The `a` parameter should be used in the `MulScalar` function. The upstream cloudflare and google repos have already merged fixes. Reference: * 8d7daa0c54 * https://github.com/cloudflare/bn256/pull/33
8d7daa0c54
* core/vm, crypto/bn256: switch over to cloudflare library * crypto/bn256: unmarshal constraint + start pure go impl * crypto/bn256: combo cloudflare and google lib * travis: drop 386 test job