Solved Powershell command to generate SHA512 Base64 checksum

Hi everyone,

Does anyone know the command to generate a SHA512 checksum with Base64 encoding?
Just to clarify, the standard encoding for SHA512 is HEX but the checksum I'm trying to verify was generated Base64 encoding.

Here's the command I'm using to generate the standard SHA512 HEX.

Get-FileHash -Path C:\Users\XXX\Downloads\FILENAME -Algorithm SHA512

But I don't know the command to generate SHA512 Base64.

No need to suggest installing a software, I'm aware of those, I prefer to use a command.

Thanks

PowerShell can interop with .NET so you should be able to use the ToBase64String method: Convert.ToBase64String Method (System)

I can't testify to it's accuracy but this according to AI. Co-pilot says:
One possible PowerShell command to generate SHA512 Base64 checksum for a file is:

# Get the hash of the file
$hash = Get-FileHash <path to input file> -Algorithm SHA512
# Convert hash to byte representation
$hashBytes = [System.Text.Encoding]::Unicode.GetBytes ($hash.Hash)
# Convert bytes to base64, then output to file
[System.Convert]::ToBase64String ($hashBytes) | Out-File <path to hash output file>

This command is based on the answer from Stack Overflow1. You can also use other hash algorithms that are supported by PowerShell, such as MD5, SHA1, SHA256, or SHA384. For more information, you can refer to the official documentation of the Get-FileHash cmdlet2. Alternatively, you can use the certutil.exe tool to generate and verify checksums in Windows34.

You can use the attached batch script to add Hash to context menu of files in Windows 8, Windows 10 and Windows 11.

glasskuter said:

I can't testify to it's accuracy but this according to AI. Co-pilot says:
One possible PowerShell command to generate SHA512 Base64 checksum for a file is:

# Get the hash of the file
$hash = Get-FileHash <path to input file> -Algorithm SHA512
# Convert hash to byte representation
$hashBytes = [System.Text.Encoding]::Unicode.GetBytes ($hash.Hash)
# Convert bytes to base64, then output to file
[System.Convert]::ToBase64String ($hashBytes) | Out-File <path to hash output file>

This command is based on the answer from Stack Overflow1. You can also use other hash algorithms that are supported by PowerShell, such as MD5, SHA1, SHA256, or SHA384. For more information, you can refer to the official documentation of the Get-FileHash cmdlet2. Alternatively, you can use the certutil.exe tool to generate and verify checksums in Windows34.

Click to expand...

Thanks for the input.

So I got the Hash of the file using

Get-FileHash <path to input file> -Algorithm SHA512

Click to expand...

29DA971D3A045CFB1243036BE2158967E22102689B87AAFB0C24A9B8EFC396DA6A88A0318312A24511CF41129AD3BA3FF125A3C75AB84B3FA058C078D01D7797

Then converted to byte representation

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Click to expand...

Then converted byte representation to base64

MjlEQTk3MUQzQTA0NUNGQjEyNDMwMzZCRTIxNTg5NjdFMjIxMDI2ODlCODdBQUZCMEMyNEE5QjhFRkMzOTZEQTZBODhBMDMxODMxMkEyNDUxMUNGNDExMjlBRDNCQTNGRjEyNUEzQzc1QUI4NEIzRkEwNThDMDc4RDAxRDc3OTc=

Click to expand...

And the base64 hash I get is different than what it should be (downloaded file from the internet)

Unsure if it's an error on my end or if the downloaded file is compromised. Most likely an error on my end.

I would appreciate if someone with a few min to spare could run the command on their end just to see if they end up with the same base64

The SHA512 hash (step 1) should be correct as I also used an online SHA512 checksum tool to double-check and it gave me the same hash as the one I got via powershell

If I made a mistake, it would have occurred when converting to byte representation and then back to base64.

It's because you're encoding the hash as ASCII and then converting that encoded hash to Base64. You should just be able to provide hash directly to ToBase64String.

Sephirote said:

Then converted to byte representation

Click to expand...

You're using Asci.GetBytes function insteadof Unicode.GetBytes function

Ok thanks

Hash512 >UTF8 bytes >Base64


Interestingly enough the final hash was really close to the provided base64 hash but not a match

Hash512 >Unicode bytes >Base64


Not a match

The other option suggested is to provide directly the SHA512 hash to ToBase64String but I'm not sure how to do that

@Sephirote
Why don't you just follow the example from SO?

Your screenshot shows you're computing hash value of another hash value rather than hash value of the data.

zebal said:

@Sephirote
Why don't you just follow the example from SO?

Your screenshot shows you're computing hash value of another hash value rather than hash value of the data.

Click to expand...

Sorry but the answers provided aren't really clear/helpful. The issue with you guys is that you assume that you're talking to programmers and skip on the small details/steps that may be obvious to you but not to regular people. I'm not familiar with what Unicode or ASCII is, I try to figure it out as I go with Google but if I'm here asking for help, it didn't cross your mind that I may not be fluent in coding, powershell commands and other hash algorithms. I provided the SHA512, wouldn't have been possible to provide me with the commands instead of unhelpful comments instructing me not to use ASCII but Unicode which I have no clue how to do. I mean you have seen the screenshots, I'm trying to be proactive and to find the solution by myself not just waiting to have the solution mouth fed so give me a break with your silly questions like "why don't you do this or that" Because I don't know how to man.

Never mind I found this site where you input the HEX string and it spits out the base64.

Here's the website for anyone who comes across this thread looking for the same thing, because you sure won't find the solutions in the answers I received

Cheers

@Sephirote
Sorry, maybe you missed it but @glasskuter gave you link to SO (in post #3) which has the example, here is the link:

Does following the example work?

You so far have been doing all just not as shown in the example, that why I said why don't you follow the example from SO.

Could you please provide an example file (link to a small file) that uses base64 encoding for it's hashes so I can download and verify my results in PS?

Nevermind

Here is the full solution that should work:


Result: