refactor: refactor pgp implementation

This commit refactors the internal PGP implementation to make way for
GPG integration.

Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>
Acked-by: Koni Marti <koni.marti@gmail.com>
Acked-by: Robin Jarry <robin@jarry.cc>

15 files changed, 356 insertions, 193 deletions

diff --git a/aerc.go b/aerc.go
index f9a19a31..57259be1 100644
--- a/aerc.go
+++ b/aerc.go
@@ -22,6 +22,7 @@ import (
 	"git.sr.ht/~rjarry/aerc/commands/terminal"
 	"git.sr.ht/~rjarry/aerc/config"
 	"git.sr.ht/~rjarry/aerc/lib"
+	"git.sr.ht/~rjarry/aerc/lib/crypto"
 	"git.sr.ht/~rjarry/aerc/lib/templates"
 	libui "git.sr.ht/~rjarry/aerc/lib/ui"
 	"git.sr.ht/~rjarry/aerc/logging"
@@ -168,7 +169,11 @@ func main() {
 
 	deferLoop := make(chan struct{})
 
-	aerc = widgets.NewAerc(conf, logger, func(cmd []string) error {
+	c := crypto.New(conf.General.PgpProvider)
+	c.Init(logger)
+	defer c.Close()
+
+	aerc = widgets.NewAerc(conf, logger, c, func(cmd []string) error {
 		return execCommand(aerc, ui, cmd)
 	}, func(cmd string) []string {
 		return getCompletions(aerc, cmd)
@@ -188,10 +193,6 @@ func main() {
 		ui.EnableMouse()
 	}
 
-	logger.Println("Initializing PGP keyring")
-	lib.InitKeyring()
-	defer lib.UnlockKeyring()
-
 	logger.Println("Starting Unix server")
 	as, err := lib.StartServer(logger)
 	if err != nil {
diff --git a/commands/account/view.go b/commands/account/view.go
index 53ad2678..8537d331 100644
--- a/commands/account/view.go
+++ b/commands/account/view.go
@@ -45,7 +45,7 @@ func (ViewMessage) Execute(aerc *widgets.Aerc, args []string) error {
 		aerc.PushError(msg.Error.Error())
 		return nil
 	}
-	lib.NewMessageStoreView(msg, store, aerc.DecryptKeys,
+	lib.NewMessageStoreView(msg, store, aerc.Crypto, aerc.DecryptKeys,
 		func(view lib.MessageView, err error) {
 			if err != nil {
 				aerc.PushError(err.Error())
diff --git a/commands/msg/delete.go b/commands/msg/delete.go
index 5eb622de..d26169f9 100644
--- a/commands/msg/delete.go
+++ b/commands/msg/delete.go
@@ -68,7 +68,7 @@ func (Delete) Execute(aerc *widgets.Aerc, args []string) error {
 				acct.Messages().Invalidate()
 				return nil
 			}
-			lib.NewMessageStoreView(next, store, aerc.DecryptKeys,
+			lib.NewMessageStoreView(next, store, aerc.Crypto, aerc.DecryptKeys,
 				func(view lib.MessageView, err error) {
 					if err != nil {
 						aerc.PushError(err.Error())
diff --git a/commands/msgview/next.go b/commands/msgview/next.go
index 742bc665..928b9fbc 100644
--- a/commands/msgview/next.go
+++ b/commands/msgview/next.go
@@ -42,7 +42,7 @@ func (NextPrevMsg) Execute(aerc *widgets.Aerc, args []string) error {
 		aerc.RemoveTab(mv)
 		return nil
 	}
-	lib.NewMessageStoreView(nextMsg, store, aerc.DecryptKeys,
+	lib.NewMessageStoreView(nextMsg, store, aerc.Crypto, aerc.DecryptKeys,
 		func(view lib.MessageView, err error) {
 			if err != nil {
 				aerc.PushError(err.Error())
diff --git a/config/config.go b/config/config.go
index 048dd238..0c9a40fd 100644
--- a/config/config.go
+++ b/config/config.go
@@ -27,6 +27,7 @@ import (
 
 type GeneralConfig struct {
 	DefaultSavePath    string `ini:"default-save-path"`
+	PgpProvider        string `ini:"pgp-provider"`
 	UnsafeAccountsConf bool   `ini:"unsafe-accounts-conf"`
 }
 
