The public key for encryption is located at \Xilinx\Vivado\2017.1\data\pubkey.
In the 2017.1 release, a watermark (string of alphanumeric characters) has been added into the key. This appears as a comment in the key and it is not supposed to be used as a part of the key.
If this watermark is used as part of the key, an error will occur.
The watermark will be removed from the key in the 2017.2 release.
The highlighted watermark should not be used as part of the encryption key.