type_url: "type.googleapis.com/google.crypto.tink.HmacPrfKey"
# value: [type.googleapis.com/google.crypto.tink.HmacPrfKeyFormat] {
#   params {
#     hash: SHA512
#   }
#   key_size: 64
#   version: 0
# }
value: "\n\002\010\004\020@"
output_prefix_type: RAW
