1IETF CIPSO Working Group 216 July, 1992 3 4 5 6 COMMERCIAL IP SECURITY OPTION (CIPSO 2.2) 7 8 9 101. Status 11 12This Internet Draft provides the high level specification for a Commercial 13IP Security Option (CIPSO). This draft reflects the version as approved by 14the CIPSO IETF Working Group. Distribution of this memo is unlimited. 15 16This document is an Internet Draft. Internet Drafts are working documents 17of the Internet Engineering Task Force (IETF), its Areas, and its Working 18Groups. Note that other groups may also distribute working documents as 19Internet Drafts. 20 21Internet Drafts are draft documents valid for a maximum of six months. 22Internet Drafts may be updated, replaced, or obsoleted by other documents 23at any time. It is not appropriate to use Internet Drafts as reference 24material or to cite them other than as a "working draft" or "work in 25progress." 26 27Please check the I-D abstract listing contained in each Internet Draft 28directory to learn the current status of this or any other Internet Draft. 29 30 31 32 332. Background 34 35Currently the Internet Protocol includes two security options. One of 36these options is the DoD Basic Security Option (BSO) (Type 130) which allows 37IP datagrams to be labeled with security classifications. This option 38provides sixteen security classifications and a variable number of handling 39restrictions. To handle additional security information, such as security 40categories or compartments, another security option (Type 133) exists and 41is referred to as the DoD Extended Security Option (ESO). The values for 42the fixed fields within these two options are administered by the Defense 43Information Systems Agency (DISA). 44 45Computer vendors are now building commercial operating systems with 46mandatory access controls and multi-level security. These systems are 47no longer built specifically for a particular group in the defense or 48intelligence communities. They are generally available commercial systems 49for use in a variety of government and civil sector environments. 50 51The small number of ESO format codes can not support all the possible 52applications of a commercial security option. The BSO and ESO were 53designed to only support the United States DoD. CIPSO has been designed 54to support multiple security policies. This Internet Draft provides the 55format and procedures required to support a Mandatory Access Control 56security policy. Support for additional security policies shall be 57defined in future RFCs. 58 59 60 61 62Internet Draft, Expires 15 Jan 93 [PAGE 1] 63 64 65 66CIPSO INTERNET DRAFT 16 July, 1992 67 68 69 70 713. CIPSO Format 72 73Option type: 134 (Class 0, Number 6, Copy on Fragmentation) 74Option length: Variable 75 76This option permits security related information to be passed between 77systems within a single Domain of Interpretation (DOI). A DOI is a 78collection of systems which agree on the meaning of particular values 79in the security option. An authority that has been assigned a DOI 80identifier will define a mapping between appropriate CIPSO field values 81and their human readable equivalent. This authority will distribute that 82mapping to hosts within the authority's domain. These mappings may be 83sensitive, therefore a DOI authority is not required to make these 84mappings available to anyone other than the systems that are included in 85the DOI. 86 87This option MUST be copied on fragmentation. This option appears at most 88once in a datagram. All multi-octet fields in the option are defined to be 89transmitted in network byte order. The format of this option is as follows: 90 91+----------+----------+------//------+-----------//---------+ 92| 10000110 | LLLLLLLL | DDDDDDDDDDDD | TTTTTTTTTTTTTTTTTTTT | 93+----------+----------+------//------+-----------//---------+ 94 95 TYPE=134 OPTION DOMAIN OF TAGS 96 LENGTH INTERPRETATION 97 98 99 Figure 1. CIPSO Format 100 101 1023.1 Type 103 104This field is 1 octet in length. Its value is 134. 105 106 1073.2 Length 108 109This field is 1 octet in length. It is the total length of the option 110including the type and length fields. With the current IP header length 111restriction of 40 octets the value of this field MUST not exceed 40. 112 113 1143.3 Domain of Interpretation Identifier 115 116This field is an unsigned 32 bit integer. The value 0 is reserved and MUST 117not appear as the DOI identifier in any CIPSO option. Implementations 118should assume that the DOI identifier field is not aligned on any particular 119byte boundary. 