@@ -579,6 +580,21 @@ func validateBorderChars(section *ini.Section, config *UIConfig) error {
 	return nil
 }
 
+func validatePgpProvider(section *ini.Section) error {
+	m := map[string]bool{
+		"internal": true,
+	}
+	for key, val := range section.KeysHash() {
+		switch key {
+		case "pgp-provider":
+			if !m[strings.ToLower(val)] {
+				return fmt.Errorf("%v must be 'internal'", key)
+			}
+		}
+	}
+	return nil
+}
+
 func LoadConfigFromFile(root *string, logger *log.Logger) (*AercConfig, error) {
 	if root == nil {
 		_root := path.Join(xdg.ConfigHome(), "aerc")
@@ -618,6 +634,7 @@ func LoadConfigFromFile(root *string, logger *log.Logger) (*AercConfig, error) {
 		Ini: file,
 
 		General: GeneralConfig{
+			PgpProvider:        "internal",
 			UnsafeAccountsConf: false,
 		},
 
@@ -704,6 +721,9 @@ func LoadConfigFromFile(root *string, logger *log.Logger) (*AercConfig, error) {
 		if err := ui.MapTo(&config.General); err != nil {
 			return nil, err
 		}
+		if err := validatePgpProvider(ui); err != nil {
+			return nil, err
+		}
 	}
 
