sha256零知识证明constraints对比

在 https://github.com/ebfull/lightning_circuit （2016年，使用deprecated-master版本的libsnark）中，记录的performance为：

on computer (Intel® Core™ i7-3770S CPU @ 3.10GHz):

• key generation time: 11.6551s
• proof generation time: 3.0884s
• verification time: 0.0262s
• proof size: 2294 bits
• proving key size: 102284136 bits
• verifying key size: 4586 bits
• R1CS constraints: 56101 (mostly sha256-related)

在 https://github.com/3for/xjsnark （2019年），有提到：

Example (previews)	Description	Number of constraints
SHA-256 (Unpadded)	High-level implementation of SHA-256 which is compiled to an optimized circuit similar to the one produced by manual/low-level libraries, as in jsnark.	25538