evalphobia/hierogolyph

package balloon

import (
    "crypto/sha512"
    "encoding/hex"
    "hash"

    "github.com/nogoegst/balloon"
)

const (
    // see: https://godoc.org/github.com/nogoegst/balloon
    defaultSpaceCost   = 16
    defaultTimeCost    = 16
    defaultParallelism = 1
)

var (
    defaultHashFn = sha512.New
)

// Balloon is struct to create hash.
type Balloon struct {
    HashFn      func() hash.Hash
    SpaceCost   uint64
    TimeCost    uint64
    Parallelism uint64 // p
}

// Hash creates hased text from password.
func (b Balloon) Hash(password, salt string) string {
    return hex.EncodeToString(balloon.BalloonM(
        b.getHashFn(),
        []byte(password),
        []byte(salt),
        b.getSpaceCost(),
        b.getTimeCost(),
        b.getParallelism(),
    ))
}

func (b Balloon) getHashFn() func() hash.Hash {
    if b.HashFn == nil {
        return defaultHashFn
    }
    return b.HashFn
}

func (b Balloon) getSpaceCost() uint64 {
    if b.SpaceCost == 0 {
        return defaultSpaceCost
    }
    return b.SpaceCost
}

func (b Balloon) getTimeCost() uint64 {
    if b.TimeCost == 0 {
        return defaultTimeCost
    }
    return b.TimeCost
}

func (b Balloon) getParallelism() uint64 {
    if b.Parallelism == 0 {
        return defaultParallelism
    }
    return b.Parallelism
}