Add decryptMime and refactor package structure

armor/armor.go

@@ -0,0 +1,133 @@
+package armor
+
+import (
+	"bytes"
+	"io/ioutil"
+	"golang.org/x/crypto/openpgp/armor"
+	"proton/pmcrypto/internal"
+	"golang.org/x/crypto/openpgp/clearsign"
+	"errors"
+	"golang.org/x/crypto/openpgp/packet"
+	"io"
+	"proton/pmcrypto/models"
+)
+
+// ArmorKey make bytes input key to armor format
+func ArmorKey(input []byte) (string, error) {
+	return ArmorWithType(input, PUBLIC_KEY_HEADER)
+}
+
+// ArmorWithType make bytes input to armor format
+func ArmorWithType(input []byte, armorType string) (string, error) {
+	var b bytes.Buffer
+	w, err := armor.Encode(&b, armorType, internal.ArmorHeaders)
+	if err != nil {
+		return "", err
+	}
+	_, err = w.Write(input)
+	if err != nil {
+		return "", err
+	}
+	w.Close()
+	return b.String(), nil
+}
+
+// UnArmor an armored key to bytes key
+func UnArmor(input string) ([]byte, error) {
+	b, err := internal.UnArmor(input)
+	if err != nil {
+		return nil, err
+	}
+	return ioutil.ReadAll(b.Body)
+}
+
+//ReadClearSignedMessage read clear message from a clearsign package
+func ReadClearSignedMessage(signedMessage string) (string, error) {
+	modulusBlock, rest := clearsign.Decode([]byte(signedMessage))
+	if len(rest) != 0 {
+		return "", errors.New("pmapi: extra data after modulus")
+	}
+	return string(modulusBlock.Bytes), nil
+}
+
+
+
+//SeparateKeyAndData ...
+func SplitArmor(encrypted string) (*models.EncryptedSplit, error) {
+
+	var err error
+
+	encryptedRaw, err := UnArmor(encrypted)
+	if err != nil {
+		return nil, err
+	}
+
+	encryptedReader := bytes.NewReader(encryptedRaw)
+
+	//kr *KeyRing, r io.Reader) (key *SymmetricKey, symEncryptedData []byte,
+	packets := packet.NewReader(encryptedReader)
+
+	outSplit := &models.EncryptedSplit{}
+
+	// Save encrypted key and signature apart
+	var ek *packet.EncryptedKey
+	// var decryptErr error
+	for {
+		var p packet.Packet
+		if p, err = packets.Next(); err == io.EOF {
+			err = nil
+			break
+		}
+		switch p := p.(type) {
+		case *packet.EncryptedKey:
+			// We got an encrypted key. Try to decrypt it with each available key
+			if ek != nil && ek.Key != nil {
+				break
+			}
+			ek = p
+			break
+		case *packet.SymmetricallyEncrypted:
+			var packetContents []byte
+			if packetContents, err = ioutil.ReadAll(p.Contents); err != nil {
+				return nil, err
+			}
+
+			encodedLength := encodedLength(len(packetContents) + 1)
+			var symEncryptedData []byte
+			symEncryptedData = append(symEncryptedData, byte(210))
+			symEncryptedData = append(symEncryptedData, encodedLength...)
+			symEncryptedData = append(symEncryptedData, byte(1))
+			symEncryptedData = append(symEncryptedData, packetContents...)
+
+			outSplit.DataPacket = symEncryptedData
+			break
+
+		}
+	}
+
+	var buf bytes.Buffer
+	ek.Serialize(&buf)
+	outSplit.KeyPacket = buf.Bytes()
+
+	return outSplit, err
+}
+
+
+
+//encode length based on 4.2.2. in the RFC
+func encodedLength(length int) (b []byte) {
+	if length < 192 {
+		b = append(b, byte(length))
+	} else if length < 8384 {
+		length = length - 192
+		b = append(b, 192+byte(length>>8))
+		b = append(b, byte(length))
+	} else {
+		b = append(b, byte(255))
+		b = append(b, byte(length>>24))
+		b = append(b, byte(length>>16))
+		b = append(b, byte(length>>8))
+		b = append(b, byte(length))
+	}
+	return
+}