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HASHFILE()

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HASHFILE(1,2,3,4)

 

PURPOSE

 

This function will get and verify a hash.

 

PARTS

 

1. sac        Required: - What to do:

 

       GetMD5 -  gets the file's "fingerprint" using MD5

       GetSHA1 gets the file's "fingerprint" using SHA1

       VerifyMD5 -  compares the hash of the file using MD5

       VerifySHA1 -  compares the hash of the file using SHA1

 

2.   f/c/e Required: - The file name including path

 

 

3.  f/c/e  This part depends on the option specified in part 1.

 

RETURN TYPE - Varies        

The return value depends on the option set in part 1.

 

GetMD5 / GetSHA1 - A - Returns the hash value or fingerprint

 

VerifyMD5 / VerifySHA1 - L - Returns true if the fingerprint matches otherwise returns false

 

COMMENTS

 

MD5 stands for Message Digest number 5, an algorithm that generates a unique, 128-bit cryptographic message digest value derived from the contents of an input stream.  A value such as this is considered to be a reliable fingerprint that can be used to verify the integrity of a file's contents. If as little as a single bit value in the file is modified, the MD5 checksum for the file changes. Forgery of a file in a way that causes MD5 to generate the same result as that for the original file is difficult.

 

SHA1 - is similar to MD5 but is 160-bit and is considered more secure than MD5.

 

Using a hash system provides a way to integrity check certain files.   You might check the hash of a file in order to verify a copy operation or to verify that a user update has been implemented based on a stored list of known hash codes or as a part of some other verification process.

 

NOTE: The special alpha constants above (GetMD5 , GetSHA1, VerifyMD5, and VerifySHA1) are defined in COMPILERCONSTANTS.TXT.

 

EXAMPLE

 

Define RetVal Type A Size 50

Define Match Type L

 

Start:

RetVal = HashFile(getMD5,'C:\TEMP\SomeFile.txt')

//does not have to be the same directory

Match = HashFile(VerifyMD5,'C:\TEMP\SomeOtherFileName.txt',RetVal)

if match

   msg "The files are the same."

else

   msg "The files are not the same."

endif

ret

 

 


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