120 121To conserve space in the protocol, security levels and categories are 122represented by numbers rather than their ASCII equivalent. This requires 123a mapping table within CIPSO hosts to map these numbers to their 124corresponding ASCII representations. Non-related groups of systems may 125 126 127 128Internet Draft, Expires 15 Jan 93 [PAGE 2] 129 130 131 132CIPSO INTERNET DRAFT 16 July, 1992 133 134 135 136have their own unique mappings. For example, one group of systems may 137use the number 5 to represent Unclassified while another group may use the 138number 1 to represent that same security level. The DOI identifier is used 139to identify which mapping was used for the values within the option. 140 141 1423.4 Tag Types 143 144A common format for passing security related information is necessary 145for interoperability. CIPSO uses sets of "tags" to contain the security 146information relevant to the data in the IP packet. Each tag begins with 147a tag type identifier followed by the length of the tag and ends with the 148actual security information to be passed. All multi-octet fields in a tag 149are defined to be transmitted in network byte order. Like the DOI 150identifier field in the CIPSO header, implementations should assume that 151all tags, as well as fields within a tag, are not aligned on any particular 152octet boundary. The tag types defined in this document contain alignment 153bytes to assist alignment of some information, however alignment can not 154be guaranteed if CIPSO is not the first IP option. 155 156CIPSO tag types 0 through 127 are reserved for defining standard tag 157formats. Their definitions will be published in RFCs. Tag types whose 158identifiers are greater than 127 are defined by the DOI authority and may 159only be meaningful in certain Domains of Interpretation. For these tag 160types, implementations will require the DOI identifier as well as the tag 161number to determine the security policy and the format associated with the 162tag. Use of tag types above 127 are restricted to closed networks where 163interoperability with other networks will not be an issue. Implementations 164that support a tag type greater than 127 MUST support at least one DOI that 165requires only tag types 1 to 127. 166 167Tag type 0 is reserved. Tag types 1, 2, and 5 are defined in this 168Internet Draft. Types 3 and 4 are reserved for work in progress. 169The standard format for all current and future CIPSO tags is shown below: 170 171+----------+----------+--------//--------+ 172| TTTTTTTT | LLLLLLLL | IIIIIIIIIIIIIIII | 173+----------+----------+--------//--------+ 174 TAG TAG TAG 175 TYPE LENGTH INFORMATION 176 177 Figure 2: Standard Tag Format 178 179In the three tag types described in this document, the length and count 180restrictions are based on the current IP limitation of 40 octets for all 181IP options. If the IP header is later expanded, then the length and count 182restrictions specified in this document may increase to use the full area 183provided for IP options. 184 185 1863.4.1 Tag Type Classes 187 188Tag classes consist of tag types that have common processing requirements 189and support the same security policy. The three tags defined in this 190Internet Draft belong to the Mandatory Access Control (MAC) Sensitivity 191 192 193 194Internet Draft, Expires 15 Jan 93 [PAGE 3] 195 196 197 198CIPSO INTERNET DRAFT 16 July, 1992 199 200 201 202class and support the MAC Sensitivity security policy. 203 204 2053.4.2 Tag Type 1 206 207This is referred to as the "bit-mapped" tag type. Tag type 1 is included 208in the MAC Sensitivity tag type class. The format of this tag type is as 209follows: 210 211+----------+----------+----------+----------+--------//---------+ 212| 00000001 | LLLLLLLL | 00000000 | LLLLLLLL | CCCCCCCCCCCCCCCCC | 213+----------+----------+----------+----------+--------//---------+ 214 215 TAG TAG ALIGNMENT SENSITIVITY BIT MAP OF 216 TYPE LENGTH OCTET LEVEL CATEGORIES 217 218 Figure 3. Tag Type 1 Format 219 220 2213.4.2.1 Tag Type 222 223This field is 1 octet in length and has a value of 1. 224 225 2263.4.2.2 Tag Length 227 228This field is 1 octet in length. It is the total length of the tag type 229including the type and length fields. With the current IP header length 230restriction of 40 bytes the value within this field is between 4 and 34. 231 232 2333.4.2.3 Alignment Octet 234 235This field is 1 octet in length and always has the value of 0. Its purpose 236is to align the category bitmap field on an even octet boundary. This will 237speed many implementations including router implementations. 238 239 2403.4.2.4 Sensitivity Level 241 242This field is 1 octet in length. Its value is from 0 to 255. The values 243are ordered with 0 being the minimum value and 255 representing the maximum 244value. 