### Abstract

Given an n-bit to n-bit MAC (e.g., a fixed key blockcipher) with MAC security ε against q queries, we design a variable-length MAC achieving MAC security O(εq,poly(n)) against queries of total length qn. In particular, our construction is the first to break the "birthday barrier" for MAC domain extension from noncompressing primitives, since our security bound is meaningful even for q = 2^{n}/poly(n) (assuming ε is the best possible O(1/2^{n})). In contrast, the previous best construction for MAC domain extension for n-bit to n-bit primitives, due to Dodis and Steinberger [11], achieved MAC security of O(εq^{2}(log q)^{2}), which means that q cannot cross the "birthday bound" of 2^{n/2}.

Original language | English (US) |
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Title of host publication | Advances in Cryptology - EUROCRYPT 2011, 30th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Proceedings |

Pages | 323-342 |

Number of pages | 20 |

DOIs | |

State | Published - 2011 |

Event | 30th Annual International Conference on the Theory and Applications of Cryptographic Techniques Advances in Cryptology, EUROCRYPT 2011 - Tallinn, Estonia Duration: May 15 2011 → May 19 2011 |

### Publication series

Name | Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) |
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Volume | 6632 LNCS |

ISSN (Print) | 0302-9743 |

ISSN (Electronic) | 1611-3349 |

### Other

Other | 30th Annual International Conference on the Theory and Applications of Cryptographic Techniques Advances in Cryptology, EUROCRYPT 2011 |
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Country | Estonia |

City | Tallinn |

Period | 5/15/11 → 5/19/11 |

### ASJC Scopus subject areas

- Theoretical Computer Science
- Computer Science(all)

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## Cite this

*Advances in Cryptology - EUROCRYPT 2011, 30th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Proceedings*(pp. 323-342). (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); Vol. 6632 LNCS). https://doi.org/10.1007/978-3-642-20465-4_19