Openpgp security update (V2) (#31)

* Change keyring unlock functionalities

* Add keyring#Lock, keyring#CheckIntegrity, tests

* Update helpers, fix bugs

* Update go.mod with ProtonMail/crypto commit

* Change key management system

* Clear keys from memory + tests

* Create SessionKey with direct encryption for datapackets. Move symmetrickey to password.

* Fix upstream dependencies

* Update module to V2, documentation

* Add linter

* Add v2 folder to .gitignore

* Minor changes to KeyID getters

* Remove old changelog

* Improve docs, remove compilation script

crypto/session.go

@@ -1,86 +0,0 @@
-package crypto
-
-import (
-	"bytes"
-	"errors"
-	"fmt"
-	"io"
-
-	"golang.org/x/crypto/openpgp/packet"
-)
-
-// RandomToken generated a random token of the same size of the keysize of the default cipher.
-func RandomToken() ([]byte, error) {
-	config := &packet.Config{DefaultCipher: packet.CipherAES256}
-	return RandomTokenSize(config.DefaultCipher.KeySize())
-}
-
-// RandomTokenSize generates a random token with the specified key size
-func RandomTokenSize(size int) ([]byte, error) {
-	config := &packet.Config{DefaultCipher: packet.CipherAES256}
-	symKey := make([]byte, size)
-	if _, err := io.ReadFull(config.Random(), symKey); err != nil {
-		return nil, err
-	}
-	return symKey, nil
-}
-
-// DecryptSessionKey returns the decrypted session key from a binary encrypted session key packet.
-func (keyRing *KeyRing) DecryptSessionKey(keyPacket []byte) (*SymmetricKey, error) {
-	keyReader := bytes.NewReader(keyPacket)
-	packets := packet.NewReader(keyReader)
-
-	var p packet.Packet
-	var err error
-	if p, err = packets.Next(); err != nil {
-		return nil, err
-	}
-
-	ek := p.(*packet.EncryptedKey)
-	var decryptErr error
-	for _, key := range keyRing.entities.DecryptionKeys() {
-		priv := key.PrivateKey
-		if priv.Encrypted {
-			continue
-		}
-
-		if decryptErr = ek.Decrypt(priv, nil); decryptErr == nil {
-			break
-		}
-	}
-
-	if decryptErr != nil {
-		return nil, decryptErr
-	}
-
-	if ek == nil {
-		return nil, errors.New("gopenpgp: unable to decrypt session key")
-	}
-
-	return newSymmetricKeyFromEncrypted(ek)
-}
-
-// EncryptSessionKey encrypts the session key with the unarmored
-// publicKey and returns a binary public-key encrypted session key packet.
-func (keyRing *KeyRing) EncryptSessionKey(sessionSplit *SymmetricKey) ([]byte, error) {
-	outbuf := &bytes.Buffer{}
-
-	cf := sessionSplit.GetCipherFunc()
-
-	var pub *packet.PublicKey
-	for _, e := range keyRing.GetEntities() {
-		if encryptionKey, ok := e.EncryptionKey(getNow()); ok {
-			pub = encryptionKey.PublicKey
-			break
-		}
-	}
-	if pub == nil {
-		return nil, errors.New("cannot set key: no public key available")
-	}
-
-	if err := packet.SerializeEncryptedKey(outbuf, pub, cf, sessionSplit.Key, nil); err != nil {
-		err = fmt.Errorf("gopenpgp: cannot set key: %v", err)
-		return nil, err
-	}
-	return outbuf.Bytes(), nil
-}