renommage lassistanoque

backend/internal/adapter/auth/password/argon2_hasher.go

@@ -0,0 +1,130 @@
+package password
+
+import (
+	"crypto/rand"
+	"crypto/subtle"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"strings"
+
+	"golang.org/x/crypto/argon2"
+)
+
+type params struct {
+	memory      uint32 // en KiB
+	iterations  uint32
+	parallelism uint8
+	saltLength  uint32
+	keyLength   uint32
+}
+
+var defaultParams = &params{
+	memory:      64 * 1024, // 64 MB
+	iterations:  3,
+	parallelism: 2,
+	saltLength:  16,
+	keyLength:   32,
+}
+
+// generateSalt crée un salt aléatoire cryptographiquement sûr
+func generateSalt(length uint32) ([]byte, error) {
+	salt := make([]byte, length)
+	if _, err := rand.Read(salt); err != nil {
+		return nil, err
+	}
+	return salt, nil
+}
+
+// HashPassword génère un hash Argon2id encodé (salt + hash + paramètres inclus)
+func HashPassword(password string) (string, error) {
+	salt, err := generateSalt(defaultParams.saltLength)
+	if err != nil {
+		return "", err
+	}
+
+	hash := argon2.IDKey(
+		[]byte(password),
+		salt,
+		defaultParams.iterations,
+		defaultParams.memory,
+		defaultParams.parallelism,
+		defaultParams.keyLength,
+	)
+
+	// Format standard: $argon2id$v=19$m=65536,t=3,p=2$salt$hash
+	b64Salt := base64.RawStdEncoding.EncodeToString(salt)
+	b64Hash := base64.RawStdEncoding.EncodeToString(hash)
+
+	encoded := fmt.Sprintf(
+		"$argon2id$v=%d$m=%d,t=%d,p=%d$%s$%s",
+		argon2.Version,
+		defaultParams.memory,
+		defaultParams.iterations,
+		defaultParams.parallelism,
+		b64Salt,
+		b64Hash,
+	)
+
+	return encoded, nil
+}
+
+// VerifyPassword compare un mot de passe en clair avec un hash stocké
+func VerifyPassword(password, encodedHash string) (bool, error) {
+	p, salt, hash, err := decodeHash(encodedHash)
+	if err != nil {
+		return false, err
+	}
+
+	otherHash := argon2.IDKey(
+		[]byte(password),
+		salt,
+		p.iterations,
+		p.memory,
+		p.parallelism,
+		p.keyLength,
+	)
+
+	// Comparaison en temps constant pour éviter les timing attacks
+	if subtle.ConstantTimeCompare(hash, otherHash) == 1 {
+		return true, nil
+	}
+	return false, nil
+}
+
+// decodeHash parse la chaîne encodée pour en extraire params, salt et hash
+func decodeHash(encodedHash string) (*params, []byte, []byte, error) {
+	parts := strings.Split(encodedHash, "$")
+	if len(parts) != 6 {
+		return nil, nil, nil, errors.New("format de hash invalide")
+	}
+
+	var version int
+	_, err := fmt.Sscanf(parts[2], "v=%d", &version)
+	if err != nil {
+		return nil, nil, nil, err
+	}
+	if version != argon2.Version {
+		return nil, nil, nil, errors.New("version argon2 incompatible")
+	}
+
+	p := &params{}
+	_, err = fmt.Sscanf(parts[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.DecodeString(parts[4])
+	if err != nil {
+		return nil, nil, nil, err
+	}
+	p.saltLength = uint32(len(salt))
+
+	hash, err := base64.RawStdEncoding.DecodeString(parts[5])
+	if err != nil {
+		return nil, nil, nil, err
+	}
+	p.keyLength = uint32(len(hash))
+
+	return p, salt, hash, nil
+}