 	filename = path.Join(*root, "accounts.conf")
diff --git a/lib/crypto/crypto.go b/lib/crypto/crypto.go
new file mode 100644
index 00000000..47cb9544
--- /dev/null
+++ b/lib/crypto/crypto.go
@@ -0,0 +1,28 @@
+package crypto
+
+import (
+	"bytes"
+	"io"
+	"log"
+
+	"git.sr.ht/~rjarry/aerc/lib/crypto/pgp"
+	"git.sr.ht/~rjarry/aerc/models"
+	"github.com/ProtonMail/go-crypto/openpgp"
+	"github.com/emersion/go-message/mail"
+)
+
+type Provider interface {
+	Decrypt(io.Reader, openpgp.PromptFunction) (*models.MessageDetails, error)
+	Encrypt(*bytes.Buffer, []string, string, openpgp.PromptFunction, *mail.Header) (io.WriteCloser, error)
+	Sign(*bytes.Buffer, string, openpgp.PromptFunction, *mail.Header) (io.WriteCloser, error)
+	ImportKeys(io.Reader) error
+	Init(*log.Logger) error
+	Close()
+}
+
+func New(s string) Provider {
+	switch s {
+	default:
+		return &pgp.Mail{}
+	}
+}
diff --git a/lib/crypto/pgp/pgp.go b/lib/crypto/pgp/pgp.go
new file mode 100644
index 00000000..70a003a0
--- /dev/null
+++ b/lib/crypto/pgp/pgp.go
@@ -0,0 +1,240 @@
+package pgp
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+	"path"
+	"strings"
+	"time"
+
+	"git.sr.ht/~rjarry/aerc/models"
+	"github.com/ProtonMail/go-crypto/openpgp"
+	"github.com/ProtonMail/go-crypto/openpgp/packet"
+	"github.com/emersion/go-message/mail"
+	"github.com/emersion/go-pgpmail"
+	"github.com/kyoh86/xdg"
+	"github.com/pkg/errors"
+)
+
+type Mail struct {
+	logger *log.Logger
+}
+
+var (
+	Keyring openpgp.EntityList
+
+	locked bool
+)
+
+func (m *Mail) Init(l *log.Logger) error {
+	m.logger = l
+	m.logger.Println("Initializing PGP keyring")
+	os.MkdirAll(path.Join(xdg.DataHome(), "aerc"), 0700)
+
+	lockpath := path.Join(xdg.DataHome(), "aerc", "keyring.lock")
+	lockfile, err := os.OpenFile(lockpath, os.O_CREATE|os.O_EXCL, 0600)
+	if err != nil {
+		// TODO: Consider connecting to main process over IPC socket
+		locked = false
+	} else {
+		locked = true
+		lockfile.Close()
+	}
+
+	keypath := path.Join(xdg.DataHome(), "aerc", "keyring.asc")
+	keyfile, err := os.Open(keypath)
+	if os.IsNotExist(err) {
+		return nil
+	} else if err != nil {
+		panic(err)
+	}
+	defer keyfile.Close()
+
+	Keyring, err = openpgp.ReadKeyRing(keyfile)
+	if err != nil {
+		panic(err)
+	}
+	return nil
+}
+
+func (m *Mail) Close() {
+	if !locked {
+		return
+	}
+	lockpath := path.Join(xdg.DataHome(), "aerc", "keyring.lock")
+	os.Remove(lockpath)
+}
+
+func (m *Mail) getEntityByEmail(email string) (e *openpgp.Entity, err error) {
+	for _, entity := range Keyring {
+		ident := entity.PrimaryIdentity()
+		if ident != nil && ident.UserId.Email == email {
+			return entity, nil
+		}
+	}
+	return nil, fmt.Errorf("entity not found in keyring")
+}
+
+func (m *Mail) getSignerEntityByEmail(email string) (e *openpgp.Entity, err error) {
+	for _, key := range Keyring.DecryptionKeys() {
+		if key.Entity == nil {
+			continue
+		}
+		ident := key.Entity.PrimaryIdentity()
+		if ident != nil && ident.UserId.Email == email {
+			return key.Entity, nil
+		}
+	}
+	return nil, fmt.Errorf("entity not found in keyring")
+}
+
+func (m *Mail) Decrypt(r io.Reader, decryptKeys openpgp.PromptFunction) (*models.MessageDetails, error) {
+	md := new(models.MessageDetails)
+
+	pgpReader, err := pgpmail.Read(r, Keyring, decryptKeys, nil)
+	if err != nil {
