golang 中的 ECDH - 椭圆/曲线解组失败

Question

不幸的是，没有内置的 Brainpool 支持，go所以我试图在keybase.也许我在这里犯了一个新手错误，但通过代码，在第一个障碍处就跌倒了（即elliptic.Unmarshal返回零）？package mainimport ( "fmt" "io/ioutil" "log""encoding/pem""crypto/ecdsa""crypto/rand""github.com/keybase/go-crypto/brainpool""crypto/elliptic""crypto/sha256")func main() {fmt.Println("Hello")content, err := ioutil.ReadFile("/tmp/TEST.pem")    if err != nil {        log.Fatal(err)    }fmt.Printf("File contents: %s", content)    block, _ := pem.Decode(content)    if block == nil || block.Type != "PUBLIC KEY" {        log.Fatal("failed to decode PEM")    }x,y := elliptic.Unmarshal(brainpool.P512r1(),block.Bytes)if x == nil {     log.Fatal("failed to unmarshal")}pubb := ecdsa.PublicKey {brainpool.P512r1(),x,y}priva, _ := ecdsa.GenerateKey(brainpool.P512r1(), rand.Reader)b, _ := pubb.Curve.ScalarMult(pubb.X, pubb.Y, priva.D.Bytes())shared1 := sha256.Sum256(b.Bytes())fmt.Printf("\nShared key %x\n",  shared1)更新以显示测试密钥：-----BEGIN PUBLIC KEY-----MIGbMBQGByqGSM49AgEGCSskAwMCCAEBDQOBggAEM/zOLT7nMN374k902oTRZXnG97DPzvqi8QQJaKXcq1BSrU/sNeUhOi6Y+hBcr7ZE+WZDYNoQkaMNrdhF+3x1XGx7BTBFL3U1w2ENmkIPiDa2o0Q/wpSOLo/RFabdK5Q3/yvq0hoSdXlpKozE7UTre5cUbJcUzjXvs9KDLEq54Fs=-----END PUBLIC KEY-----

Answer 1

您正在尝试解组原始 ASN.1 消息，而不是公钥部分。您应该首先解组 ASN.1 块，然后解组 EC 数据。

我的评论是错误的，Go 不支持 Brainpool 功能。因此，我从他们的 X509 包中借用了一些代码，为 Brainpool 包中的 6 条曲线构建了一个自定义解析器。

游乐场：https://play.golang.org/p/i-Zd4mTugjU

package main

import (

    "crypto/ecdsa"

    "crypto/elliptic"

    "crypto/rand"

    "crypto/sha256"

    "crypto/x509/pkix"

    "encoding/asn1"

    "encoding/pem"

    "errors"

    "fmt"

    "log"

    "math/big"

    "github.com/keybase/go-crypto/brainpool"

)

const ecKey = `-----BEGIN PUBLIC KEY-----

MIGbMBQGByqGSM49AgEGCSskAwMCCAEBDQOBggAEM/zOLT7nMN374k902oTRZXnG

97DPzvqi8QQJaKXcq1BSrU/sNeUhOi6Y+hBcr7ZE+WZDYNoQkaMNrdhF+3x1XGx7

BTBFL3U1w2ENmkIPiDa2o0Q/wpSOLo/RFabdK5Q3/yvq0hoSdXlpKozE7UTre5cU

bJcUzjXvs9KDLEq54Fs=

-----END PUBLIC KEY-----`

func main() {

    block, _ := pem.Decode([]byte(ecKey))

    if block == nil || block.Type != "PUBLIC KEY" {

        log.Fatal("failed to decode PEM")

    }

    pub, err := parseBrainpoolPKIXPublicKey(block.Bytes)

    if err != nil {

        log.Fatalf("failed to parse key: %v", err)

    }

    pubb := ecdsa.PublicKey{Curve: brainpool.P512r1(), X: pub.X, Y: pub.Y}

    priva, _ := ecdsa.GenerateKey(brainpool.P512r1(), rand.Reader)

    b, _ := pubb.Curve.ScalarMult(pubb.X, pubb.Y, priva.D.Bytes())

    shared1 := sha256.Sum256(b.Bytes())

    fmt.Printf("\nShared key %x\n", shared1)

