PowerShell public & private key hash

powerShellApiKeySigning.ps1

# Thanks to Khuong Phan - duykhuongkid@gmail.com - for providing this example.

# Provided public and private keys
$publicKey = 'xxxxxxxxxxx';
$privateKey = 'yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy';

# Unix timestamp
$unixTime=[int][double]::Parse($(Get-Date -date (Get-Date).ToUniversalTime()-uformat %s))

# Capture the time and package with public key
$package = "$($publicKey)`n$($unixTime)"

# SHA1 hash using the private key and then URL encode the signature
$hmacsha = [System.Security.Cryptography.KeyedHashAlgorithm]::Create("HMACSHA1")
$hmacsha.key = [Text.Encoding]::ASCII.GetBytes($privateKey)

$signature = $hmacsha.ComputeHash([Text.Encoding]::ASCII.GetBytes($package))
$signature = [System.Net.WebUtility]::UrlEncode([Convert]::ToBase64String($signature))

# Create request Url
$requestUri = "?public_key=" + $publicKey + "&time=" + $unixTime + "&signature=" + $signature;
$requestUrl = "https://api.rapidspike.com/v1/assets" + $requestUri;