+		return nil, err
+	}
+	if pgpReader.MessageDetails.IsEncrypted {
+		md.IsEncrypted = true
+		md.DecryptedWith = pgpReader.MessageDetails.DecryptedWith.Entity.PrimaryIdentity().Name
+		md.DecryptedWithKeyId = pgpReader.MessageDetails.DecryptedWith.PublicKey.KeyId
+	}
+	if pgpReader.MessageDetails.IsSigned {
+		// we should consume the UnverifiedBody until EOF in order
+		// to get the correct signature data
+		data, err := ioutil.ReadAll(pgpReader.MessageDetails.UnverifiedBody)
+		if err != nil {
+			return nil, err
+		}
+		pgpReader.MessageDetails.UnverifiedBody = bytes.NewReader(data)
+
+		md.IsSigned = true
+		md.SignedBy = ""
+		md.SignedByKeyId = pgpReader.MessageDetails.SignedByKeyId
+		md.SignatureValidity = models.Valid
+		if pgpReader.MessageDetails.SignatureError != nil {
+			md.SignatureError = pgpReader.MessageDetails.SignatureError.Error()
+			md.SignatureValidity = handleSignatureError(md.SignatureError)
+		}
+		if pgpReader.MessageDetails.SignedBy != nil {
+			md.SignedBy = pgpReader.MessageDetails.SignedBy.Entity.PrimaryIdentity().Name
+		}
+	}
+	md.Body = pgpReader.MessageDetails.UnverifiedBody
+	return md, nil
+}
+
+func (m *Mail) ImportKeys(r io.Reader) error {
+	keys, err := openpgp.ReadKeyRing(r)
+	if err != nil {
+		return err
+	}
+	Keyring = append(Keyring, keys...)
+	if locked {
+		keypath := path.Join(xdg.DataHome(), "aerc", "keyring.asc")
+		keyfile, err := os.OpenFile(keypath, os.O_CREATE|os.O_APPEND, 0600)
+		if err != nil {
+			return err
+		}
+		defer keyfile.Close()
+
+		for _, key := range keys {
+			if key.PrivateKey != nil {
+				err = key.SerializePrivate(keyfile, &packet.Config{})
+			} else {
+				err = key.Serialize(keyfile)
+			}
+			if err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func (m *Mail) Encrypt(buf *bytes.Buffer, rcpts []string, signerEmail string, decryptKeys openpgp.PromptFunction, header *mail.Header) (io.WriteCloser, error) {
+	var err error
+	var to []*openpgp.Entity
+	var signer *openpgp.Entity
+	if signerEmail != "" {
+		signer, err = m.getSigner(signerEmail, decryptKeys)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	for _, rcpt := range rcpts {
+		toEntity, err := m.getEntityByEmail(rcpt)
+		if err != nil {
+			return nil, errors.Wrap(err, "no key for "+rcpt)
+		}
+		to = append(to, toEntity)
+	}
+
+	cleartext, err := pgpmail.Encrypt(buf, header.Header.Header,
+		to, signer, nil)
+	if err != nil {
+		return nil, err
+	}
+	return cleartext, nil
+}
+
+func (m *Mail) Sign(buf *bytes.Buffer, signerEmail string, decryptKeys openpgp.PromptFunction, header *mail.Header) (io.WriteCloser, error) {
+	var err error
+	var signer *openpgp.Entity
+	if signerEmail != "" {
+		signer, err = m.getSigner(signerEmail, decryptKeys)
+		if err != nil {
+			return nil, err
+		}
+	}
+	cleartext, err := pgpmail.Sign(buf, header.Header.Header, signer, nil)
+	if err != nil {
+		return nil, err
+	}
+	return cleartext, nil
+}
+
+func (m *Mail) getSigner(signerEmail string, decryptKeys openpgp.PromptFunction) (signer *openpgp.Entity, err error) {
+	if err != nil {
+		return nil, err
+	}
+	signer, err = m.getSignerEntityByEmail(signerEmail)
+	if err != nil {
+		return nil, err
+	}
+
+	key, ok := signer.SigningKey(time.Now())
+	if !ok {
+		return nil, fmt.Errorf("no signing key found for %s", signerEmail)
+	}