245 246 2473.4.2.5 Bit Map of Categories 248 249The length of this field is variable and ranges from 0 to 30 octets. This 250provides representation of categories 0 to 239. The ordering of the bits 251is left to right or MSB to LSB. For example category 0 is represented by 252the most significant bit of the first byte and category 15 is represented 253by the least significant bit of the second byte. Figure 4 graphically 254shows this ordering. Bit N is binary 1 if category N is part of the label 255for the datagram, and bit N is binary 0 if category N is not part of the 256label. Except for the optimized tag 1 format described in the next section, 257 258 259 260Internet Draft, Expires 15 Jan 93 [PAGE 4] 261 262 263 264CIPSO INTERNET DRAFT 16 July, 1992 265 266 267 268minimal encoding SHOULD be used resulting in no trailing zero octets in the 269category bitmap. 270 271 octet 0 octet 1 octet 2 octet 3 octet 4 octet 5 272 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX . . . 273bit 01234567 89111111 11112222 22222233 33333333 44444444 274number 012345 67890123 45678901 23456789 01234567 275 276 Figure 4. Ordering of Bits in Tag 1 Bit Map 277 278 2793.4.2.6 Optimized Tag 1 Format 280 281Routers work most efficiently when processing fixed length fields. To 282support these routers there is an optimized form of tag type 1. The format 283does not change. The only change is to the category bitmap which is set to 284a constant length of 10 octets. Trailing octets required to fill out the 10 285octets are zero filled. Ten octets, allowing for 80 categories, was chosen 286because it makes the total length of the CIPSO option 20 octets. If CIPSO 287is the only option then the option will be full word aligned and additional 288filler octets will not be required. 289 290 2913.4.3 Tag Type 2 292 293This is referred to as the "enumerated" tag type. It is used to describe 294large but sparsely populated sets of categories. Tag type 2 is in the MAC 295Sensitivity tag type class. The format of this tag type is as follows: 296 297+----------+----------+----------+----------+-------------//-------------+ 298| 00000010 | LLLLLLLL | 00000000 | LLLLLLLL | CCCCCCCCCCCCCCCCCCCCCCCCCC | 299+----------+----------+----------+----------+-------------//-------------+ 300 301 TAG TAG ALIGNMENT SENSITIVITY ENUMERATED 302 TYPE LENGTH OCTET LEVEL CATEGORIES 303 304 Figure 5. Tag Type 2 Format 305 306 3073.4.3.1 Tag Type 308 309This field is one octet in length and has a value of 2. 310 311 3123.4.3.2 Tag Length 313 314This field is 1 octet in length. It is the total length of the tag type 315including the type and length fields. With the current IP header length 316restriction of 40 bytes the value within this field is between 4 and 34. 317 318 3193.4.3.3 Alignment Octet 320 321This field is 1 octet in length and always has the value of 0. Its purpose 322is to align the category field on an even octet boundary. This will 323 324 325 326Internet Draft, Expires 15 Jan 93 [PAGE 5] 327 328 329 330CIPSO INTERNET DRAFT 16 July, 1992 331 332 333 334speed many implementations including router implementations. 335 336 3373.4.3.4 Sensitivity Level 338 339This field is 1 octet in length. Its value is from 0 to 255. The values 340are ordered with 0 being the minimum value and 255 representing the 341maximum value. 342 343 3443.4.3.5 Enumerated Categories 345 346In this tag, categories are represented by their actual value rather than 347by their position within a bit field. The length of each category is 2 348octets. Up to 15 categories may be represented by this tag. Valid values 349for categories are 0 to 65534. Category 65535 is not a valid category 350value. The categories MUST be listed in ascending order within the tag. 351 352 3533.4.4 Tag Type 5 354 355This is referred to as the "range" tag type. It is used to represent 356labels where all categories in a range, or set of ranges, are included 357in the sensitivity label. Tag type 5 is in the MAC Sensitivity tag type 358class. The format of this tag type is as follows: 359 360+----------+----------+----------+----------+------------//-------------+ 361| 00000101 | LLLLLLLL | 00000000 | LLLLLLLL | Top/Bottom | Top/Bottom | 362+----------+----------+----------+----------+------------//-------------+ 363 364 TAG TAG ALIGNMENT SENSITIVITY CATEGORY RANGES 365 TYPE LENGTH OCTET LEVEL 366 367 Figure 6. Tag Type 5 Format 368 369 3703.4.4.1 Tag Type 371 372This field is one octet in length and has a value of 5. 373 374 3753.4.4.2 Tag Length 376 377This field is 1 octet in length. It is the total length of the tag type 378including the type and length fields. With the current IP header length 379restriction of 40 bytes the value within this field is between 4 and 34. 380 381 3823.4.4.3 Alignment Octet 383 384This field is 1 octet in length and always has the value of 0. Its purpose 385is to align the category range field on an even octet boundary. This will 386speed many implementations including router implementations. 387 388 389 390 391 392Internet Draft, Expires 15 Jan 93 [PAGE 6] 393 394 395 396CIPSO INTERNET DRAFT 16 July, 1992 397 398 399 4003.4.4.4 Sensitivity Level 401 402This field is 1 octet in length. Its value is from 0 to 255. The values 403are ordered with 0 being the minimum value and 255 representing the maximum 404value. 