extra25519

Documentation

Index

• func IsEdLowOrder(ge []byte) bool
• func PrivateKeyToCurve25519(curve25519Private *[32]byte, privateKey ed25519.PrivateKey)
• func PublicKeyToCurve25519(curveBytes *[32]byte, edBytes ed25519.PublicKey) bool

Examples

• PrivateKeyToCurve25519
• PublicKeyToCurve25519

Functions

func IsEdLowOrder

func IsEdLowOrder(ge []byte) bool

IsLowOrder checks if the passed group element is of low order. Algorithm translated from the same source as the blacklist (see above).

func PrivateKeyToCurve25519

func PrivateKeyToCurve25519(curve25519Private *[32]byte, privateKey ed25519.PrivateKey)

PrivateKeyToCurve25519 converts an Ed25519 private key into a corresponding curve25519 private key such that the resulting curve25519 public key will equal the result from PublicKeyToCurve25519.

Example

package main

import (
	"bytes"
	"crypto/ed25519"
	"encoding/hex"
	"fmt"
	"os"

	"github.com/elastic/harp/pkg/sdk/security/crypto/extra25519"
)

func main() {
	dumper := hex.Dumper(os.Stdout)

	// really silly seed for reproduciability
	seed := make([]byte, 32)

	fmt.Println("seed:")
	dumper.Write(seed)

	_, private, err := ed25519.GenerateKey(bytes.NewReader(seed))
	fatal(err)

	fmt.Println("private ed25519:")
	dumper.Write(private)

	var curvPriv [32]byte
	extra25519.PrivateKeyToCurve25519(&curvPriv, private)

	fmt.Println("private curve25519:")
	dumper.Write(curvPriv[:])

}

func fatal(err error) {
	if err != nil {
		panic(err)
	}
}

Output:

seed:
00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000010  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
private ed25519:
00000020  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000030  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000040  3b 6a 27 bc ce b6 a4 2d  62 a3 a8 d0 2a 6f 0d 73  |;j'....-b...*o.s|
00000050  65 32 15 77 1d e2 43 a6  3a c0 48 a1 8b 59 da 29  |e2.w..C.:.H..Y.)|
private curve25519:
00000060  50 46 ad c1 db a8 38 86  7b 2b bb fd d0 c3 42 3e  |PF....8.{+....B>|
00000070  58 b5 79 70 b5 26 7a 90  f5 79 60 92 4a 87 f1 56  |X.yp.&z..y`.J..V|

func PublicKeyToCurve25519

func PublicKeyToCurve25519(curveBytes *[32]byte, edBytes ed25519.PublicKey) bool

PublicKeyToCurve25519 converts an Ed25519 public key into the curve25519 public key that would be generated from the same private key.

Example

package main

import (
	"bytes"
	"crypto/ed25519"
	"encoding/hex"
	"fmt"
	"os"

	"github.com/elastic/harp/pkg/sdk/security/crypto/extra25519"
)

func main() {
	dumper := hex.Dumper(os.Stdout)

	// really silly seed for reproduciability
	seed := make([]byte, 32)

	fmt.Println("seed:")
	dumper.Write(seed)

	public, _, err := ed25519.GenerateKey(bytes.NewReader(seed))
	fatal(err)

	fmt.Println("public ed25519:")
	dumper.Write(public)

	var curvPub [32]byte
	extra25519.PublicKeyToCurve25519(&curvPub, public)

	fmt.Println("public curve25519:")
	dumper.Write(curvPub[:])

}

func fatal(err error) {
	if err != nil {
		panic(err)
	}
}

Output:

seed:
00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000010  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
public ed25519:
00000020  3b 6a 27 bc ce b6 a4 2d  62 a3 a8 d0 2a 6f 0d 73  |;j'....-b...*o.s|
00000030  65 32 15 77 1d e2 43 a6  3a c0 48 a1 8b 59 da 29  |e2.w..C.:.H..Y.)|
public curve25519:
00000040  5b f5 5c 73 b8 2e be 22  be 80 f3 43 06 67 af 57  |[.\s..."...C.g.W|
00000050  0f ae 25 56 a6 41 5e 6b  30 d4 06 53 00 aa 94 7d  |..%V.A^k0..S...}|