Static ring::digest::SHA256

pub static SHA256: Algorithm = Algorithm{output_len: 256 / 8,
          chaining_len: 256 / 8,
          block_len: 512 / 8,
          len_len: 64 / 8,
          block_data_order: GFp_sha256_block_data_order,
          format_output: sha256_format_output,
          initial_state:
              [3144134277u32 as u64 << 32 | 1779033703u32 as u64,
               2773480762u32 as u64 << 32 | 1013904242u32 as u64,
               2600822924u32 as u64 << 32 | 1359893119u32 as u64,
               1541459225u32 as u64 << 32 | 528734635u32 as u64, 0, 0, 0, 0],}

SHA-256 as specified in FIPS 180-4.