+
+	if !key.PrivateKey.Encrypted {
+		return signer, nil
+	}
+
+	_, err = decryptKeys([]openpgp.Key{key}, false)
+	if err != nil {
+		return nil, err
+	}
+
+	return signer, nil
+}
+
+func handleSignatureError(e string) models.SignatureValidity {
+	if e == "openpgp: signature made by unknown entity" {
+		return models.UnknownEntity
+	}
+	if strings.HasPrefix(e, "pgpmail: unsupported micalg") {
+		return models.UnsupportedMicalg
+	}
+	if strings.HasPrefix(e, "pgpmail") {
+		return models.InvalidSignature
+	}
+	return models.UnknownValidity
+}
diff --git a/lib/keystore.go b/lib/keystore.go
deleted file mode 100644
index 0b9d41af..00000000
--- a/lib/keystore.go
+++ /dev/null
@@ -1,105 +0,0 @@
-package lib
-
-import (
-	"fmt"
-	"io"
-	"os"
-	"path"
-
-	"github.com/ProtonMail/go-crypto/openpgp"
-	"github.com/ProtonMail/go-crypto/openpgp/packet"
-	"github.com/kyoh86/xdg"
-)
-
-var (
-	Keyring openpgp.EntityList
-
-	locked bool
-)
-
-func InitKeyring() {
-	os.MkdirAll(path.Join(xdg.DataHome(), "aerc"), 0700)
-
-	lockpath := path.Join(xdg.DataHome(), "aerc", "keyring.lock")
-	lockfile, err := os.OpenFile(lockpath, os.O_CREATE|os.O_EXCL, 0600)
-	if err != nil {
-		// TODO: Consider connecting to main process over IPC socket
-		locked = false
-	} else {
-		locked = true
-		lockfile.Close()
-	}
-
-	keypath := path.Join(xdg.DataHome(), "aerc", "keyring.asc")
-	keyfile, err := os.Open(keypath)
-	if os.IsNotExist(err) {
-		return
-	} else if err != nil {
-		panic(err)
-	}
-	defer keyfile.Close()
-
-	Keyring, err = openpgp.ReadKeyRing(keyfile)
-	if err != nil {
-		panic(err)
-	}
-}
-
-func UnlockKeyring() {
-	if !locked {
-		return
-	}
-	lockpath := path.Join(xdg.DataHome(), "aerc", "keyring.lock")
-	os.Remove(lockpath)
-}
-
-func GetEntityByEmail(email string) (e *openpgp.Entity, err error) {
-	for _, entity := range Keyring {
-		ident := entity.PrimaryIdentity()
-		if ident != nil && ident.UserId.Email == email {
-			return entity, nil
-		}
-	}
-	return nil, fmt.Errorf("entity not found in keyring")
-}
-
-func GetSignerEntityByEmail(email string) (e *openpgp.Entity, err error) {
-	for _, key := range Keyring.DecryptionKeys() {
-		if key.Entity == nil {
-			continue
-		}
-		ident := key.Entity.PrimaryIdentity()
-		if ident != nil && ident.UserId.Email == email {
-			return key.Entity, nil
-		}
-	}
-	return nil, fmt.Errorf("entity not found in keyring")
-}
-
-func ImportKeys(r io.Reader) error {
-	keys, err := openpgp.ReadKeyRing(r)
-	if err != nil {
-		return err
-	}
-	Keyring = append(Keyring, keys...)
-	if locked {
-		keypath := path.Join(xdg.DataHome(), "aerc", "keyring.asc")
-		keyfile, err := os.OpenFile(keypath, os.O_CREATE|os.O_APPEND, 0600)
-		if err != nil {
-			return err
-		}
-		defer keyfile.Close()
-
-		for _, key := range keys {
-			if key.PrivateKey != nil {
-				err = key.SerializePrivate(keyfile, &packet.Config{})
-			} else {
-				err = key.Serialize(keyfile)
-			}
-			if err != nil {
-				return err
-			}
-		}
-	}
-	return nil
-}
diff --git a/lib/messageview.go b/lib/messageview.go
index f221fb2c..a1797d53 100644
--- a/lib/messageview.go
+++ b/lib/messageview.go
@@ -8,8 +8,8 @@ import (
 	"github.com/ProtonMail/go-crypto/openpgp"
 	"github.com/emersion/go-message"
 	_ "github.com/emersion/go-message/charset"
-	"github.com/emersion/go-pgpmail"
 
