bcrypt and null kdf done, work on ciphers next (then keytypes)

kdf/errs/errs.go

@@ -0,0 +1,14 @@
+package errs
+
+import (
+	"errors"
+)
+
+var (
+	ErrBadData    = errors.New("unable to cast data into buffer for KDF")
+	ErrNoKeyLen   = errors.New("no key length configured or bad key length for KDF")
+	ErrNoRounds   = errors.New("no rounds number configured or bad number of rounds for KDF")
+	ErrNoSalt     = errors.New("no salt configured or bad salt value for KDF")
+	ErrNoSecret   = errors.New("no secret configured or bad secret value for KDF")
+	ErrUnknownKdf = errors.New("unable to determine matching KDF")
+)