How to export to CSV the Hash of each file (SHA-256 & MD5) that are inside a folder in Windows?

I receive files from the client and I need to make sure those files are healthy even after I process these files. What I want to beware of is a situation of possible tampering with already processed files. A customer error may occur for sending files with missing information and the customer wants to edit the original file to say the information was there. That's why I had the idea of producing a report with the hash of these files that are in the reception directory. I tried hard to make everything clearer and more intelligible, even though I didn't speak English.

Scene 1: I have a directory with several text files and I need to export the SHA-256 and MD5 hash calculations from each file to a CSV somewhere.

Scene 2: I have a directory with several subfolders with customer names and within these customers, other subfolders. How to extract SHA-256 & MD5 Hash from all files in these directories and subdirectories?

Solution

Something like the following should get you started. This finds the SHA256 hash for every file inside the current directory (not including subdirectories)

Get-ChildItem | Get-FileHash | Export-CSV -Path "C:\Temp\summary.csv"

PS C:\Users\Jan\Dropbox\py\advent_of_code> cat "C:\Temp\summary.csv"
#TYPE Microsoft.Powershell.Utility.FileHash
"Algorithm","Hash","Path"
"SHA256","8E8FF02948E62C54EF782373500CD0D97B8A2DA0F1655A6134B37284CF5BCE79","C:\Users\Jan\Dropbox\py\advent_of_code\20191201.in"
"SHA256","63E68322B7E8131CDDEFB77492EC7E1B8B8C46696772CE561850C854E4E8B6EA","C:\Users\Jan\Dropbox\py\advent_of_code\20191201.py"
"SHA256","FFF1D3F7F7FBDDC4CDC90E123D9BC7B0B7A450DC28F3A4F2D786701B4A9B279D","C:\Users\Jan\Dropbox\py\advent_of_code\20191204.py"
"SHA256","DE3662893F2779446AFC78B20E63F5250826D5F52206E5718E1A2713F876941E","C:\Users\Jan\Dropbox\py\advent_of_code\20191206.in"
"SHA256","B9381E11A442DDC8CF802F337F0487E9269800B145106FFDDB0E6472D8C6F129","C:\Users\Jan\Dropbox\py\advent_of_code\20191206.py"

If you really need both SHA256 and MD5:

$h = @(Get-ChildItem | Get-FileHash)
$h2 = ($h | Get-Item | Get-FileHash -Algorithm MD5)  
for ($i=0; $i -lt $h.Length; $i++) { 
    $h[$i] = [PSCustomObject]@{Path=$h[$i].Path; SHA256=$h[$i].Hash; MD5=$h2[$i].Hash} 
}
$h | Export-Csv "C:\Temp\expo.txt"

PS C:\Users\Jan\Dropbox\py\advent_of_code> cat "C:\Temp\expo.txt"
#TYPE System.Management.Automation.PSCustomObject
"Path","SHA256","MD5"
"C:\Users\Jan\Dropbox\py\advent_of_code\20191201.in","8E8FF02948E62C54EF782373500CD0D97B8A2DA0F1655A6134B37284CF5BCE79","11689BA3058C306DAA3651562621BE20"
"C:\Users\Jan\Dropbox\py\advent_of_code\20191201.py","63E68322B7E8131CDDEFB77492EC7E1B8B8C46696772CE561850C854E4E8B6EA","3F50E29C797ED4BD65122F8DA1208D4D"
"C:\Users\Jan\Dropbox\py\advent_of_code\20191204.py","FFF1D3F7F7FBDDC4CDC90E123D9BC7B0B7A450DC28F3A4F2D786701B4A9B279D","41094A3E067669F46C965D0E34EA5CA6"
"C:\Users\Jan\Dropbox\py\advent_of_code\20191206.in","DE3662893F2779446AFC78B20E63F5250826D5F52206E5718E1A2713F876941E","1A7571873E6B9430A2BFD846CA0B8AB7"
"C:\Users\Jan\Dropbox\py\advent_of_code\20191206.py","B9381E11A442DDC8CF802F337F0487E9269800B145106FFDDB0E6472D8C6F129","0CBB058D315944B7B5183E33FC780A4D"