[lib.context] added 'minDepth' and 'depthThreshold' + [client.keyset] added context management

src/git.xdrm.io/schastsp/client/keyset/keyset.go

@@ -1,6 +1,7 @@
 package keyset
 
 import (
+	"git.xdrm.io/schastsp/lib/context"
 	"io"
 	"encoding/binary"
 	"errors"
@@ -13,12 +14,12 @@ const a = 12
 
 /* Attributes */
 type Set struct {
-	min   uint16 // min depth
-	depth uint16 // cur depth
-	max   uint16 // max depth
+	ctx   *context.Context // current context
+	depth uint16           // cur depth
+	max   uint16           // max depth
 
-	sec         []byte // secret
-	consumption uint   // consumption level
+	sec         []byte     // secret
+	consumption uint       // consumption level
 	// 0: none
 	// 1: need to migrate
 	// 2: waiting migration
@@ -33,18 +34,18 @@ type Set struct {
 * @return outName<outType>			outDesc
 *
 ---------------------------------------------------------*/
-func Create(min uint16, max uint16) (*Set, error) {
+func Create(ctx *context.Context, max uint16) (*Set, error) {
 
-	/* (1) Fail if min >= max */
-	if min >= max {
-		return nil, errors.New("Max depth is not greater than Min depth")
+	/* (1) Fail if min+thre >= max */
+	if ctx.MinDepth()+ctx.DepthThreshold() >= max {
+		return nil, errors.New("Maximum depth must be greater than Min+threshold (from given Context)")
 	}
 
 	/* (2) Instanciate */
 	var instance = new(Set)
 
 	/* (3) Set attributes */
-	instance.min = min
+	instance.ctx = ctx
 	instance.max = max
 
 	/* (4) Generate values if <nil> secret */
@@ -76,7 +77,7 @@ func (s *Set) generate() {
 	/* (2) Manage other attributes
 	---------------------------------------------------------*/
 	/* (1) Random depth pick init */
-	var randMin, randMax uint16 = s.min + (s.max-s.min)/2, s.max
+	var randMin, randMax uint16 = s.ctx.MinDepth() + (s.max-s.ctx.MinDepth())/2, s.max
 
 	/* (2) Select "random" depth */
 	s.depth = randMin + uint16(rand.Intn(int(randMax-randMin)))
@@ -117,7 +118,7 @@ func (s *Set) Decrement() uint16 {
 	s.depth--
 
 	/* (2) If near minDepth (10 far): set consumption to 1 */
-	if s.depth <= s.min+10 {
+	if s.depth <= s.ctx.MinDepth()+s.ctx.DepthThreshold() {
 		s.consumption = 1
 	}
 
@@ -146,7 +147,7 @@ func (s *Set) Write(writer io.Writer) error {
 
 	var err error;
 
-	/* (1) Copy hash size */
+	/* (1) Copy secret size */
 	err = binary.Write(writer, binary.BigEndian, scha.HSIZE)
 	if err != nil { return err }
 
@@ -178,16 +179,12 @@ func (s *Set) Write(writer io.Writer) error {
 ---------------------------------------------------------*/
 func (s *Set) Read(reader io.Reader) error {
 
-	var (
-		err error
-		secretLength uint16
-	)
+	var err error
+	var secretLength uint16
 
 	/* (1) Read the secret size */
 	err = binary.Read(reader, binary.BigEndian, &secretLength)
-	if err != nil {
-		return err
-	}
+	if err != nil { return err }
 
 	/* (2) Fail if secretLength different than digest size */
 	if secretLength != scha.HSIZE {

src/git.xdrm.io/schastsp/lib/context/context.go

@@ -1,20 +1,37 @@
 package context
 
+import (
+	"errors"
+)
+
 /* (1) Context class
 ---------------------------------------------------------*/
 /* (1) Attributes */
 type Context struct {
-	windowSize   float64; // 'timeid' window size
+	win        float64; // 'timeid' window size
+	dMin       uint16;  // minimum scha depth
+	dThreshold uint16;  // scha depth threshold
 }
 
 /* (2) Constructor */
-func Create(winSize float64) *Context{
+func Create(win float64, dMin uint16, dThreshold uint16) (*Context, error) {
 	var instance = new(Context);
 
-	instance.windowSize = winSize;
+	/* (1) Window size error */
+	if win < 0 { return nil, errors.New("Window size must be positive and is negative") }
+	instance.win = win;
 
-	return instance
+	/* (2) Minimum Depth error */
+	if dMin < 0x0f { return nil, errors.New("Minimum depth must be greater than 0x0f (decimal 15) for consistency issues") }
+	instance.dMin = dMin;
+
+	/* (3) Depth Threshold error */
+	instance.dThreshold = dThreshold;
+
+	return instance, nil
 }
 
 /* (3) Getters */
-func (c Context) GetWindowSize()   float64 { return c.windowSize }
+func (c Context) Window()         float64 { return c.win }
+func (c Context) MinDepth()       uint16  { return c.dMin }
+func (c Context) DepthThreshold() uint16  { return c.dThreshold }