module ietf-keystore {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-keystore";
  prefix ks;

  import ietf-netconf-acm {
    prefix nacm;
    reference
      "RFC 8341: Network Configuration Access Control Model";
  }

  import ietf-crypto-types {
    prefix ct;
    reference
      "RFC AAAA: YANG Data Types and Groupings for Cryptography";
  }

  organization
    "IETF NETCONF (Network Configuration) Working Group";

  contact
    "WG Web:   https://datatracker.ietf.org/wg/netconf
     WG List:  NETCONF WG list <mailto:netconf@ietf.org>
     Author:   Kent Watsen <mailto:kent+ietf@watsen.net>";

  description
    "This module defines a 'keystore' to centralize management
     of security credentials.

     Copyright (c) 2023 IETF Trust and the persons identified
     as authors of the code. All rights reserved.

     Redistribution and use in source and binary forms, with
     or without modification, is permitted pursuant to, and
     subject to the license terms contained in, the Revised
     BSD License set forth in Section 4.c of the IETF Trust's
     Legal Provisions Relating to IETF Documents
     (https://trustee.ietf.org/license-info).

     This version of this YANG module is part of RFC CCCC
     (https://www.rfc-editor.org/info/rfcCCCC); see the RFC
     itself for full legal notices.

     The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL',
     'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED',
     'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this document
     are to be interpreted as described in BCP 14 (RFC 2119)
     (RFC 8174) when, and only when, they appear in all
     capitals, as shown here.";

  revision 2023-04-17 {
    description
      "Initial version";
    reference
      "RFC CCCC: A YANG Data Model for a Keystore";
  }

  /****************/
  /*   Features   */
  /****************/

  feature central-keystore-supported {
    description
      "The 'central-keystore-supported' feature indicates that
       the server supports the keystore (i.e., implements the
       'ietf-keystore' module).";
  }

  feature inline-definitions-supported {
    description
      "The 'inline-definitions-supported' feature indicates that
       the server supports locally-defined keys.";
  }

  feature asymmetric-keys {
    description
      "The 'asymmetric-keys' feature indicates that the server
       implements the /keystore/asymmetric-keys subtree.";

  }

  feature symmetric-keys {
    description
      "The 'symmetric-keys' feature indicates that the server
       implements the /keystore/symmetric-keys subtree.";
  }

  /****************/
  /*   Typedefs   */
  /****************/

  typedef symmetric-key-ref {
    type leafref {
      path "/ks:keystore/ks:symmetric-keys/ks:symmetric-key"
         + "/ks:name";
    }
    description
      "This typedef enables modules to easily define a reference
       to a symmetric key stored in the keystore, when this
       module is implemented.";
  }

  typedef asymmetric-key-ref {
    type leafref {
      path "/ks:keystore/ks:asymmetric-keys/ks:asymmetric-key"
         + "/ks:name";
    }
    description
      "This typedef enables modules to easily define a reference
       to an asymmetric key stored in the keystore, when this
       module is implemented.";
  }

  /*****************/
  /*   Groupings   */
  /*****************/

  grouping encrypted-by-choice-grouping {
    description
      "A grouping that defines a 'choice' statement that can be
       augmented into the 'encrypted-by' node, present in the
       'symmetric-key-grouping' and 'asymmetric-key-pair-grouping'
       groupings defined in RFC AAAA, enabling references to keys
       in the keystore, when this module is implemented.";
    choice encrypted-by-choice {
      nacm:default-deny-write;
      mandatory true;
      description
        "A choice amongst other symmetric or asymmetric keys.";
      case symmetric-key-ref {
        if-feature "central-keystore-supported";
        if-feature "symmetric-keys";
        leaf symmetric-key-ref {
          type ks:symmetric-key-ref;
          description
            "Identifies the symmetric key used to encrypt the
             associated key.";
        }
      }
      case asymmetric-key-ref {
        if-feature "central-keystore-supported";
        if-feature "asymmetric-keys";
        leaf asymmetric-key-ref {
          type ks:asymmetric-key-ref;
          description
            "Identifies the asymmetric key whose public key
             encrypted the associated key.";
        }
      }
    }
  }

