# Tag Info

Accepted

### State of research on SHA-1 Collision Attacks

SHA-1 was SHattered by Stevens et al. They demonstrated that collisions in SHA-1 are practical. They give the first instance of a collision for SHA-1. It is an identical-prefix collision attack that ...
• 206
Accepted

### Factoring assuming smoothness of some numbers

See my paper with Eric Bach, "Factoring with cyclotomic polynomials", where we show that if the cyclotomic polynomial $\Phi_k(p)$ is $B$-smooth for any $p$ dividing $N$, then we can factor $N$ in time ...
• 6,898
Accepted

### Is a "complete" cipher possible?

Yes, you can use Levin universal search to construct a "universal one-way function" (e.g., these lecture notes). From this one-way function you can then construct symmetric-key encryption primitives (...
• 2,789