evalphobia/hierogolyph

package scrypt

import (
    "encoding/hex"

    "golang.org/x/crypto/scrypt"
)

const (
    // see: https://godoc.org/golang.org/x/crypto/scrypt
    defaultCost        = 32768
    defaultBlockSize   = 8
    defaultParallelism = 1
    defaultKeyLength   = 32
)

// SCrypt is struct to create hash.
type SCrypt struct {
    Cost        int // N
    BlockSize   int // r
    Parallelism int // p
    KeyLength   int
}

// Hash creates hased text from password.
func (s SCrypt) Hash(password, salt string) string {
    hash, err := scrypt.Key(
        []byte(password),
        []byte(salt),
        s.getCost(),
        s.getBlockSize(),
        s.getParallelism(),
        s.getKeyLength(),
    )
    if err != nil {
        return ""
    }
    return hex.EncodeToString(hash)
}

func (s SCrypt) getCost() int {
    if s.Cost == 0 {
        return defaultCost
    }
    return s.Cost
}

func (s SCrypt) getBlockSize() int {
    if s.BlockSize == 0 {
        return defaultBlockSize
    }
    return s.BlockSize
}

func (s SCrypt) getParallelism() int {
    if s.Parallelism == 0 {
        return defaultParallelism
    }
    return s.Parallelism
}

func (s SCrypt) getKeyLength() int {
    if s.KeyLength == 0 {
        return defaultKeyLength
    }
    return s.KeyLength
}