{
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  "docId": "RFC6649",
  "document": {
    "abstract": "The Kerberos 5 network authentication protocol, originally specified in RFC 1510, can use the Data Encryption Standard (DES) for encryption. Almost 30 years after first publishing DES, the National Institute of Standards and Technology (NIST) finally withdrew the standard in 2005, reflecting a long-established consensus that DES is insufficiently secure. By 2008, commercial hardware costing less than USD 15,000 could break DES keys in less than a day on average. DES is long past its sell-by date. Accordingly, this document updates RFC 1964, RFC 4120, RFC 4121, and RFC 4757 to deprecate the use of DES, RC4-HMAC-EXP, and other weak cryptographic algorithms in Kerberos. Because RFC 1510 (obsoleted by RFC 4120) supports only DES, this document recommends the reclassification of RFC 1510 as Historic. This memo documents an Internet Best Current Practice.",
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      "updated": "2026-10-13T22:26:09.310Z",
      "version": "extractDocs.js@commit:fd871efde64d"
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    "authors": [
      {
        "name": "Love Astrand"
      },
      {
        "name": "Taylor Yu"
      }
    ],
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      "confidence": "high",
      "note": "Parsed from Datatracker doc page article:author (profile full names)",
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      "updated": "2026-10-13T22:26:09.310Z",
      "version": "extractDocs.js@commit:fd871efde64d"
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      "confidence": "high",
      "note": "Derived from RFC number or Datatracker identifier",
      "originalValue": null,
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      "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
      "updated": "2026-10-13T22:26:09.310Z",
      "version": "extractDocs.js@commit:fd871efde64d"
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    "docLabel": "IETF RFC 6649",
    "docLabel$meta": {
      "confidence": "high",
      "note": "Constructed from provider and document identifier",
      "originalValue": null,
      "source": "resolved",
      "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
      "updated": "2026-10-13T22:26:09.310Z",
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    "docNumber": "6649",
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      "confidence": "high",
      "note": "Parsed from RFC info page report metadata",
      "originalValue": null,
      "source": "parsed",
      "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
      "updated": "2026-10-13T22:26:09.310Z",
      "version": "extractDocs.js@commit:fd871efde64d"
    },
    "docTitle": "Deprecate DES, RC4-HMAC-EXP, and Other Weak Cryptographic Algorithms in Kerberos",
    "docTitle$meta": {
      "confidence": "high",
      "note": "Parsed from RFC index XML title",
      "originalValue": null,
      "source": "parsed",
      "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
      "updated": "2026-10-13T22:26:09.310Z",
      "version": "extractDocs.js@commit:fd871efde64d"
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    "docType": "Best Practice",
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      "confidence": "high",
      "note": "Mapped from Datatracker std_level or RFC status text",
      "originalValue": null,
      "source": "parsed",
      "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
      "updated": "2026-10-13T22:26:09.310Z",
      "version": "extractDocs.js@commit:fd871efde64d"
    },
    "doi": "10.17487/RFC6649",
    "doi$meta": {
      "confidence": "high",
      "note": "Parsed from RFC index XML doi",
      "originalValue": null,
      "source": "resolved",
      "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
      "updated": "2026-10-13T22:26:09.310Z",
      "version": "extractDocs.js@commit:fd871efde64d"
    },
    "href": "https://doi.org/10.17487/RFC6649",
    "href$meta": {
      "confidence": "high",
      "note": "Derived from DOI (https://doi.org/<doi>)",
      "originalValue": null,
      "source": "resolved",
      "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
      "updated": "2026-10-13T22:26:09.310Z",
      "version": "extractDocs.js@commit:fd871efde64d"
    },
    "pages": "7",
    "pages$meta": {
      "confidence": "high",
      "note": "Parsed from RFC index XML page-count",
      "originalValue": null,
      "source": "parsed",
      "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
      "updated": "2026-10-13T22:26:09.310Z",
      "version": "extractDocs.js@commit:fd871efde64d"
    },
    "publicationDate": "2012-07-01",
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      "confidence": "high",
      "note": "Parsed from RFC index XML date",
      "originalValue": null,
      "source": "parsed",
      "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
      "updated": "2026-10-13T22:26:09.310Z",
      "version": "extractDocs.js@commit:fd871efde64d"
