Merge branch 'XX-3076/ContactFP' into 'agile/EphemeralReception'

Add Fingerprint for Contact and tests

See merge request !503

interfaces/contact/contact.go

@@ -9,6 +9,8 @@ package contact
 
 import (
 	"bytes"
+	"crypto"
+	"encoding/base64"
 	"encoding/binary"
 	"github.com/pkg/errors"
 	"gitlab.com/elixxir/crypto/cyclic"
@@ -17,6 +19,7 @@ import (
 )
 
 const sizeByteLength = 2
+const fingerprintLength = 15
 
 // Contact implements the Contact interface defined in interface/contact.go,
 // in go, the structure is meant to be edited directly, the functions are for
@@ -77,6 +80,22 @@ func (c Contact) Marshal() []byte {
 	return buff.Bytes()
 }
 
+// Creates a 15 character long fingerprint of contact
+// off of the ID and DH public key
+func (c Contact) GetFingerprint() string {
+	// Generate hash
+	sha := crypto.SHA256
+	h := sha.New()
+
+	// Hash Id and public key
+	h.Write(c.ID.Bytes())
+	h.Write(c.DhPubKey.Bytes())
+	data := h.Sum(nil)
+
+	// Encode hash and truncate
+	return base64.StdEncoding.EncodeToString(data[:])[:fingerprintLength]
+}
+
 // Unmarshal decodes the byte slice produced by Contact.Marshal into a Contact.
 func Unmarshal(b []byte) (Contact, error) {
 	if len(b) < sizeByteLength*3+id.ArrIDLen {

interfaces/contact/contact_test.go

+///////////////////////////////////////////////////////////////////////////////
+// Copyright © 2020 xx network SEZC                                          //
+//                                                                           //
+// Use of this source code is governed by a license that can be found in the //
+// LICENSE file                                                              //
+///////////////////////////////////////////////////////////////////////////////
+
 package contact
 
 import (
+	"crypto"
+	"encoding/base64"
 	"encoding/json"
 	"gitlab.com/elixxir/crypto/cyclic"
 	"gitlab.com/elixxir/primitives/fact"
@@ -9,6 +18,7 @@ import (
 	"gitlab.com/xx_network/primitives/id"
 	"math/rand"
 	"reflect"
+	"strings"
 	"testing"
 )
 
@@ -88,6 +98,82 @@ func TestContact_Marshal_Size(t *testing.T) {
 	}
 }
 
+// Unit test of getFingerprint
+func TestContact_GetFingerprint(t *testing.T) {
+	c := Contact{
+		ID:       id.NewIdFromString("Samwise", id.User, t),
+		DhPubKey: getCycInt(512),
+	}
+
+	contactString := c.GetFingerprint()
+	if len(contactString) != fingerprintLength {
+		t.Errorf("Unexpected length for fingerprint."+
+			"\n\tExpected length: %d"+
+			"\n\tReceived length: %d", len(contactString), fingerprintLength)
+	}
+
+	// Generate hash
+	sha := crypto.SHA256
+	h := sha.New()
+
+	// Hash Id and public key
+	h.Write(c.ID.Bytes())
+	h.Write(c.DhPubKey.Bytes())
+	data := h.Sum(nil)
+
+	expectedFP := base64.StdEncoding.EncodeToString(data[:])[:fingerprintLength]
+
+	if strings.Compare(contactString, expectedFP) != 0 {
+		t.Errorf("Fingerprint outputted is not expected."+
+			"\n\tExpected: %s"+
+			"\n\tReceived: %s", contactString, expectedFP)
+	}
+
+}
+
+// Consistency test for changes in underlying dependencies
+func TestContact_GetFingerprint_Consistency(t *testing.T) {
+	expected := []string{
+		"rBUw1n4jtH4uEYq",
+		"Z/Jm1OUwDaql5cd",
+		"+vHLzY+yH96zAiy",
+		"cZm5Iz78ViOIlnh",
+		"9LqrcbFEIV4C4LX",
+		"ll4eykGpMWYlxw+",
+		"6YQshWJhdPL6ajx",
+		"Y6gTPVEzow4IHOm",
+		"6f/rT2vWxDC9tdt",
+		"rwqbDT+PoeA6Iww",
+		"YN4IFijP/GZ172O",
+		"ScbHVQc2T9SXQ2m",
+		"50mfbCXQ+LIqiZn",
+		"cyRYdMKXByiFdtC",
+		"7g6ujy7iIbJVl4F",
+	}
+
+	numTest := 15
+	output := make([]string, 0)
+	for i := 0; i < numTest; i++ {
+		c := Contact{
+			ID:       id.NewIdFromUInt(uint64(i), id.User, t),
+			DhPubKey: getGroup().NewInt(25),
+		}
+
+		contactString := c.GetFingerprint()
+		output = append(output, contactString)
+	}
+
+	for i := 0; i < numTest; i++ {
+		if strings.Compare(output[i], expected[i]) != 0 {
+			t.Errorf("Fingerprint outputted is not expected."+
+				"\n\tReceived: %s"+
+				"\n\tExpected: %s", output[i], expected[i])
+		}
+
+	}
+
+}
+
 func getCycInt(size int) *cyclic.Int {
 	var primeString = "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" +
 		"29024E088A67CC74020BBEA63B139B22514A08798E3404DD" +
@@ -119,3 +205,21 @@ func getCycInt(size int) *cyclic.Int {
 	grp := cyclic.NewGroup(large.NewIntFromString(primeString, 16), large.NewInt(2)).NewIntFromBytes(buff)
 	return grp
 }
+
+func getGroup() *cyclic.Group {
+	return cyclic.NewGroup(
+		large.NewIntFromString("E2EE983D031DC1DB6F1A7A67DF0E9A8E5561DB8E8D4941"+
+			"3394C049B7A8ACCEDC298708F121951D9CF920EC5D146727AA4AE535B0922C688"+
+			"B55B3DD2AEDF6C01C94764DAB937935AA83BE36E67760713AB44A6337C20E7861"+
+			"575E745D31F8B9E9AD8412118C62A3E2E29DF46B0864D0C951C394A5CBBDC6ADC"+
+			"718DD2A3E041023DBB5AB23EBB4742DE9C1687B5B34FA48C3521632C4A530E8FF"+
+			"B1BC51DADDF453B0B2717C2BC6669ED76B4BDD5C9FF558E88F26E5785302BEDBC"+
+			"A23EAC5ACE92096EE8A60642FB61E8F3D24990B8CB12EE448EEF78E184C7242DD"+
+			"161C7738F32BF29A841698978825B4111B4BC3E1E198455095958333D776D8B2B"+
+			"EEED3A1A1A221A6E37E664A64B83981C46FFDDC1A45E3D5211AAF8BFBC072768C"+
+			"4F50D7D7803D2D4F278DE8014A47323631D7E064DE81C0C6BFA43EF0E6998860F"+
+			"1390B5D3FEACAF1696015CB79C3F9C2D93D961120CD0E5F12CBB687EAB045241F"+
+			"96789C38E89D796138E6319BE62E35D87B1048CA28BE389B575E994DCA7554715"+
+			"84A09EC723742DC35873847AEF49F66E43873", 16),
+		large.NewIntFromString("2", 16))
+}