405 406 4073.4.4.5 Category Ranges 408 409A category range is a 4 octet field comprised of the 2 octet index of the 410highest numbered category followed by the 2 octet index of the lowest 411numbered category. These range endpoints are inclusive within the range of 412categories. All categories within a range are included in the sensitivity 413label. This tag may contain a maximum of 7 category pairs. The bottom 414category endpoint for the last pair in the tag MAY be omitted and SHOULD be 415assumed to be 0. The ranges MUST be non-overlapping and be listed in 416descending order. Valid values for categories are 0 to 65534. Category 41765535 is not a valid category value. 418 419 4203.4.5 Minimum Requirements 421 422A CIPSO implementation MUST be capable of generating at least tag type 1 in 423the non-optimized form. In addition, a CIPSO implementation MUST be able 424to receive any valid tag type 1 even those using the optimized tag type 1 425format. 426 427 4284. Configuration Parameters 429 430The configuration parameters defined below are required for all CIPSO hosts, 431gateways, and routers that support multiple sensitivity labels. A CIPSO 432host is defined to be the origination or destination system for an IP 433datagram. A CIPSO gateway provides IP routing services between two or more 434IP networks and may be required to perform label translations between 435networks. A CIPSO gateway may be an enhanced CIPSO host or it may just 436provide gateway services with no end system CIPSO capabilities. A CIPSO 437router is a dedicated IP router that routes IP datagrams between two or more 438IP networks. 439 440An implementation of CIPSO on a host MUST have the capability to reject a 441datagram for reasons that the information contained can not be adequately 442protected by the receiving host or if acceptance may result in violation of 443the host or network security policy. In addition, a CIPSO gateway or router 444MUST be able to reject datagrams going to networks that can not provide 445adequate protection or may violate the network's security policy. To 446provide this capability the following minimal set of configuration 447parameters are required for CIPSO implementations: 448 449HOST_LABEL_MAX - This parameter contains the maximum sensitivity label that 450a CIPSO host is authorized to handle. All datagrams that have a label 451greater than this maximum MUST be rejected by the CIPSO host. This 452parameter does not apply to CIPSO gateways or routers. This parameter need 453not be defined explicitly as it can be implicitly derived from the 454PORT_LABEL_MAX parameters for the associated interfaces. 455 456 457 458Internet Draft, Expires 15 Jan 93 [PAGE 7] 459 460 461 462CIPSO INTERNET DRAFT 16 July, 1992 463 464 465 466 467HOST_LABEL_MIN - This parameter contains the minimum sensitivity label that 468a CIPSO host is authorized to handle. All datagrams that have a label less 469than this minimum MUST be rejected by the CIPSO host. This parameter does 470not apply to CIPSO gateways or routers. This parameter need not be defined 471explicitly as it can be implicitly derived from the PORT_LABEL_MIN 472parameters for the associated interfaces. 473 474PORT_LABEL_MAX - This parameter contains the maximum sensitivity label for 475all datagrams that may exit a particular network interface port. All 476outgoing datagrams that have a label greater than this maximum MUST be 477rejected by the CIPSO system. The label within this parameter MUST be 478less than or equal to the label within the HOST_LABEL_MAX parameter. This 479parameter does not apply to CIPSO hosts that support only one network port. 480 481PORT_LABEL_MIN - This parameter contains the minimum sensitivity label for 482all datagrams that may exit a particular network interface port. All 483outgoing datagrams that have a label less than this minimum MUST be 484rejected by the CIPSO system. The label within this parameter MUST be 485greater than or equal to the label within the HOST_LABEL_MIN parameter. 486This parameter does not apply to CIPSO hosts that support only one network 487port. 488 489PORT_DOI - This parameter is used to assign a DOI identifier value to a 490particular network interface port. All CIPSO labels within datagrams 491going out this port MUST use the specified DOI identifier. All CIPSO 492hosts and gateways MUST support either this parameter, the NET_DOI 493parameter, or the HOST_DOI parameter. 494 495NET_DOI - This parameter is used to assign a DOI identifier value to a 496particular IP network address. All CIPSO labels within datagrams destined 497for the particular IP network MUST use the specified DOI identifier. All 498CIPSO hosts and gateways MUST support either this parameter, the PORT_DOI 499parameter, or the HOST_DOI parameter. 