Files
phylum/server/internal/cryptutil/argon2.go
2024-05-10 03:39:24 +05:30

117 lines
2.8 KiB
Go

package cryptutil
import (
"crypto/rand"
"crypto/subtle"
"encoding/base64"
"errors"
"fmt"
"strings"
"golang.org/x/crypto/argon2"
)
type Argon2Params struct {
salt uint32
key uint32
memory uint32
iterations uint32
parallelism uint8
}
func DefaultArgon2Params() Argon2Params {
return Argon2Params{
salt: 32,
key: 32,
memory: 2048,
iterations: 6,
parallelism: 4,
}
}
func GenerateArgon2EncodedHash(password string, p Argon2Params) (string, error) {
salt, err := generateRandomBytes(p.salt)
if err != nil {
return "", err
}
key := argon2.IDKey([]byte(password), salt, p.iterations, p.memory, p.parallelism, p.key)
b64Salt := base64.RawStdEncoding.EncodeToString(salt)
b64Hash := base64.RawStdEncoding.EncodeToString(key)
// Return a string using the standard encoded hash representation.
return fmt.Sprintf("$argon2id$v=%d$m=%d,t=%d,p=%d$%s$%s", argon2.Version, p.memory, p.iterations, p.parallelism, b64Salt, b64Hash), nil
}
func VerifyPassword(password, encodedHash string) (bool, error) {
// Extract the parameters, salt and derived key from the encoded password
// hash.
p, salt, hash, err := decodeHash(encodedHash)
if err != nil {
return false, err
}
// Derive the key from the other password using the same parameters.
otherHash := argon2.IDKey([]byte(password), salt, p.iterations, p.memory, p.parallelism, p.key)
// Check that the contents of the hashed passwords are identical. Note
// that we are using the subtle.ConstantTimeCompare() function for this
// to help prevent timing attacks.
if subtle.ConstantTimeCompare(hash, otherHash) == 1 {
return true, nil
}
return false, nil
}
func decodeHash(encodedHash string) (p *Argon2Params, salt, hash []byte, err error) {
vals := strings.Split(encodedHash, "$")
if vals[1] != "argon2id" {
return nil, nil, nil, errors.New("unrecognized hash")
}
if len(vals) != 6 {
return nil, nil, nil, errors.New("incorrect hash format for argon2id")
}
var version int
_, err = fmt.Sscanf(vals[2], "v=%d", &version)
if err != nil {
return nil, nil, nil, err
}
if version != argon2.Version {
return nil, nil, nil, errors.New("unrecognized version of argon2")
}
p = &Argon2Params{}
_, err = fmt.Sscanf(vals[3], "m=%d,t=%d,p=%d", &p.memory, &p.iterations, &p.parallelism)
if err != nil {
return nil, nil, nil, err
}
salt, err = base64.RawStdEncoding.Strict().DecodeString(vals[4])
if err != nil {
return nil, nil, nil, err
}
p.salt = uint32(len(salt))
hash, err = base64.RawStdEncoding.Strict().DecodeString(vals[5])
if err != nil {
return nil, nil, nil, err
}
p.key = uint32(len(hash))
return p, salt, hash, nil
}
// Generate a cryptographically secure random salt.
func generateRandomBytes(n uint32) ([]byte, error) {
b := make([]byte, n)
_, err := rand.Read(b)
if err != nil {
return nil, err
}
return b, nil
}