Information and network security 40 sha3 secure hash algorithm
- 1. Information and Network Security:40 SHA 3 Secure Hash Algorithm Prof Neeraj Bhargava Vaibhav Khanna Department of Computer Science School of Engineering and Systems Sciences Maharshi Dayanand Saraswati University Ajmer
- 2. SHA-3 • SHA-1 not yet "broken” • but similar to broken MD5 & SHA-0 • so considered insecure • SHA-2 (esp. SHA-512) seems secure • shares same structure and mathematical operations as predecessors so have concern • NIST announced in 2007 a competition for the SHA-3 next gen NIST hash function • goal to have in place by 2012 but not fixed
- 3. SHA-3 • As yet, SHA-1 has not yet been "broken". • That is, no one has demonstrated a technique for producing collisions in less than brute-force time. • However, because SHA-1 is very similar in structure and in the basic mathematical operations used to MD5 and SHA-0, both of which have been broken, SHA-1 is considered insecure and has been phased out for SHA-2.
- 4. SHA-3 • SHA-2, particularly the 512-bit version, would appear to provide unassailable security. • However, SHA-2 shares the same structure and mathematical operations as its predecessors, and this is a cause for concern. • Because it will take years to find a suitable replacement for SHA-2, should it become vulnerable, NIST decided to begin the process of developing a new hash standard.
- 5. SHA-3 • Accordingly, NIST announced in 2007 a competition to produce the next generation NIST hash function, to be called SHA-3. • NIST would like to have a new standard in place by the end of 2012, but emphasizes that this is not a fixed timeline.
- 6. SHA-3 Requirements replace SHA-2 with SHA-3 in any use so use same hash sizes preserve the online nature of SHA-2 so must process small blocks (512 / 1024 bits) evaluation criteria security close to theoretical max for hash sizes cost in time & memory characteristics: such as flexibility & simplicity
- 7. SHA-3 Requirements • The basic requirements that must be satisfied by any candidate for SHA-3 are: • It must be possible to replace SHA-2 with SHA-3 in any application by a simple drop-in substitution. Therefore, SHA-3 must support hash value lengths of 224, 256, 384, and 512 bits. • SHA-3 must preserve the online nature of SHA-2. That is, the algorithm must process comparatively small blocks (512 or 1024 bits) at a time instead of requiring that the entire message be buffered in memory before
- 8. SHA-3 Requirements • Beyond these basic requirements, NIST has defined a set of evaluation criteria. These criteria are designed to reflect the requirements for the main applications supported by SHA-2, and are: • • Security: The strength of SHA-3 should be close to the theoretical maximum for the different required hash sizes, and for both preimage resistance and collision resistance. SHA-3 algorithms must be designed to resist any potentially successful attack on SHA-2 functions
- 9. SHA-3 Requirements • • Cost: be both time and memory efficient over a range of hardware platforms. • • Algorithm and implementation characteristics: such as flexibility (e.g., tunable parameters for security/performance tradeoffs, opportunity for parallelization, and so on), and simplicity (which makes it easier to analyze the security properties of the algorithm)
- 10. Assignment • What is SHA 3 Secure Hash Algorithm • Discuss the requirements of SHA 3