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The String Similarity Evaluation (SSE) evaluates top-level domains to prevent user confusion and loss of confidence in the Domain Name System (DNS) that would result from delegation of visually similar strings in the root zone.
The SSE is required as a part of the New gTLD Program: 2026 Round application evaluation as per the details found in the New gTLD Program: 2026 Round Applicant Guidebook (AGB), Section 7.10. This is based on the Generic Names Supporting Organization (GNSO) Final Report on the New gTLD Subsequent Procedures Policy Development Process (Section 24) and the Phase 1 Final Report on the Internationalized Domain Names Expedited Policy Development Process.
The SSE is conducted by analyzing comparisons between strings along with their variant strings. This is accomplished through a manual review process based on the pre-screening report generated by the SSE tool using the SSE data, and following the SSE guidelines.
SSE guidelines: String Similarity Evaluation Guidelines for the New gTLD Program: 2026 Round version 1.0
The SSE guidelines will provide direction for the SSE panel on how to manually conduct the string similarity evaluation and how to use the pre-screening report generated by the SSE tool during this analysis. The SSE guidelines have been finalized after public comment.
The SSE data identifies the pairs of code points which are similar, as determined by script experts, and defines the level of similarity between them. The SSE data covers the analysis of the full repertoire of the Root Zone Label Generation Rules (RZ-LGR). The SSE data is tabulated in a machine-readable XML version, intended to be used by the SSE tool, and in a human-readable HTML version.
For details, see the overview document String Similarity Evaluation Data. The SSE data have been finalized after public comment. The SSE data files can be collectively downloaded with this package.
The SSE tool uses the SSE data to determine if any of the input strings are similar to other strings in the scope of comparison. Such cases are identified by the SSE tool as potential contention sets.
The detailed workflow of the SSE tool is included in the SSE guidelines, Appendix A: Workflow of the SSE Tool.
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The SSE is required as a part of the New gTLD Program: 2026 Round application evaluation as per the details found in the New gTLD Program: 2026 Round Applicant Guidebook (AGB), Section 7.10. This is based on the Generic Names Supporting Organization (GNSO) Final Report on the New gTLD Subsequent Procedures Policy Development Process (Section 24) and the Phase 1 Final Report on the Internationalized Domain Names Expedited Policy Development Process.
The SSE is conducted by analyzing comparisons between strings along with their variant strings. This is accomplished through a manual review process based on the pre-screening report generated by the SSE tool using the SSE data, and following the SSE guidelines.
SSE Guidelines
SSE guidelines: String Similarity Evaluation Guidelines for the New gTLD Program: 2026 Round version 1.0
The SSE guidelines will provide direction for the SSE panel on how to manually conduct the string similarity evaluation and how to use the pre-screening report generated by the SSE tool during this analysis. The SSE guidelines have been finalized after public comment.
SSE Data
The SSE data identifies the pairs of code points which are similar, as determined by script experts, and defines the level of similarity between them. The SSE data covers the analysis of the full repertoire of the Root Zone Label Generation Rules (RZ-LGR). The SSE data is tabulated in a machine-readable XML version, intended to be used by the SSE tool, and in a human-readable HTML version.
For details, see the overview document String Similarity Evaluation Data. The SSE data have been finalized after public comment. The SSE data files can be collectively downloaded with this package.
| Script | Similarity Data | |
|---|---|---|
| Common | HTML | XML |
| Arabic | HTML | XML |
| Armenian | HTML | XML |
| Bangla (Bengali) | HTML | XML |
| Chinese | HTML | XML |
| Cyrillic | HTML | XML |
| Devanagari | HTML | XML |
| Ethiopic | HTML | XML |
| Georgian | HTML | XML |
| Greek | HTML | XML |
| Gujarati | HTML | XML |
| Gurmukhi | HTML | XML |
| Hebrew | HTML | XML |
| Japanese (Han + Hiragana + Katakana) | HTML | XML |
| Kannada | HTML | XML |
| Khmer | HTML | XML |
| Korean (Han + Hangul) | HTML | XML |
| Lao | HTML | XML |
| Latin | HTML | XML |
| Malayalam | HTML | XML |
| Myanmar | HTML | XML |
| Oriya | HTML | XML |
| Sinhala | HTML | XML |
| Tamil | HTML | XML |
| Telugu | HTML | XML |
| Thaana | HTML | XML |
| Thai | HTML | XML |
SSE Tool
The SSE tool uses the SSE data to determine if any of the input strings are similar to other strings in the scope of comparison. Such cases are identified by the SSE tool as potential contention sets.
The detailed workflow of the SSE tool is included in the SSE guidelines, Appendix A: Workflow of the SSE Tool.
Continue reading...
