD -ROM test software, Microsoft added this verification information on the CD after Win2000.
MD5, CRC and Windows original CD verification
Date: 2005-9-3 Publisher: zhouhjss
md5, CRC and Windows original CD verification
1, verification of verification Purpose, generally speaking, is it used to determine whether the CD or mirror is the original Copy (note: not to verify whether it is a copy of the original ISO file! Except for special requirements.)
2, assumptions For the premise, we know that the original CD -ROM ISO (of course, the virtual mirror has different formats, not necessarily the ISO) MD5 value and the original CRC value. 3P!: L
3, the scope of applicable, as far as the verification of the original Windows, MD5 can verify whether the mirror file at hand is a copy of the original ISO file (note: it is file). If the MD5 value is different, it is not a copy of the source ISO. CRC can check whether the mirror of our hand is the image of the original CD (note: not file) or Copy. 67G
4, MD5 problems: If we make the original version with different tools, and see the same as the MD5 value? It must be different. Use CRC to check, and the value is definitely the same. Because MD5 is a verified file, CRC is verified with a CD. In other words, there are many mirror files with different md5 values on the Internet that can also have a lot of md5 values, but the CRC values are the same. In addition, MD5 cannot be used to check the CD.
5. Suggestion: Whether the CRC check is the original Copy or mirror. If the download file is downloaded and the downloader gives the MD5 value, you can use the MD5 to check (but this value is not necessarily connected with whether the original mirror image is not necessarily connected, and only whether there is a problem with the download process species).
6, question of CRC verification
From the results, AutoCRC just said that this .iso was effective (valid). But it did not tell me whether the file I CRC was the same as the other 505M .iso file. In other words, as long as it is successful from any CD -ROM to the ISO file on the hard disk, the verification of the CRC is correct, or Valid, right? Essence
wrong!
a, when using CDIMAGE to make a CD, the -x parameter should be added. After the production is successful, it can be verified by CRC. If the original CD is modified, it will definitely not pass (the situation where the CRC check is not re -added). 1P | gg
b, after passing, depends on whether the specific value inside is consistent with the original version! L
md5: The name of a message summary algorithm (also known as one -way laidance function). Through a certain algorithm, it ultimately generates a 128 -bit (BIT) verification value (a 32 -bit hexadecimal number) based on the source data. The most common application of MD5 is in cryptography. This article mainly uses it to verify the completeness of the file -if you find it difficult to understand the above text, then you can simply think that MD5 is a 128 -bit digital signature for school for schools for schools for schools for school Whether the file can be modified.
Crc.exe: CD -ROM test software, Microsoft added this verification information on the CD after Win2000.