Use this data source to access the attributes of an SSH Key.
data "opc_compute_ssh_key" "test" {
  name    = "/Compute-${var.domain}/${var.user}/test-key"
}
output "public_ssh_key" {
  value = "${data.opc_compute_ssh_key.test.key}"
}
name - (Required) The unique (within this identity domain) name of the SSH key. 
    © 2018 HashiCorpLicensed under the MPL 2.0 License.
    https://www.terraform.io/docs/providers/opc/d/opc_compute_ssh_key.html