}

type publicKeyInfo struct {

    Raw       asn1.RawContent

    Algorithm pkix.AlgorithmIdentifier

    PublicKey asn1.BitString

}

type pkcs1PublicKey struct {

    N *big.Int

    E int

}

var (

    oidNamedCurveBrainpoolP256r1 = asn1.ObjectIdentifier{1, 3, 36, 3, 3, 2, 8, 1, 1, 7}

    oidNamedCurveBrainpoolP256t1 = asn1.ObjectIdentifier{1, 3, 36, 3, 3, 2, 8, 1, 1, 8}

    oidNamedCurveBrainpoolP384r1 = asn1.ObjectIdentifier{1, 3, 36, 3, 3, 2, 8, 1, 1, 11}

    oidNamedCurveBrainpoolP384t1 = asn1.ObjectIdentifier{1, 3, 36, 3, 3, 2, 8, 1, 1, 12}

    oidNamedCurveBrainpoolP512r1 = asn1.ObjectIdentifier{1, 3, 36, 3, 3, 2, 8, 1, 1, 13}

    oidNamedCurveBrainpoolP512t1 = asn1.ObjectIdentifier{1, 3, 36, 3, 3, 2, 8, 1, 1, 14}

)

func parseBrainpoolPKIXPublicKey(derBytes []byte) (pub *ecdsa.PublicKey, err error) {

    var pki publicKeyInfo

    if rest, err := asn1.Unmarshal(derBytes, &pki); err != nil {

        if _, err := asn1.Unmarshal(derBytes, &pkcs1PublicKey{}); err == nil {

            return nil, errors.New("failed to parse public key")

        }

        return nil, err

    } else if len(rest) != 0 {

        return nil, errors.New("trailing data after ASN.1 of public-key")

    }

    if !pki.Algorithm.Algorithm.Equal(asn1.ObjectIdentifier{1, 2, 840, 10045, 2, 1}) {

        return nil, errors.New("not an ECDSA public key")

    }

    return parseBrainpoolPublicKey(&pki)

}

func parseBrainpoolPublicKey(keyData *publicKeyInfo) (*ecdsa.PublicKey, error) {

    asn1Data := keyData.PublicKey.RightAlign()

    paramsData := keyData.Algorithm.Parameters.FullBytes

    namedCurveOID := new(asn1.ObjectIdentifier)

    rest, err := asn1.Unmarshal(paramsData, namedCurveOID)

    if err != nil {

        return nil, errors.New("failed to parse ECDSA parameters as named curve")

    }

    if len(rest) != 0 {

        return nil, errors.New("trailing data after ECDSA parameters")

    }

    namedCurve := namedCurveFromOID(*namedCurveOID)

    if namedCurve == nil {

        return nil, errors.New("unsupported elliptic curve")

    }

    x, y := elliptic.Unmarshal(namedCurve, asn1Data)

    if x == nil {

        return nil, errors.New("failed to unmarshal elliptic curve point")

    }

    pub := &ecdsa.PublicKey{

        Curve: namedCurve,

        X:     x,

        Y:     y,

    }

    return pub, nil

}

func namedCurveFromOID(oid asn1.ObjectIdentifier) elliptic.Curve {

    switch {

    case oid.Equal(oidNamedCurveBrainpoolP256r1):

        return brainpool.P256r1()

    case oid.Equal(oidNamedCurveBrainpoolP256t1):

        return brainpool.P256t1()

    case oid.Equal(oidNamedCurveBrainpoolP384r1):

        return brainpool.P384r1()

    case oid.Equal(oidNamedCurveBrainpoolP384t1):

        return brainpool.P384t1()

    case oid.Equal(oidNamedCurveBrainpoolP512r1):

        return brainpool.P512r1()

    case oid.Equal(oidNamedCurveBrainpoolP512t1):

        return brainpool.P512t1()

    }

    return nil

}