bcrypt.go

// +build go1.11

package passwd

import "golang.org/x/crypto/bcrypt"

var (
	bcryptCommonParameters   = BcryptParams{Cost: bcrypt.DefaultCost}
	bcryptParanoidParameters = BcryptParams{Cost: bcrypt.MaxCost}
)

const (
	idBcrypt = "2a"
)

// BcryptParams are the parameters for the bcrypt key derivation.
type BcryptParams struct {
	Cost   int
	Masked bool // XXX UNUSED
}

func newBcryptParamsFromHash(hashed []byte) (*BcryptParams, error) {
	hashCost, err := bcrypt.Cost(hashed)
	if err != nil {
		return nil, err
	}

	bp := BcryptParams{
		Cost: hashCost,
	}
	return &bp, nil
}

func (bp *BcryptParams) generateFromPassword(password []byte) ([]byte, error) {
	return bcrypt.GenerateFromPassword(password, bp.Cost)
}

func (bp *BcryptParams) compare(hashed, password []byte) error {
	hashCost, err := bcrypt.Cost(hashed)
	if err != nil || hashCost != bp.Cost {
		return ErrMismatch
	}

	err = bcrypt.CompareHashAndPassword(hashed, password)
	if err != nil {
		return ErrMismatch
	}
	return nil
}