What are private key file formats supported by Gateway?

Here is a list of formats that is supported by Gateway for this case (private key file format):
1) DER - raw data
2) PEM - raw data encoded with base64 (there is a special format of PEM: raw data encoded with base64 that is also encrypted, this one is NOTsupported )
3) PKCS8 - structured data that can be encrypted or not, optionaly encoded with base64

Attention:
Importing a certificate with the private key in an external file that is encrypted with a password is not supported.