Fix creation date conversion issue

Thanks to @yougg for report
Close #4

common.go

@@ -1,6 +1,9 @@
 package keystore
 
-import "encoding/binary"
+import (
+	"encoding/binary"
+	"time"
+)
 
 const magic uint32 = 0xfeedfeed
 const (
@@ -30,3 +33,11 @@ func zeroing(s []byte) {
 		s[i] = 0
 	}
 }
+
+func millisecondsToTime(ms int64) time.Time {
+	return time.Unix(0, ms*int64(time.Millisecond))
+}
+
+func timeToMilliseconds(t time.Time) int64 {
+	return t.UnixNano() / int64(time.Millisecond)
+}

decoder.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"hash"
 	"io"
-	"time"
 )
 
 const defaultCertificateType = "X509"
@@ -164,7 +163,7 @@ func (ksd *keyStoreDecoder) readPrivateKeyEntry(version uint32, password []byte)
 	if err != nil {
 		return nil, err
 	}
-	creationDateTime := time.Unix(int64(creationDateTimeStamp), 0)
+	creationDateTime := millisecondsToTime(int64(creationDateTimeStamp))
 	privateKeyEntry := PrivateKeyEntry{
 		Entry: Entry{
 			CreationDate: creationDateTime,
@@ -184,7 +183,7 @@ func (ksd *keyStoreDecoder) readTrustedCertificateEntry(version uint32) (*Truste
 	if err != nil {
 		return nil, err
 	}
-	creationDateTime := time.Unix(int64(creationDateTimeStamp), 0)
+	creationDateTime := millisecondsToTime(int64(creationDateTimeStamp))
 	trustedCertificateEntry := TrustedCertificateEntry{
 		Entry: Entry{
 			CreationDate: creationDateTime,

encoder.go

@@ -119,7 +119,7 @@ func (kse *keyStoreEncoder) writeTrustedCertificateEntry(alias string, tce *Trus
 	if err != nil {
 		return err
 	}
-	err = kse.writeUint64(uint64(tce.CreationDate.Unix()))
+	err = kse.writeUint64(uint64(timeToMilliseconds(tce.CreationDate)))
 	if err != nil {
 		return err
 	}
@@ -139,7 +139,7 @@ func (kse *keyStoreEncoder) writePrivateKeyEntry(alias string, pke *PrivateKeyEn
 	if err != nil {
 		return err
 	}
-	err = kse.writeUint64(uint64(pke.CreationDate.Unix()))
+	err = kse.writeUint64(uint64(timeToMilliseconds(pke.CreationDate)))
 	if err != nil {
 		return err
 	}