+ * caller must free the data inside the structure. The 'type' is one
+ * of following: "silc-rsa", "silc-dss, "ssh-rsa", "ssh-dss",
+ * "pgp-sign-rsa", "pgp-sign-dss", "x509v3-sign-rsa", "x509v3-sign-dss".
+ * See the draft-riikonen-precense-attrs draft for more detailed
+ * information. The 'type' is NULL when this structure includes a
+ * digital signature.
+ *
+ * In SILC, at least the "silc-rsa" must be supported. In this case
+ * the key is normal SILC Public key. To verify a signature with the
+ * SILC Public key, construct the signature data with the
+ * silc_attribute_get_verify_data and verify the signature with
+ * for example silc_pkcs_verify_with_hash function. The public key
+ * to the verification is the `data' and `data_len', and can be decoded
+ * with silc_pkcs_public_key_decode function.