+	"git.sr.ht/~rjarry/aerc/lib/crypto"
 	"git.sr.ht/~rjarry/aerc/models"
 	"git.sr.ht/~rjarry/aerc/worker/lib"
 	"git.sr.ht/~rjarry/aerc/worker/types"
@@ -30,7 +30,7 @@ type MessageView interface {
 	// Fetches a specific body part for this message
 	FetchBodyPart(part []int, cb func(io.Reader))
 
-	PGPDetails() *openpgp.MessageDetails
+	MessageDetails() *models.MessageDetails
 }
 
 func usePGP(info *models.BodyStructure) bool {
@@ -56,12 +56,12 @@ type MessageStoreView struct {
 	messageInfo   *models.MessageInfo
 	messageStore  *MessageStore
 	message       []byte
-	details       *openpgp.MessageDetails
+	details       *models.MessageDetails
 	bodyStructure *models.BodyStructure
 }
 
 func NewMessageStoreView(messageInfo *models.MessageInfo,
-	store *MessageStore, decryptKeys openpgp.PromptFunction,
+	store *MessageStore, pgp crypto.Provider, decryptKeys openpgp.PromptFunction,
 	cb func(MessageView, error)) {
 
 	msv := &MessageStoreView{messageInfo, store,
@@ -70,12 +70,12 @@ func NewMessageStoreView(messageInfo *models.MessageInfo,
 	if usePGP(messageInfo.BodyStructure) {
 		store.FetchFull([]uint32{messageInfo.Uid}, func(fm *types.FullMessage) {
 			reader := lib.NewCRLFReader(fm.Content.Reader)
-			pgpReader, err := pgpmail.Read(reader, Keyring, decryptKeys, nil)
+			md, err := pgp.Decrypt(reader, decryptKeys)
 			if err != nil {
 				cb(nil, err)
 				return
 			}
-			msv.message, err = ioutil.ReadAll(pgpReader.MessageDetails.UnverifiedBody)
+			msv.message, err = ioutil.ReadAll(md.Body)
 			if err != nil {
 				cb(nil, err)
 				return
@@ -91,7 +91,7 @@ func NewMessageStoreView(messageInfo *models.MessageInfo,
 				return
 			}
 			msv.bodyStructure = bs
-			msv.details = pgpReader.MessageDetails
+			msv.details = md
 			cb(msv, nil)
 		})
 	} else {
@@ -112,7 +112,7 @@ func (msv *MessageStoreView) Store() *MessageStore {
 	return msv.messageStore
 }
 
-func (msv *MessageStoreView) PGPDetails() *openpgp.MessageDetails {
+func (msv *MessageStoreView) MessageDetails() *models.MessageDetails {
 	return msv.details
 }
 
diff --git a/models/models.go b/models/models.go
index 4087c9d3..96683f29 100644
--- a/models/models.go
+++ b/models/models.go
@@ -185,3 +185,27 @@ type OriginalMail struct {
 	MIMEType      string
 	RFC822Headers *mail.Header
 }
+
+type SignatureValidity int32
+
+const (
+	UnknownValidity SignatureValidity = iota
+	Valid
+	InvalidSignature
+	UnknownEntity
+	UnsupportedMicalg
+	MicalgMismatch
+)
+
+type MessageDetails struct {
+	IsEncrypted        bool
+	IsSigned           bool
+	SignedBy           string // Primary identity of signing key
+	SignedByKeyId      uint64
+	SignatureValidity  SignatureValidity
+	SignatureError     string
+	DecryptedWith      string // Primary Identity of decryption key
+	DecryptedWithKeyId uint64 // Public key id of decryption key
+	Body               io.Reader
+	Micalg             string
+}
diff --git a/widgets/aerc.go b/widgets/aerc.go
index 717547dc..0b4e36dd 100644
--- a/widgets/aerc.go
+++ b/widgets/aerc.go
@@ -16,6 +16,7 @@ import (
 
