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// Code generated from pkg.templ.go. DO NOT EDIT.
// Package sikep751 is deprecated, it implements the key encapsulation mechanism SIKEp751.
//
// # DEPRECATION NOTICE
//
// SIDH and SIKE are deprecated as were shown vulnerable to a key recovery
// attack by Castryck-Decru's paper (https://eprint.iacr.org/2022/975). New
// systems should not rely on this package. This package is frozen.
package sikep751
import (
"bytes"
cryptoRand "crypto/rand"
"crypto/subtle"
"io"
"github.com/cloudflare/circl/dh/sidh"
"github.com/cloudflare/circl/internal/sha3"
"github.com/cloudflare/circl/kem"
)
// Deprecated: not cryptographically secure.
type PrivateKey struct {
sk *sidh.PrivateKey
pk *sidh.PublicKey
}
// Deprecated: not cryptographically secure.
type PublicKey sidh.PublicKey
const (
SeedSize = 32
EncapsulationSeedSize = 32
)
type scheme struct{}
var sch kem.Scheme = &scheme{}
// Scheme returns a KEM interface.
//
// Deprecated: not cryptographically secure.
func Scheme() kem.Scheme { return sch }
var params *sidh.KEM
func (*scheme) Name() string { return "SIKEp751" }
func (*scheme) PublicKeySize() int { return params.PublicKeySize() }
func (*scheme) PrivateKeySize() int { return params.PrivateKeySize() }
func (*scheme) SeedSize() int { return SeedSize }
func (*scheme) SharedKeySize() int { return params.SharedSecretSize() }
func (*scheme) CiphertextSize() int { return params.CiphertextSize() }
func (*scheme) EncapsulationSeedSize() int { return EncapsulationSeedSize }
func (sk *PrivateKey) Scheme() kem.Scheme { return sch }
func (pk *PublicKey) Scheme() kem.Scheme { return sch }
func (sk *PrivateKey) MarshalBinary() ([]byte, error) {
ret := make([]byte, sk.sk.Size())
sk.sk.Export(ret)
return ret, nil
}
func (sk *PrivateKey) Equal(other kem.PrivateKey) bool {
oth, ok := other.(*PrivateKey)
if !ok {
return false
}
a, _ := sk.MarshalBinary()
b, _ := oth.MarshalBinary()
return subtle.ConstantTimeCompare(a, b) == 1
}
func (sk *PrivateKey) Public() kem.PublicKey {
if sk.pk == nil {
sk.pk = sidh.NewPublicKey(sidh.Fp751, sidh.KeyVariantSike)
sk.sk.GeneratePublicKey(sk.pk)
}
return (*PublicKey)(sk.pk)
}
func (pk *PublicKey) Equal(other kem.PublicKey) bool {
oth, ok := other.(*PublicKey)
if !ok {
return false
}
a, _ := pk.MarshalBinary()
b, _ := oth.MarshalBinary()
return bytes.Equal(a, b)
}
func (pk *PublicKey) MarshalBinary() ([]byte, error) {
cpk := (*sidh.PublicKey)(pk)
ret := make([]byte, cpk.Size())
cpk.Export(ret)
return ret, nil
}
// Deprecated: not cryptographically secure.
func GenerateKeyPair(rand io.Reader) (kem.PublicKey, kem.PrivateKey, error) {
sk := sidh.NewPrivateKey(sidh.Fp751, sidh.KeyVariantSike)
if err := sk.Generate(rand); err != nil {
return nil, nil, err
}
priv := &PrivateKey{sk: sk}
return priv.Public(), priv, nil
}
func (*scheme) GenerateKeyPair() (kem.PublicKey, kem.PrivateKey, error) {
return GenerateKeyPair(cryptoRand.Reader)
}
func (*scheme) DeriveKeyPair(seed []byte) (kem.PublicKey, kem.PrivateKey) {
if len(seed) != SeedSize {
panic(kem.ErrSeedSize)
}
h := sha3.NewShake256()
_, _ = h.Write(seed[:])
pk, sk, err := GenerateKeyPair(&h)
if err != nil {
panic(err)
}
return pk, sk
}
func (sch *scheme) Encapsulate(pk kem.PublicKey) (ct []byte, ss []byte, err error) {
var seed [EncapsulationSeedSize]byte
if _, err := cryptoRand.Read(seed[:]); err != nil {
return nil, nil, err
}
return sch.EncapsulateDeterministically(pk, seed[:])
}
func (sch *scheme) EncapsulateDeterministically(pk kem.PublicKey, seed []byte) (ct []byte, ss []byte, err error) {
if len(seed) != EncapsulationSeedSize {
return nil, nil, kem.ErrSeedSize
}
pub, ok := pk.(*PublicKey)
if !ok {
return nil, nil, kem.ErrTypeMismatch
}
ct = make([]byte, sch.CiphertextSize())
ss = make([]byte, sch.SharedKeySize())
h := sha3.NewShake256()
_, _ = h.Write(seed[:])
ctx := sidh.NewSike751(&h)
if err := ctx.Encapsulate(ct, ss, (*sidh.PublicKey)(pub)); err != nil {
return nil, nil, err
}
return ct, ss, nil
}
func (sch *scheme) Decapsulate(sk kem.PrivateKey, ct []byte) ([]byte, error) {
if len(ct) != sch.CiphertextSize() {
return nil, kem.ErrCiphertextSize
}
priv, ok := sk.(*PrivateKey)
if !ok {
return nil, kem.ErrTypeMismatch
}
sikePub := sidh.NewPublicKey(sidh.Fp751, sidh.KeyVariantSike)
priv.sk.GeneratePublicKey(sikePub)
ss := make([]byte, sch.SharedKeySize())
ctx := sidh.NewSike751(nil)
if err := ctx.Decapsulate(ss, priv.sk, sikePub, ct); err != nil {
return nil, err
}
return ss, nil
}
func (sch *scheme) UnmarshalBinaryPublicKey(buf []byte) (kem.PublicKey, error) {
if len(buf) != sch.PublicKeySize() {
return nil, kem.ErrPubKeySize
}
pk := sidh.NewPublicKey(sidh.Fp751, sidh.KeyVariantSike)
if err := pk.Import(buf); err != nil {
return nil, err
}
return (*PublicKey)(pk), nil
}
func (sch *scheme) UnmarshalBinaryPrivateKey(buf []byte) (kem.PrivateKey, error) {
if len(buf) != sch.PrivateKeySize() {
return nil, kem.ErrPrivKeySize
}
sk := sidh.NewPrivateKey(sidh.Fp751, sidh.KeyVariantSike)
if err := sk.Import(buf); err != nil {
return nil, err
}
return &PrivateKey{sk: sk}, nil
}
func init() {
params = sidh.NewSike751(nil)
}
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