From 08fac28e738cef66933374c6be2246b77c009be6 Mon Sep 17 00:00:00 2001
From: Alexander Neumann <alexander@bumpern.de>
Date: Sun, 3 May 2015 17:51:04 +0200
Subject: [PATCH] crypto: Remove polynomial from key

---
 crypto/crypto.go | 13 +++----------
 server/key.go    | 17 -----------------
 2 files changed, 3 insertions(+), 27 deletions(-)

diff --git a/crypto/crypto.go b/crypto/crypto.go
index 418d80f8a..3e7aedf07 100644
--- a/crypto/crypto.go
+++ b/crypto/crypto.go
@@ -8,7 +8,6 @@ import (
 	"errors"
 	"fmt"
 
-	"github.com/restic/restic/chunker"
 	"golang.org/x/crypto/poly1305"
 	"golang.org/x/crypto/scrypt"
 )
@@ -35,12 +34,10 @@ var (
 
 // Key holds encryption and message authentication keys for a repository. It is stored
 // encrypted and authenticated as a JSON data structure in the Data field of the Key
-// structure. For the master key, the secret random polynomial used for content
-// defined chunking is included.
+// structure.
 type Key struct {
-	MAC               MACKey        `json:"mac"`
-	Encrypt           EncryptionKey `json:"encrypt"`
-	ChunkerPolynomial chunker.Pol   `json:"chunker_polynomial,omitempty"`
+	MAC     MACKey        `json:"mac"`
+	Encrypt EncryptionKey `json:"encrypt"`
 }
 
 type EncryptionKey [32]byte
@@ -340,9 +337,5 @@ func KDF(N, R, P int, salt []byte, password string) (*Key, error) {
 
 // Valid tests if the key is valid.
 func (k *Key) Valid() bool {
-	if k.ChunkerPolynomial != 0 && !k.ChunkerPolynomial.Irreducible() {
-		return false
-	}
-
 	return k.Encrypt.Valid() && k.MAC.Valid()
 }
diff --git a/server/key.go b/server/key.go
index 1e4294984..097ff6051 100644
--- a/server/key.go
+++ b/server/key.go
@@ -12,9 +12,7 @@ import (
 	"time"
 
 	"github.com/restic/restic/backend"
-	"github.com/restic/restic/chunker"
 	"github.com/restic/restic/crypto"
-	"github.com/restic/restic/debug"
 )
 
 var (
@@ -92,13 +90,6 @@ func OpenKey(s *Server, name string, password string) (*Key, error) {
 		return nil, errors.New("Invalid key for repository")
 	}
 
-	// test if the chunker polynomial is present in the master key
-	if k.master.ChunkerPolynomial == 0 {
-		return nil, errors.New("Polynomial for content defined chunking is zero")
-	}
-
-	debug.Log("OpenKey", "Master keys loaded, polynomial %v", k.master.ChunkerPolynomial)
-
 	return k, nil
 }
 
@@ -177,14 +168,6 @@ func AddKey(s *Server, password string, template *Key) (*Key, error) {
 	if template == nil {
 		// generate new random master keys
 		newkey.master = crypto.NewRandomKey()
-		// generate random polynomial for cdc
-		p, err := chunker.RandomPolynomial()
-		if err != nil {
-			debug.Log("AddKey", "error generating new polynomial for cdc: %v", err)
-			return nil, err
-		}
-		debug.Log("AddKey", "generated new polynomial for cdc: %v", p)
-		newkey.master.ChunkerPolynomial = p
 	} else {
 		// copy master keys from old key
 		newkey.master = template.master