-f, --format:

Format selection for the public key output file. 'tss' (the default) will output a binary blob according to the TPM 2.0 Specification. 'pem' will output an OpenSSL compatible PEM encoded public key. 'der' will output an OpenSSL compatible DER encoded public key. 'tpmt' will output a binary blob of the TPMT_PUBLIC struct referenced by TPM 2.0 specs.