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 9640: 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.

     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.

     Copyright (c) 2024 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 9642
     (https://www.rfc-editor.org/info/rfc9642); see the RFC
     itself for full legal notices.";

  revision 2024-10-10 {
    description
      "Initial version";
    reference
      "RFC 9642: A YANG Data Model for a Keystore";
  }

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

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

  typedef central-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 central keystore.";
  }

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

  grouping encrypted-by-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 9640, enabling references to keys
       in the central keystore.";
    choice encrypted-by {
      nacm:default-deny-write;
      mandatory true;
      description
        "A choice amongst other symmetric or asymmetric keys.";
      case central-symmetric-key-ref {
        if-feature "central-keystore-supported";
        if-feature "symmetric-keys";
        leaf symmetric-key-ref {
          type ks:central-symmetric-key-ref;
          description
            "Identifies the symmetric key used to encrypt the
             associated key.";
        }
      }
      case central-asymmetric-key-ref {
        if-feature "central-keystore-supported";
        if-feature "asymmetric-keys";
        leaf asymmetric-key-ref {
          type ks:central-asymmetric-key-ref;
          description
            "Identifies the asymmetric key whose public key
             encrypted the associated key.";
        }
      }
    }
  }

  // *-ref groupings

  grouping central-asymmetric-key-certificate-ref-grouping {
    description
      "A grouping for the reference to a certificate associated
       with an asymmetric key stored in the central keystore.";
    leaf asymmetric-key {
      nacm:default-deny-write;
      if-feature "central-keystore-supported";
      if-feature "asymmetric-keys";
      type ks:central-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 for the configuration of a symmetric key.  The
       symmetric key may be defined inline or as a reference to
       a symmetric key stored in the central keystore.

       Servers that wish to define alternate keystore locations
       SHOULD augment in custom 'case' statements enabling
       references to those 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
            "A container to hold the local key definition.";
          uses ct:symmetric-key-grouping;
        }
      }
      case central-keystore {
        if-feature "central-keystore-supported";
        if-feature "symmetric-keys";
        leaf central-keystore-reference {
          type ks:central-symmetric-key-ref;
          description
            "A reference to a symmetric key that exists in
             the central keystore.";
        }
      }
    }
  }

  grouping inline-or-keystore-asymmetric-key-grouping {
    description
      "A grouping for the configuration of an asymmetric key.  The
       asymmetric key may be defined inline or as a reference to
       an asymmetric key stored in the central keystore.

       Servers that wish to define alternate keystore locations
       SHOULD augment in custom 'case' statements enabling
       references to those 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
            "A container to hold the local key definition.";
          uses ct:asymmetric-key-pair-grouping;
        }
      }
      case central-keystore {
        if-feature "central-keystore-supported";
        if-feature "asymmetric-keys";
        leaf central-keystore-reference {
          type ks:central-asymmetric-key-ref;
          description
            "A reference to an asymmetric key that exists in
             the central keystore.  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 for the configuration of an asymmetric key and
       its associated certificates.  The asymmetric key and its
       associated certificates may be defined inline or as a
       reference to an asymmetric key (and its associated
       certificates) in the central keystore.

       Servers that wish to define alternate keystore locations
       SHOULD augment in custom 'case' statements enabling
       references to those 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
            "A container to hold the local key definition.";
          uses ct:asymmetric-key-pair-with-certs-grouping;
        }
      }
      case central-keystore {
        if-feature "central-keystore-supported";
        if-feature "asymmetric-keys";
        leaf central-keystore-reference {
          type ks:central-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 for the configuration of an asymmetric key and
       its associated end-entity certificate.  The asymmetric key
       and its associated end-entity certificate may be defined
       inline or as a reference to an asymmetric key (and its
       associated end-entity certificate) in the central keystore.

       Servers that wish to define alternate keystore locations
       SHOULD augment in custom 'case' statements enabling
       references to those 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
            "A container to hold the local key definition.";
          uses ct:asymmetric-key-pair-with-cert-grouping;
        }
      }
      case central-keystore {
        if-feature "central-keystore-supported";
        if-feature "asymmetric-keys";
        container central-keystore-reference {
          uses central-asymmetric-key-certificate-ref-grouping;
          description
            "A reference to a specific certificate associated with
             an asymmetric key stored in the central keystore.";
        }
      }
    }
  }

  // the keystore grouping

  grouping keystore-grouping {
    description
      "A 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-"
            + "symmetric-key/encrypted-symmetric-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-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-grouping;
      }
    }
  }
}