 	"git.sr.ht/~rjarry/aerc/config"
 	"git.sr.ht/~rjarry/aerc/lib"
+	"git.sr.ht/~rjarry/aerc/lib/crypto"
 	"git.sr.ht/~rjarry/aerc/lib/ui"
 	"git.sr.ht/~rjarry/aerc/models"
 )
@@ -38,6 +39,8 @@ type Aerc struct {
 	ui          *ui.UI
 	beep        func() error
 	dialog      ui.DrawableInteractive
+
+	Crypto crypto.Provider
 }
 
 type Choice struct {
@@ -47,9 +50,9 @@ type Choice struct {
 }
 
 func NewAerc(conf *config.AercConfig, logger *log.Logger,
-	cmd func(cmd []string) error, complete func(cmd string) []string,
-	cmdHistory lib.History, deferLoop chan struct{},
-) *Aerc {
+	crypto crypto.Provider, cmd func(cmd []string) error,
+	complete func(cmd string) []string, cmdHistory lib.History,
+	deferLoop chan struct{}) *Aerc {
 	tabs := ui.NewTabs(&conf.Ui)
 
 	statusbar := ui.NewStack(conf.Ui)
@@ -79,6 +82,7 @@ func NewAerc(conf *config.AercConfig, logger *log.Logger,
 		statusline: statusline,
 		prompts:    ui.NewStack(conf.Ui),
 		tabs:       tabs,
+		Crypto:     crypto,
 	}
 
 	statusline.SetAerc(aerc)
diff --git a/widgets/compose.go b/widgets/compose.go
index 5f2c7069..6298be3a 100644
--- a/widgets/compose.go
+++ b/widgets/compose.go
@@ -15,9 +15,7 @@ import (
 	"strings"
 	"time"
 
-	"github.com/ProtonMail/go-crypto/openpgp"
 	"github.com/emersion/go-message/mail"
-	"github.com/emersion/go-pgpmail"
 	"github.com/gdamore/tcell/v2"
 	"github.com/mattn/go-runewidth"
 	"github.com/mitchellh/go-homedir"
@@ -25,7 +23,6 @@ import (
 
 	"git.sr.ht/~rjarry/aerc/completer"
 	"git.sr.ht/~rjarry/aerc/config"
-	"git.sr.ht/~rjarry/aerc/lib"
 	"git.sr.ht/~rjarry/aerc/lib/format"
 	"git.sr.ht/~rjarry/aerc/lib/templates"
 	"git.sr.ht/~rjarry/aerc/lib/ui"
@@ -455,38 +452,27 @@ func (c *Composer) WriteMessage(header *mail.Header, writer io.Writer) error {
 		var cleartext io.WriteCloser
 		var err error
 
-		var signer *openpgp.Entity
+		var signerEmail string
 		if c.sign {
-			signer, err = getSigner(c)
+			signerEmail, err = getSenderEmail(c)
 			if err != nil {
 				return err
 			}
 		} else {
-			signer = nil
+			signerEmail = ""
 		}
 
