Use PBKDF2-HMAC-SHA512 for key derivation

1 files changed, 7 insertions, 19 deletions

diff --git a/internal/pwhash/pwhash.go b/internal/pwhash/pwhash.go
index f343d70..3074b0c 100644
--- a/internal/pwhash/pwhash.go
+++ b/internal/pwhash/pwhash.go
@@ -1,36 +1,24 @@
 package pwhash
 
 import (
-	"crypto/hkdf"
 	"crypto/pbkdf2"
-	"crypto/sha256"
 	"crypto/sha512"
-	"fmt"
 )
 
-const SaltLen = sha256.Size + sha512.Size
+const SaltLen = sha512.Size
 
-const defaultIterations = 3670016 // from cmd/finditers
+const defaultIterations = 903636 // from cmd/finditers
 
 func HashIter(password string, salt []byte, iter int) ([]byte, error) {
-	return pbkdf2.Key(sha256.New, password, salt, iter, sha256.Size)
+	return pbkdf2.Key(sha512.New, password, salt, iter, sha512.Size)
 }
 
 func Hash(password string, salt []byte) (key, pwHash []byte, err error) {
-	if len(salt) != SaltLen {
-		return nil, nil, fmt.Errorf("bad salt size")
-	}
-	hashedPassword, err := HashIter(password, salt[:sha256.Size], defaultIterations)
-	if err != nil {
-		return nil, nil, err
-	}
-	key, err = hkdf.Extract(sha512.New, hashedPassword, salt[sha256.Size:])
-	if err != nil {
-		return nil, nil, err
-	}
-	pwHash, err = hkdf.Expand(sha512.New, key, "auth", sha512.Size)
+	const aesKeySize = 32
+
+	key, err = HashIter(password, salt, defaultIterations)
 	if err != nil {
 		return nil, nil, err
 	}
-	return key, pwHash, nil
+	return key[:aesKeySize], key[aesKeySize:], nil
 }