112 lines
3.4 KiB
Go
112 lines
3.4 KiB
Go
package pki
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import (
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"bytes"
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"crypto"
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"crypto/rand"
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"encoding/pem"
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"errors"
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"io"
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"github.com/agl/ed25519"
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)
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const (
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PemLabelEd25519 = "ED25519 PRIVATE KEY" // TODO find correct label
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)
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type (
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Ed25519PrivateKey struct {
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private_key [ed25519.PrivateKeySize]byte
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}
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Ed25519PublicKey struct {
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public_key [ed25519.PublicKeySize]byte
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}
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)
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// Create a new private key of type ed25519.
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func NewPrivateKeyEd25519() (*Ed25519PrivateKey, error) {
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_, pr_raw, err := ed25519.GenerateKey(rand.Reader)
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if err != nil {
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return nil, err
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}
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return &Ed25519PrivateKey{*pr_raw}, nil
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}
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// Restore an ed25519 private key from a raw byte stream.
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// TODO does this have to be asn1? all other functions expect asn1
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func LoadPrivateKeyEd25519(raw []byte) (*Ed25519PrivateKey, error) {
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var pr_loaded [ed25519.PrivateKeySize]byte
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length := copy(pr_loaded[:], raw)
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if length != ed25519.PrivateKeySize {
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return nil, errors.New("private key length incorrect")
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}
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return &Ed25519PrivateKey{pr_loaded}, nil
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}
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// TODO implement the raw API for the private key
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func (pr *Ed25519PrivateKey) PrivateKey() crypto.PrivateKey {
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return nil
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}
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// Return the public key for this private key.
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func (pr *Ed25519PrivateKey) Public() PublicKey {
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buf := bytes.NewBufferString(string(pr.private_key[:])) // create a bytes buffer to read the private key
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pu_raw, _, err := ed25519.GenerateKey(buf) // use the already built private key again
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if err != nil {
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return nil
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}
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return &Ed25519PublicKey{*pu_raw}
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}
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// Hash the message given the hash algorythm and sign the hash using the private key.
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func (pr *Ed25519PrivateKey) Sign(message []byte, hash crypto.Hash) ([]byte, error) {
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hashed_message := hash.New()
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hashed_message.Write(message)
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result := ed25519.Sign(&pr.private_key, hashed_message.Sum(nil))[:]
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return result, nil
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}
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// Export the private key into the Pem format.
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func (pr Ed25519PrivateKey) MarshalPem() (io.WriterTo, error) {
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pem_block, err := pr.ToPem()
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if err != nil { // it does not currently return an error, but maybe that will change
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return nil, err
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}
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return marshalledPemBlock(pem.EncodeToMemory(&pem_block)), nil
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}
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func (pr Ed25519PrivateKey) ToPem() (pem.Block, error) {
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return pem.Block{Type: PemLabelEd25519, Bytes: pr.private_key[:]}, nil
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}
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// Load the public key from a raw byte stream.
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// TODO should this be read from ASN.1? All other functions do that.
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func LoadPublicKeyEd25519(raw []byte) (*Ed25519PublicKey, error) {
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var pu_loaded [ed25519.PublicKeySize]byte
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length := copy(pu_loaded[:], raw)
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if length != ed25519.PublicKeySize {
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return nil, errors.New("public key length incorrect")
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}
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return &Ed25519PublicKey{pu_loaded}, nil
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}
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// Export the public key into the pem format.
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func (pu Ed25519PublicKey) MarshalPem() (io.WriterTo, error) {
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pem_block := pem.Block{Type: PemLabelPublic, Bytes: pu.public_key[:]}
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return marshalledPemBlock(pem.EncodeToMemory(&pem_block)), nil
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}
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// Hash the message with the hash algorythm and check the signature against the result.
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func (pu Ed25519PublicKey) Verify(message []byte, signature []byte, hash crypto.Hash) (bool, error) {
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var sig [ed25519.SignatureSize]byte
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length := copy(sig[:], signature)
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if length != ed25519.SignatureSize {
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return false, errors.New("signature does not fit length")
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}
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hashed_message := hash.New()
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hashed_message.Write(message)
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return ed25519.Verify(&pu.public_key, hashed_message.Sum(nil), &sig), nil
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}
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