user/crypt/crypt.go
func RegisterCrypt(c Crypt, f func() Crypter, prefix string) {
	if c >= maxCrypt {
		panic("crypt: RegisterHash of unknown crypt function")
	}
	crypts[c] = f
	cryptPrefixes[c] = prefix
}
func RegisterCrypt(c Crypt, f func() Crypter, prefix string) {
	if c >= maxCrypt {
		panic("crypt: RegisterHash of unknown crypt function")
	}
	crypts[c] = f
	cryptPrefixes[c] = prefix
}
// RegisterCrypt registers a function that returns a new instance of the given
// crypt function. This is intended to be called from the init function in
// packages that implement crypt functions.