Why does encrypting HMAC-SHA1 in exactly the same code in C# and PowerShell show different results?
It's because the escape character in PowerShell is ` while the one in C# is \.
$str = "PUT`n`napplication/x-zip-compressed`nThu, 09 Feb 2017 08:59:43 GMT`n/test-bucket/test-key"Should yield the expected result.