可做为公钥，可做为见证，可进行数学/密码学上的求和。

由两部分组成，表示了钱、拥有权。

/// The size of a Pedersen commitment
pub const PEDERSEN_COMMITMENT_SIZE: usize = 33;

/// A Pedersen commitment
pub struct Commitment(pub [u8; constants::PEDERSEN_COMMITMENT_SIZE]);

Committed

Commitment 的求和。

/// Implemented by types that hold inputs and outputs (and kernels)
/// containing Pedersen commitments.
/// Handles the collection of the commitments as well as their
/// summing, taking potential explicit overages of fees into account.

verify_kernel_sums

    /// Verify the sum of the kernel excesses equals the
    /// sum of the outputs, taking into account both
    /// the kernel_offset and overage.

sum_commitments

/// Gathers commitments and sum them.

/// Utility to sum positive and negative commitments, eliminating zero values

sum_kernel_excesses

/// Gather the kernel excesses and sum them.

/// Utility function to take sets of positive and negative kernel offsets as
/// blinding factors, convert them to private key filtering zero values and
/// summing all of them. Useful to build blocks.