Slightly more descriptive errors

[gogost.git] / gost3410 / public.go

diff --git a/gost3410/public.go b/gost3410/public.go
index 08e1414000bf6e3d42710b5485e002d74b6e46c7..de2d858c604d793d559c5b11fcdab47fdcc04761 100644 (file)
--- a/gost3410/public.go
+++ b/gost3410/public.go
@@ -16,7 +16,7 @@
 package gost3410
 
 import (
-       "errors"
+       "fmt"
        "math/big"
 )
 
@@ -30,7 +30,7 @@ type PublicKey struct {
 func NewPublicKey(curve *Curve, mode Mode, raw []byte) (*PublicKey, error) {
        key := make([]byte, 2*int(mode))
        if len(raw) != len(key) {
-               return nil, errors.New("Invalid public key length")
+               return nil, fmt.Errorf("gogost/gost3410: len(key) != %d", len(key))
        }
        for i := 0; i < len(key); i++ {
                key[i] = raw[len(raw)-i-1]
@@ -54,11 +54,14 @@ func (pub *PublicKey) Raw() []byte {
 
 func (pub *PublicKey) VerifyDigest(digest, signature []byte) (bool, error) {
        if len(signature) != 2*int(pub.Mode) {
-               return false, errors.New("Invalid signature length")
+               return false, fmt.Errorf("gogost/gost3410: len(signature) != %d", 2*int(pub.Mode))
        }
        s := bytes2big(signature[:pub.Mode])
        r := bytes2big(signature[pub.Mode:])
-       if r.Cmp(zero) <= 0 || r.Cmp(pub.C.Q) >= 0 || s.Cmp(zero) <= 0 || s.Cmp(pub.C.Q) >= 0 {
+       if r.Cmp(zero) <= 0 ||
+               r.Cmp(pub.C.Q) >= 0 ||
+               s.Cmp(zero) <= 0 ||
+               s.Cmp(pub.C.Q) >= 0 {
                return false, nil
        }
        e := bytes2big(digest)