Add decryptMime and refactor package structure

crypto/attachment.go

@@ -0,0 +1,171 @@
+package crypto
+
+import (
+	"bytes"
+	"io"
+	"io/ioutil"
+
+	"golang.org/x/crypto/openpgp"
+	armorUtils "proton/pmcrypto/armor"
+	"golang.org/x/crypto/openpgp/packet"
+		"proton/pmcrypto/internal"
+	"golang.org/x/crypto/openpgp/armor"
+	"proton/pmcrypto/models"
+)
+
+//EncryptAttachmentBinKey ...
+func (pm *PmCrypto) EncryptAttachmentBinKey(plainData []byte, fileName string, publicKey []byte) (*models.EncryptedSplit, error) {
+
+	var outBuf bytes.Buffer
+	w, err := armor.Encode(&outBuf, armorUtils.MESSAGE_HEADER, internal.ArmorHeaders)
+	if err != nil {
+		return nil, err
+	}
+
+	pubKeyReader := bytes.NewReader(publicKey)
+	pubKeyEntries, err := openpgp.ReadKeyRing(pubKeyReader)
+	if err != nil {
+		return nil, err
+	}
+	hints := &openpgp.FileHints{
+		FileName: fileName,
+	}
+
+	config := &packet.Config{
+		DefaultCipher: packet.CipherAES256,
+		Time:          pm.getTimeGenerator(),
+	}
+
+	ew, err := openpgp.Encrypt(w, pubKeyEntries, nil, hints, config)
+
+	_, _ = ew.Write(plainData)
+	ew.Close()
+	w.Close()
+
+	split, err := armorUtils.SplitArmor(outBuf.String())
+	if err != nil {
+		return nil, err
+	}
+	split.Algo = "aes256"
+	return split, nil
+}
+
+//EncryptAttachment ...
+func (pm *PmCrypto) EncryptAttachment(plainData []byte, fileName string, publicKey string) (*models.EncryptedSplit, error) {
+	rawPubKey, err := armorUtils.UnArmor(publicKey)
+	if err != nil {
+		return nil, err
+	}
+	return pm.EncryptAttachmentBinKey(plainData, fileName, rawPubKey)
+}
+
+//DecryptAttachmentBinKey ...
+//keyPacket
+//dataPacket
+//privateKeys could be mutiple private keys
+func (pm *PmCrypto) DecryptAttachmentBinKey(keyPacket []byte, dataPacket []byte, privateKeys []byte, passphrase string) ([]byte, error) {
+	privKeyRaw := bytes.NewReader(privateKeys)
+	privKeyEntries, err := openpgp.ReadKeyRing(privKeyRaw)
+	if err != nil {
+		return nil, err
+	}
+
+	rawPwd := []byte(passphrase)
+	for _, e := range privKeyEntries {
+
+		if e.PrivateKey != nil && e.PrivateKey.Encrypted {
+			e.PrivateKey.Decrypt(rawPwd)
+		}
+
+		for _, sub := range e.Subkeys {
+			if sub.PrivateKey != nil && sub.PrivateKey.Encrypted {
+				sub.PrivateKey.Decrypt(rawPwd)
+			}
+		}
+	}
+
+	keyReader := bytes.NewReader(keyPacket)
+	dataReader := bytes.NewReader(dataPacket)
+
+	encryptedReader := io.MultiReader(keyReader, dataReader)
+
+	config := &packet.Config{ Time: pm.getTimeGenerator() }
+
+	md, err := openpgp.ReadMessage(encryptedReader, privKeyEntries, nil, config)
+	if err != nil {
+		return nil, err
+	}
+
+	decrypted := md.UnverifiedBody
+	b, err := ioutil.ReadAll(decrypted)
+	if err != nil {
+		return nil, err
+	}
+
+	return b, nil
+}
+
+//DecryptAttachment ...
+func (pm *PmCrypto) DecryptAttachment(keyPacket []byte, dataPacket []byte, privateKey string, passphrase string) ([]byte, error) {
+	rawPrivKey, err := armorUtils.UnArmor(privateKey)
+	if err != nil {
+		return nil, err
+	}
+	return pm.DecryptAttachmentBinKey(keyPacket, dataPacket, rawPrivKey, passphrase)
+}
+
+//EncryptAttachmentWithPassword ...
+func (pm *PmCrypto) EncryptAttachmentWithPassword(plainData []byte, password string) (string, error) {
+
+	var outBuf bytes.Buffer
+	w, err := armor.Encode(&outBuf, armorUtils.MESSAGE_HEADER, internal.ArmorHeaders)
+	if err != nil {
+		return "", err
+	}
+
+	config := &packet.Config{ Time: pm.getTimeGenerator() }
+
+	plaintext, err := openpgp.SymmetricallyEncrypt(w, []byte(password), nil, config)
+	if err != nil {
+		return "", err
+	}
+
+	_, err = plaintext.Write(plainData)
+	if err != nil {
+		return "", err
+	}
+	err = plaintext.Close()
+	if err != nil {
+		return "", err
+	}
+	w.Close()
+
+	return outBuf.String(), nil
+}
+
+//DecryptAttachmentWithPassword ...
+func (pm *PmCrypto) DecryptAttachmentWithPassword(keyPacket []byte, dataPacket []byte, password string) ([]byte, error) {
+
+	encrypted := append(keyPacket, dataPacket...)
+
+	encryptedReader := bytes.NewReader(encrypted)
+
+	var prompt = func(keys []openpgp.Key, symmetric bool) ([]byte, error) {
+		return []byte(password), nil
+	}
+
+	config := &packet.Config{ Time: pm.getTimeGenerator() }
+
+	md, err := openpgp.ReadMessage(encryptedReader, nil, prompt, config)
+	if err != nil {
+		return nil, err
+	}
+
+	messageBuf := bytes.NewBuffer(nil)
+	_, err = io.Copy(messageBuf, md.UnverifiedBody)
+	if err != nil {
+		return nil, err
+	}
+
+	return messageBuf.Bytes(), nil
+}