61 lines
1.7 KiB
Go
61 lines
1.7 KiB
Go
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// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the Golang LICENSE file.
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package main
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import (
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"crypto/ecdsa"
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"crypto/elliptic"
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"encoding/asn1"
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"errors"
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)
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// ecPrivateKey reflects an ASN.1 Elliptic Curve Private Key Structure.
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// References:
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// RFC5915
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// SEC1 - http://www.secg.org/download/aid-780/sec1-v2.pdf
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// Per RFC5915 the NamedCurveOID is marked as ASN.1 OPTIONAL, however in
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// most cases it is not.
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type ecPrivateKey struct {
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Version int
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PrivateKey []byte
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NamedCurveOID asn1.ObjectIdentifier `asn1:"optional,explicit,tag:0"`
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PublicKey asn1.BitString `asn1:"optional,explicit,tag:1"`
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}
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var (
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oidNamedCurveP224 = asn1.ObjectIdentifier{1, 3, 132, 0, 33}
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oidNamedCurveP256 = asn1.ObjectIdentifier{1, 2, 840, 10045, 3, 1, 7}
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oidNamedCurveP384 = asn1.ObjectIdentifier{1, 3, 132, 0, 34}
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oidNamedCurveP521 = asn1.ObjectIdentifier{1, 3, 132, 0, 35}
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)
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func oidFromNamedCurve(curve elliptic.Curve) (asn1.ObjectIdentifier, bool) {
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switch curve {
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case elliptic.P224():
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return oidNamedCurveP224, true
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case elliptic.P256():
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return oidNamedCurveP256, true
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case elliptic.P384():
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return oidNamedCurveP384, true
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case elliptic.P521():
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return oidNamedCurveP521, true
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}
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return nil, false
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}
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func MarshalECPrivateKey(key *ecdsa.PrivateKey) ([]byte, error) {
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oid, ok := oidFromNamedCurve(key.Curve)
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if !ok {
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return nil, errors.New("x509: unknown elliptic curve")
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}
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return asn1.Marshal(ecPrivateKey{
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Version: 1,
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PrivateKey: key.D.Bytes(),
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NamedCurveOID: oid,
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PublicKey: asn1.BitString{Bytes: elliptic.Marshal(key.Curve, key.X, key.Y)},
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})
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}
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