SMT solving

Bit-blasting

Translating fixed-width operations into Boolean constraints on individual bits.

Definition

Bit-blasting

Bit-blasting lowers a bit-vector formula into a Boolean circuit or CNF formula.

The resulting SAT problem represents each output bit of operations such as addition and multiplication. Correctness depends on the translation preserving the original bit-vector semantics.

01

Example

A two-bit adder becomes Boolean constraints for two sum bits and a carry bit.

02

Important distinction

A SAT certificate checks the lowered Boolean problem, so the bit-blasting translation remains a separate trust boundary unless it is also checked.

After reading this article, you should be able to

  • Define Bit-blasting in the sense used on this site.
  • Describe the information preserved when a bit-vector term is lowered to SAT.