Contains the "phase 2" inner private key when the phase2_auth or phase2_autheap property is set to "tls".
Key data is specified using a "scheme"; two are currently supported: blob and path. When using the blob scheme and private keys, this property should be set to the key's encrypted PEM encoded data. When using private keys with the path scheme, this property should be set to the full UTF-8 encoded path of the key, prefixed with the string "file://" and ending with a terminating NUL byte. When using PKCS#< !-- -->12 format private keys and the blob scheme, this property should be set to the PKCS#<!-- -->12 data and the phase2_private_key_password property must be set to password used to decrypt the PKCS#<!-- -->12 certificate and key. When using PKCS#<!-- -->12 files and the path scheme, this property should be set to the full UTF-8 encoded path of the key, prefixed with the string "file://" and ending with a terminating NUL byte, and as with the blob scheme the phase2_private_key_password property must be set to the password used to decode the PKCS#<!-- -->12 private key and certificate.
Setting this property directly is discouraged; use the set_phase2_private_key function instead.