500 501HOST_DOI - This parameter is used to assign a DOI identifier value to a 502particular IP host address. All CIPSO labels within datagrams destined for 503the particular IP host will use the specified DOI identifier. All CIPSO 504hosts and gateways MUST support either this parameter, the PORT_DOI 505parameter, or the NET_DOI parameter. 506 507This list represents the minimal set of configuration parameters required 508to be compliant. Implementors are encouraged to add to this list to 509provide enhanced functionality and control. For example, many security 510policies may require both incoming and outgoing datagrams be checked against 511the port and host label ranges. 512 513 5144.1 Port Range Parameters 515 516The labels represented by the PORT_LABEL_MAX and PORT_LABEL_MIN parameters 517MAY be in CIPSO or local format. Some CIPSO systems, such as routers, may 518want to have the range parameters expressed in CIPSO format so that incoming 519labels do not have to be converted to a local format before being compared 520against the range. If multiple DOIs are supported by one of these CIPSO 521 522 523 524Internet Draft, Expires 15 Jan 93 [PAGE 8] 525 526 527 528CIPSO INTERNET DRAFT 16 July, 1992 529 530 531 532systems then multiple port range parameters would be needed, one set for 533each DOI supported on a particular port. 534 535The port range will usually represent the total set of labels that may 536exist on the logical network accessed through the corresponding network 537interface. It may, however, represent a subset of these labels that are 538allowed to enter the CIPSO system. 539 540 5414.2 Single Label CIPSO Hosts 542 543CIPSO implementations that support only one label are not required to 544support the parameters described above. These limited implementations are 545only required to support a NET_LABEL parameter. This parameter contains 546the CIPSO label that may be inserted in datagrams that exit the host. In 547addition, the host MUST reject any incoming datagram that has a label which 548is not equivalent to the NET_LABEL parameter. 549 550 5515. Handling Procedures 552 553This section describes the processing requirements for incoming and 554outgoing IP datagrams. Just providing the correct CIPSO label format 555is not enough. Assumptions will be made by one system on how a 556receiving system will handle the CIPSO label. Wrong assumptions may 557lead to non-interoperability or even a security incident. The 558requirements described below represent the minimal set needed for 559interoperability and that provide users some level of confidence. 560Many other requirements could be added to increase user confidence, 561however at the risk of restricting creativity and limiting vendor 562participation. 563 564 5655.1 Input Procedures 566 567All datagrams received through a network port MUST have a security label 568associated with them, either contained in the datagram or assigned to the 569receiving port. Without this label the host, gateway, or router will not 570have the information it needs to make security decisions. This security 571label will be obtained from the CIPSO if the option is present in the 572datagram. See section 4.1.2 for handling procedures for unlabeled 573datagrams. This label will be compared against the PORT (if appropriate) 574and HOST configuration parameters defined in section 3. 575 576If any field within the CIPSO option, such as the DOI identifier, is not 577recognized the IP datagram is discarded and an ICMP "parameter problem" 578(type 12) is generated and returned. The ICMP code field is set to "bad 579parameter" (code 0) and the pointer is set to the start of the CIPSO field 580that is unrecognized. 581 582If the contents of the CIPSO are valid but the security label is 583outside of the configured host or port label range, the datagram is 584discarded and an ICMP "destination unreachable" (type 3) is generated 585and returned. The code field of the ICMP is set to "communication with 586destination network administratively prohibited" (code 9) or to 587 588 589 590Internet Draft, Expires 15 Jan 93 [PAGE 9] 591 592 593 594CIPSO INTERNET DRAFT 16 July, 1992 595 596 597 598"communication with destination host administratively prohibited" 599(code 10). The value of the code field used is dependent upon whether 600the originator of the ICMP message is acting as a CIPSO host or a CIPSO 601gateway. The recipient of the ICMP message MUST be able to handle either 602value. The same procedure is performed if a CIPSO can not be added to an 603IP packet because it is too large to fit in the IP options area. 604 605If the error is triggered by receipt of an ICMP message, the message 606is discarded and no response is permitted (consistent with general ICMP 607processing rules). 