  grouping asymmetric-key-certificate-ref-grouping {
    description
      "This grouping defines a reference to a specific certificate
       associated with an asymmetric key stored in the keystore,
       when this module is implemented.";
    leaf asymmetric-key {
      nacm:default-deny-write;
      if-feature "central-keystore-supported";
      if-feature "asymmetric-keys";
      type ks:asymmetric-key-ref;
      must '../certificate';
      description
        "A reference to an asymmetric key in the keystore.";
    }
    leaf certificate {
      nacm:default-deny-write;
      type leafref {
        path "/ks:keystore/ks:asymmetric-keys/ks:asymmetric-key"
           + "[ks:name = current()/../asymmetric-key]/"
           + "ks:certificates/ks:certificate/ks:name";
      }
      must '../asymmetric-key';
      description
        "A reference to a specific certificate of the
         asymmetric key in the keystore.";
    }
  }

  // inline-or-keystore-* groupings

  grouping inline-or-keystore-symmetric-key-grouping {
    description
      "A grouping that expands to allow the symmetric key to be
       either stored locally, i.e., within the using data model,
       or a reference to a symmetric key stored in the keystore.

       Servers that do not 'implement' this module, and hence
       'central-keystore-supported' is not defined, SHOULD
       augment in custom 'case' statements enabling references
       to the alternate keystore locations.";
    choice inline-or-keystore {
      nacm:default-deny-write;
      mandatory true;
      description
        "A choice between an inlined definition and a definition
         that exists in the keystore.";
      case inline {
        if-feature "inline-definitions-supported";
        container inline-definition {
          description
            "Container to hold the local key definition.";
          uses ct:symmetric-key-grouping;
        }
      }
      case keystore {
        if-feature "central-keystore-supported";
        if-feature "symmetric-keys";
        leaf keystore-reference {
          type ks:symmetric-key-ref;
          description
            "A reference to an symmetric key that exists in
             the keystore, when this module is implemented.";
        }
      }
    }
  }

  grouping inline-or-keystore-asymmetric-key-grouping {
    description
      "A grouping that expands to allow the asymmetric key to be
       either stored locally, i.e., within the using data model,
       or a reference to an asymmetric key stored in the keystore.

       Servers that do not 'implement' this module, and hence
       'central-keystore-supported' is not defined, SHOULD
       augment in custom 'case' statements enabling references
       to the alternate keystore locations.";
    choice inline-or-keystore {
      nacm:default-deny-write;
      mandatory true;
      description
        "A choice between an inlined definition and a definition
         that exists in the keystore.";
      case inline {
        if-feature "inline-definitions-supported";
        container inline-definition {
          description
            "Container to hold the local key definition.";
          uses ct:asymmetric-key-pair-grouping;
        }
      }
      case keystore {
        if-feature "central-keystore-supported";
        if-feature "asymmetric-keys";
        leaf keystore-reference {
          type ks:asymmetric-key-ref;
          description
            "A reference to an asymmetric key that exists in
             the keystore, when this module is implemented.  The
             intent is to reference just the asymmetric key
             without any regard for any certificates that may
             be associated with it.";
        }
      }
    }
  }

  grouping inline-or-keystore-asymmetric-key-with-certs-grouping {
    description
      "A grouping that expands to allow an asymmetric key and
       its associated certificates to be either stored locally,
       i.e., within the using data model, or a reference to an
       asymmetric key (and its associated certificates) stored
       in the keystore.

