`pub trait EcdsaHash<C: PCurve>: Sealed { }`

## Expand description

A hash function which is compatible with ECDSA signatures over the curve
`C`

.

An ECDSA signature is constructed by hashing the message and then
signing the resulting digest. However, EC keys over certain curves may
not be compatible with all hashes. In particular, some digests may be
too long (in number of bytes) and thus not correspond to a point on the
curve. `EcdsaHash<C>`

is implemented by all hash functions whose digests
are compatible with ECDSA signatures over the curve `C`

.