You can encrypt passwords for your account only using DPAPI. You need the function on this site.

Import the module. On some hardened systems using:

Import-Module '.\Modulename.psm1' -Force

Next encrypt the password using the following command:

$secureString = Read-Host -AsSecureString "Enter a secret password." 

# You can pass basically anything as the Entropy value, but I'd recommend sticking to simple value types (including strings),
# or arrays of those types, to make sure that the binary serialization of your entropy object doesn't change between
# script executions.  Here, we'll use Pi.  Edit:  The latest version of the code enforces the use of the recommended simple
# types, unless you also use the -Force switch.

$secureString | ConvertFrom-SecureString -Entropy ([Math]::PI) | Out-File .\storedPassword.txt

You can use it by decrypting the password as a secure string using the following code:

$newSecureString = Get-Content -Path .\storedPassword.txt | ConvertTo-SecureString -Entropy ([Math]::PI)

You can decrypt the password as plain text using the following code:

$newSecureString = Get-Content -Path .\storedPassword.txt | ConvertTo-SecureString -Entropy ([Math]::PI)
$newSecureString | ConvertFrom-SecureString -AsPlainText -Force