This OCTET STRING, up to 255 bytes and with no further source description, holds a key value associated with this IKE Crypto Map, consistent with its name identifying it as the map's pre-shared or similar cryptographic key material. An admin sets this to the shared secret both this device and its IKE peer must present during phase 1 authentication, so any mismatch here prevents the tunnel from ever establishing. For example, an admin establishing a new IKE crypto map to a partner gateway would enter the exact pre-shared key value agreed with that partner's administrator.