    },
    "publisher": "IETF",
    "publisher$meta": {
      "confidence": "high",
      "note": "Static: provider",
      "originalValue": null,
      "source": "parsed",
      "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
      "updated": "2026-10-13T22:26:09.310Z",
      "version": "extractDocs.js@commit:fd871efde64d"
    },
    "references": {
      "bibliographic": [
        "NIST.FIPS.46-3",
        "RFC1510",
        "RFC4772",
        "orphan/RFC6649/h:09a82c79",
        "orphan/RFC6649/h:caccf1bf",
        "orphan/RFC6649/h:7e76e389",
        "orphan/RFC6649/h:5bbaca8e"
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      "bibliographic$meta": {
        "confidence": "medium",
        "flag": "MIXED_REF_LAYOUT_RISK anchored=14 proseBlocks=16 skippedAnchorBlocks=14",
        "note": "Parsed from RFC HTML references/informative sections",
        "originalValue": [],
        "reviewRequired": true,
        "source": "parsed",
        "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
        "updated": "2026-10-13T22:26:09.310Z",
        "version": "extractDocs.js@commit:fd871efde64d"
      },
      "normative": [
        "RFC1964",
        "RFC2119",
        "RFC3961",
        "RFC4120",
        "RFC4121",
        "RFC4757"
      ],
      "normative$meta": {
        "confidence": "high",
        "note": "Parsed from RFC HTML normative references sections",
        "originalValue": [],
        "source": "parsed",
        "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
        "updated": "2026-10-13T22:26:09.310Z",
        "version": "extractDocs.js@commit:fd871efde64d"
      }
    },
    "resolvedHref": "https://www.rfc-editor.org/info/rfc6649/",
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      "confidence": "high",
      "note": "Final URL resolved via URL redirect verification",
      "originalValue": null,
      "source": "resolved",
      "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
      "updated": "2026-10-13T22:26:09.310Z",
      "version": "extractDocs.js@commit:fd871efde64d"
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    "status": {
      "active": true,
      "active$meta": {
        "confidence": "high",
        "note": "Derived from supersession relationship fields",
        "originalValue": null,
        "source": "resolved",
        "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
        "updated": "2026-10-13T22:26:09.310Z",
        "version": "extractDocs.js@commit:fd871efde64d"
      },
      "amends": [
        "RFC1964",
        "RFC4120",
        "RFC4121",
        "RFC4757"
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      "amends$meta": {
        "confidence": "high",
        "note": "Parsed from RFC index XML",
        "originalValue": [],
        "source": "parsed",
        "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
        "updated": "2026-10-13T22:26:09.310Z",
        "version": "extractDocs.js@commit:fd871efde64d"
      },
      "errataExist": false,
      "errataExist$meta": {
        "confidence": "high",
        "note": "Derived from presence of errata links on RFC/Datatracker pages",
        "originalValue": null,
        "source": "parsed",
        "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
        "updated": "2026-10-13T22:26:09.310Z",
        "version": "extractDocs.js@commit:fd871efde64d"
      },
      "latestVersion": true,
      "latestVersion$meta": {
        "confidence": "high",
        "note": "Derived from supersession relationship fields",
        "originalValue": null,
        "source": "resolved",
        "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
        "updated": "2026-10-13T22:26:09.310Z",
        "version": "extractDocs.js@commit:fd871efde64d"
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      "statusNote": "Best Current Practice",
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        "confidence": "high",
        "note": "Mapped from Datatracker doc.json std_level",
        "originalValue": null,
        "source": "parsed",
        "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
        "updated": "2026-10-13T22:26:09.310Z",
        "version": "extractDocs.js@commit:fd871efde64d"
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      "superseded": false,
      "superseded$meta": {
        "confidence": "high",
        "note": "Derived from supersession relationship fields",
        "originalValue": null,
        "source": "resolved",
        "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
        "updated": "2026-10-13T22:26:09.310Z",
        "version": "extractDocs.js@commit:fd871efde64d"
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        "confidence": "high",
        "note": "Parsed from RFC index XML",
        "originalValue": [],
        "source": "parsed",
        "sourceUrl": "https://www.rfc-editor.org/info/rfc6649/",
        "updated": "2026-10-13T22:26:09.310Z",
        "version": "extractDocs.js@commit:fd871efde64d"
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}