AES encryption with Protect/Unprotect-CString adds null bytes to decrypted string

[decoyjoe]

When encrypting and then decrypting a string with Protect-CString/Unprotect-CString via a -Key (i.e. AES encryption), the resulting decrypted string contains null bytes at the end.

Current behavior:

> $key = '1' * 16
> $result = 'a' | Protect-CString -Key $key | Unprotect-CString -Key $key
> $result.length
16
> [System.Text.Encoding]::UTF8.GetBytes($result)
97
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

Expected behavior:

> $key = '1' * 16
> $result = 'a' | Protect-CString -Key $key | Unprotect-CString -Key $key
> $result.length
1
> [System.Text.Encoding]::UTF8.GetBytes($result)
97