608 609 6105.1.1 Unrecognized tag types 611 612The default condition for any CIPSO implementation is that an 613unrecognized tag type MUST be treated as a "parameter problem" and 614handled as described in section 4.1. A CIPSO implementation MAY allow 615the system administrator to identify tag types that may safely be 616ignored. This capability is an allowable enhancement, not a 617requirement. 618 619 6205.1.2 Unlabeled Packets 621 622A network port may be configured to not require a CIPSO label for all 623incoming datagrams. For this configuration a CIPSO label must be 624assigned to that network port and associated with all unlabeled IP 625datagrams. This capability might be used for single level networks or 626networks that have CIPSO and non-CIPSO hosts and the non-CIPSO hosts 627all operate at the same label. 628 629If a CIPSO option is required and none is found, the datagram is 630discarded and an ICMP "parameter problem" (type 12) is generated and 631returned to the originator of the datagram. The code field of the ICMP 632is set to "option missing" (code 1) and the ICMP pointer is set to 134 633(the value of the option type for the missing CIPSO option). 634 635 6365.2 Output Procedures 637 638A CIPSO option MUST appear only once in a datagram. Only one tag type 639from the MAC Sensitivity class MAY be included in a CIPSO option. Given 640the current set of defined tag types, this means that CIPSO labels at 641first will contain only one tag. 642 643All datagrams leaving a CIPSO system MUST meet the following condition: 644 645 PORT_LABEL_MIN <= CIPSO label <= PORT_LABEL_MAX 646 647If this condition is not satisfied the datagram MUST be discarded. 648If the CIPSO system only supports one port, the HOST_LABEL_MIN and the 649HOST_LABEL_MAX parameters MAY be substituted for the PORT parameters in 650the above condition. 651 652The DOI identifier to be used for all outgoing datagrams is configured by 653 654 655 656Internet Draft, Expires 15 Jan 93 [PAGE 10] 657 658 659 660CIPSO INTERNET DRAFT 16 July, 1992 661 662 663 664the administrator. If port level DOI identifier assignment is used, then 665the PORT_DOI configuration parameter MUST contain the DOI identifier to 666use. If network level DOI assignment is used, then the NET_DOI parameter 667MUST contain the DOI identifier to use. And if host level DOI assignment 668is employed, then the HOST_DOI parameter MUST contain the DOI identifier 669to use. A CIPSO implementation need only support one level of DOI 670assignment. 671 672 6735.3 DOI Processing Requirements 674 675A CIPSO implementation MUST support at least one DOI and SHOULD support 676multiple DOIs. System and network administrators are cautioned to 677ensure that at least one DOI is common within an IP network to allow for 678broadcasting of IP datagrams. 679 680CIPSO gateways MUST be capable of translating a CIPSO option from one 681DOI to another when forwarding datagrams between networks. For 682efficiency purposes this capability is only a desired feature for CIPSO 683routers. 684 685 6865.4 Label of ICMP Messages 687 688The CIPSO label to be used on all outgoing ICMP messages MUST be equivalent 689to the label of the datagram that caused the ICMP message. If the ICMP was 690generated due to a problem associated with the original CIPSO label then the 691following responses are allowed: 692 693 a. Use the CIPSO label of the original IP datagram 694 b. Drop the original datagram with no return message generated 695 696In most cases these options will have the same effect. If you can not 697interpret the label or if it is outside the label range of your host or 698interface then an ICMP message with the same label will probably not be 699able to exit the system. 700 701 7026. Assignment of DOI Identifier Numbers = 703 704Requests for assignment of a DOI identifier number should be addressed to 705the Internet Assigned Numbers Authority (IANA). 706 707 7087. Acknowledgements 709 710Much of the material in this RFC is based on (and copied from) work 711done by Gary Winiger of Sun Microsystems and published as Commercial 712IP Security Option at the INTEROP 89, Commercial IPSO Workshop. 713 714 7158. Author's Address 716 717To submit mail for distribution to members of the IETF CIPSO Working 718Group, send mail to: cipso@wdl1.wdl.loral.com. 719 720 721 722Internet Draft, Expires 15 Jan 93 [PAGE 11] 723 724 725 726CIPSO INTERNET DRAFT 16 July, 1992 727 728 729 730 731To be added to or deleted from this distribution, send mail to: 732cipso-request@wdl1.wdl.loral.com. 733 734 7359. References 736 737RFC 1038, "Draft Revised IP Security Option", M. St. Johns, IETF, January 7381988. 739 740RFC 1108, "U.S. Department of Defense Security Options 741for the Internet Protocol", Stephen Kent, IAB, 1 March, 1991. 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788Internet Draft, Expires 15 Jan 93 [PAGE 12] 789 790 791 792