Use AES-CTR-HMAC-SHA256 instead of AES-GCM

1 files changed, 17 insertions, 8 deletions

diff --git a/internal/pwhash/pwhash.go b/internal/pwhash/pwhash.go
index d886746..9ef5d2a 100644
--- a/internal/pwhash/pwhash.go
+++ b/internal/pwhash/pwhash.go
@@ -1,24 +1,33 @@
 package pwhash
 
 import (
+	"crypto/hkdf"
 	"crypto/pbkdf2"
-	"crypto/sha512"
+	"crypto/sha256"
 )
 
-const SaltLen = sha512.Size
+const SaltLen = 2 * sha256.Size
 
-const defaultIterations = 1220340 // from cmd/finditers
+const defaultIterations = 3749890 // from cmd/finditers
 
 func HashIter(password string, salt []byte, iter int) ([]byte, error) {
-	return pbkdf2.Key(sha512.New, password, salt, iter, sha512.Size)
+	return pbkdf2.Key(sha256.New, password, salt, iter, sha256.Size)
 }
 
-func Hash(password string, salt []byte) (key, pwHash []byte, err error) {
-	const aesKeySize = 32
+func Hash(password string, salt []byte) (rawKey, pwHash []byte, err error) {
+	const hashLen = 32
 
-	key, err = HashIter(password, salt, defaultIterations)
+	key, err := HashIter(password, salt[:sha256.Size], defaultIterations)
 	if err != nil {
 		return nil, nil, err
 	}
-	return key[:aesKeySize], key[aesKeySize:], nil
+	key, err = hkdf.Extract(sha256.New, key, salt[sha256.Size:])
+	if err != nil {
+		return nil, nil, err
+	}
+	pwHash, err = hkdf.Expand(sha256.New, key, "pwhash", hashLen)
+	if err != nil {
+		return nil, nil, err
+	}
+	return key, pwHash, nil
 }