powershell: pipe file content into a command

Question

I'm not fluent into PowerShell, and I struggle on a somewhat simple problem:
I want to encrypt a (small) random file with DPAPI and write the result into another file.

I can encrypt an immediate string:

'cleartext' | ConvertTo-SecureString -AsPlainText -Force | ConvertFrom-SecureString
--> the result is a bunch of digits: 1000000d08c9d[...]0e35854

Same thing, output into a file:

'cleartext' | ConvertTo-SecureString -AsPlainText -Force | ConvertFrom-SecureString | Set-Content -Path output.txt
--> the file is created, and contains the right data

But I don't understand how to get data from a file:

# content of a file
Get-Content -Path input.txt
# --> 1st line
#     blah
#     last line

# pipe it into a command
Get-Content -Path input.txt | Measure-Object -line -word
# --> Lines Words Characters Property
#     ----- ----- ---------- --------
#         3     5

# but can not pipe it into ConvertTo-SecureString
Get-Content -Path input.txt | ConvertTo-SecureString -AsPlainText -Force | ConvertFrom-SecureString
# --> ConvertTo-SecureString : Cannot bind argument to parameter 'String' because it is an empty string. 
#     + ...  -Path input.txt |  ConvertTo-SecureString -AsPlainText -Force | Conve ...
#     +                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#     + CategoryInfo          : InvalidData : (:PSObject) [ConvertTo-SecureString], ParameterBindingValidationException
#     + FullyQualifiedErrorId : ParameterArgumentValidationErrorEmptyStringNotAllowed,Microsoft.PowerShell.Commands.ConvertToSecureStringCommand

Question: how can I make ConvertTo-SecureString to read a file's content?

Answer 1

Thanks to @Santiago Squarzon for the answer: Get-Content by default return an array of strings.
To get the "real" data, the "-raw" parameter must be used.

Get-Content -Path input.txt -Raw | ConvertTo-SecureString -AsPlainText -Force | ConvertFrom-SecureString
# --> 1000000d08c9d[...]0e35854

Answer 2

The issue here is data type mismatch. ConvertTo-SecureString takes String input and not arrays. When in doubt run GetType() method on your object:

'cleartext'.GetType().Name

String

whereas return from vanilla Get-Content is array of objects:

(Get-Content .\input.txt).GetType().Name

Object[]

You don't have to use the Name property but its so much cleaner.

So as proposed in the comments using the " -Raw " switch will give you what you need:

 (Get-Content .\input.txt -Raw).GetType().Name

String