       Servers that do not 'implement' this module, and hence
       'central-keystore-supported' is not defined, SHOULD
       augment in custom 'case' statements enabling references
       to the alternate keystore locations.";
    choice inline-or-keystore {
      nacm:default-deny-write;
      mandatory true;
      description
        "A choice between an inlined definition and a definition
         that exists in the keystore.";
      case inline {
        if-feature "inline-definitions-supported";
        container inline-definition {
          description
            "Container to hold the local key definition.";
          uses ct:asymmetric-key-pair-with-certs-grouping;
        }
      }
      case keystore {
        if-feature "central-keystore-supported";
        if-feature "asymmetric-keys";
        leaf keystore-reference {
          type ks:asymmetric-key-ref;
          description
            "A reference to an asymmetric-key (and all of its
             associated certificates) in the keystore, when
             this module is implemented.";
        }
      }
    }
  }

  grouping inline-or-keystore-end-entity-cert-with-key-grouping {
    description
      "A grouping that expands to allow an end-entity certificate
       (and its associated asymmetric key pair) to be either stored
       locally, i.e., within the using data model, or a reference
       to a specific certificate in the keystore.

       Servers that do not 'implement' this module, and hence
       'central-keystore-supported' is not defined, SHOULD
       augment in custom 'case' statements enabling references
       to the alternate keystore locations.";
    choice inline-or-keystore {
      nacm:default-deny-write;
      mandatory true;
      description
        "A choice between an inlined definition and a definition
         that exists in the keystore.";
      case inline {
        if-feature "inline-definitions-supported";
        container inline-definition {
          description
            "Container to hold the local key definition.";
          uses ct:asymmetric-key-pair-with-cert-grouping;
        }
      }
      case keystore {
        if-feature "central-keystore-supported";
        if-feature "asymmetric-keys";
        container keystore-reference {
          uses asymmetric-key-certificate-ref-grouping;
          description
            "A reference to a specific certificate associated with
             an asymmetric key stored in the keystore, when this
             module is implemented.";
        }
      }
    }
  }

  grouping keystore-grouping {
    description
      "Grouping definition enables use in other contexts.  If ever
       done, implementations MUST augment new 'case' statements
       into the various inline-or-keystore 'choice' statements to
       supply leafrefs to the model-specific location(s).";
    container asymmetric-keys {
      nacm:default-deny-write;
      if-feature "asymmetric-keys";
      description
        "A list of asymmetric keys.";
      list asymmetric-key {
        key "name";
        description
          "An asymmetric key.";
        leaf name {
          type string;
          description
            "An arbitrary name for the asymmetric key.";
        }
        uses ct:asymmetric-key-pair-with-certs-grouping;
      }
    }
    container symmetric-keys {
      nacm:default-deny-write;
      if-feature "symmetric-keys";
      description
        "A list of symmetric keys.";
      list symmetric-key {
        key "name";
        description
          "A symmetric key.";
        leaf name {
          type string;
          description
            "An arbitrary name for the symmetric key.";
        }
        uses ct:symmetric-key-grouping;
      }
    }
  }

  /*********************************/
  /*   Protocol accessible nodes   */
  /*********************************/

  container keystore {
    if-feature central-keystore-supported;
    description
      "A central keystore containing a list of symmetric keys and
       a list of asymmetric keys.";
    nacm:default-deny-write;
    uses keystore-grouping {
      augment "symmetric-keys/symmetric-key/key-type/encrypted-key/"
            + "encrypted-key/encrypted-by" {
        description
          "Augments in a choice statement enabling the encrypting
           key to be any other symmetric or asymmetric key in the
           central keystore.";
        uses encrypted-by-choice-grouping;
      }
      augment "asymmetric-keys/asymmetric-key/private-key-type/"
            + "encrypted-private-key/encrypted-private-key/"
            + "encrypted-by" {
        description
          "Augments in a choice statement enabling the encrypting
           key to be any other symmetric or asymmetric key in the
           central keystore.";
        uses encrypted-by-choice-grouping;
      }
    }
  }
}