 		if c.encrypt {
-			var to []*openpgp.Entity
 			rcpts, err := getRecipientsEmail(c)
 			if err != nil {
 				return err
 			}
-			for _, rcpt := range rcpts {
-				toEntity, err := lib.GetEntityByEmail(rcpt)
-				if err != nil {
-					return errors.Wrap(err, "no key for "+rcpt)
-				}
-				to = append(to, toEntity)
-			}
-			cleartext, err = pgpmail.Encrypt(&buf, header.Header.Header,
-				to, signer, nil)
-
+			cleartext, err = c.aerc.Crypto.Encrypt(&buf, rcpts, signerEmail, c.aerc.DecryptKeys, header)
 			if err != nil {
 				return err
 			}
 		} else {
-			cleartext, err = pgpmail.Sign(&buf, header.Header.Header,
-				signer, nil)
+			cleartext, err = c.aerc.Crypto.Sign(&buf, signerEmail, c.aerc.DecryptKeys, header)
 			if err != nil {
 				return err
 			}
@@ -1031,30 +1017,3 @@ func (rm *reviewMessage) OnInvalidate(fn func(ui.Drawable)) {
 func (rm *reviewMessage) Draw(ctx *ui.Context) {
 	rm.grid.Draw(ctx)
 }
-
-func getSigner(c *Composer) (signer *openpgp.Entity, err error) {
-	signerEmail, err := getSenderEmail(c)
-	if err != nil {
-		return nil, err
-	}
-	signer, err = lib.GetSignerEntityByEmail(signerEmail)
-	if err != nil {
-		return nil, err
-	}
-
-	key, ok := signer.SigningKey(time.Now())
-	if !ok {
-		return nil, fmt.Errorf("no signing key found for %s", signerEmail)
-	}
-
-	if !key.PrivateKey.Encrypted {
-		return signer, nil
-	}
-
-	_, err = c.aerc.DecryptKeys([]openpgp.Key{key}, false)
-	if err != nil {
-		return nil, err
-	}
-
-	return signer, nil
-}
diff --git a/widgets/msglist.go b/widgets/msglist.go
index 5eee7ed4..df24526a 100644
--- a/widgets/msglist.go
+++ b/widgets/msglist.go
@@ -295,7 +295,8 @@ func (ml *MessageList) MouseEvent(localX int, localY int, event tcell.Event) {
 				if msg == nil {
 					return
 				}
-				lib.NewMessageStoreView(msg, store, ml.aerc.DecryptKeys,
+				lib.NewMessageStoreView(msg, store, ml.aerc.Crypto,
+					ml.aerc.DecryptKeys,
 					func(view lib.MessageView, err error) {
 						if err != nil {
 							ml.aerc.PushError(err.Error())
diff --git a/widgets/msgviewer.go b/widgets/msgviewer.go
index 89cbc2cc..c88c9817 100644
--- a/widgets/msgviewer.go
+++ b/widgets/msgviewer.go
@@ -75,9 +75,9 @@ func NewMessageViewer(acct *AccountView,
 		{Strategy: ui.SIZE_EXACT, Size: ui.Const(headerHeight)},
 	}
 
-	if msg.PGPDetails() != nil {
+	if msg.MessageDetails() != nil {
 		height := 1
-		if msg.PGPDetails().IsSigned && msg.PGPDetails().IsEncrypted {
+		if msg.MessageDetails().IsSigned && msg.MessageDetails().IsEncrypted {
 			height = 2
 		}
 		rows = append(rows, ui.GridSpec{Strategy: ui.SIZE_EXACT, Size: ui.Const(height)})
@@ -107,8 +107,8 @@ func NewMessageViewer(acct *AccountView,
 	borderChar := acct.UiConfig().BorderCharHorizontal
 
 	grid.AddChild(header).At(0, 0)
-	if msg.PGPDetails() != nil {
-		grid.AddChild(NewPGPInfo(msg.PGPDetails(), acct.UiConfig())).At(1, 0)
+	if msg.MessageDetails() != nil {
+		grid.AddChild(NewPGPInfo(msg.MessageDetails(), acct.UiConfig())).At(1, 0)
 		grid.AddChild(ui.NewFill(borderChar, borderStyle)).At(2, 0)
 		grid.AddChild(switcher).At(3, 0)
 	} else {
diff --git a/widgets/pgpinfo.go b/widgets/pgpinfo.go
index 6c07ed91..8dc05707 100644
--- a/widgets/pgpinfo.go
+++ b/widgets/pgpinfo.go
@@ -1,22 +1,18 @@
 package widgets
 
 import (
-	"errors"
-
 	"git.sr.ht/~rjarry/aerc/config"
 	"git.sr.ht/~rjarry/aerc/lib/ui"
-
-	"github.com/ProtonMail/go-crypto/openpgp"
-	pgperrors "github.com/ProtonMail/go-crypto/openpgp/errors"
+	"git.sr.ht/~rjarry/aerc/models"
 )
 
 type PGPInfo struct {
 	ui.Invalidatable
-	details  *openpgp.MessageDetails
+	details  *models.MessageDetails
 	uiConfig config.UIConfig
 }
 
-func NewPGPInfo(details *openpgp.MessageDetails, uiConfig config.UIConfig) *PGPInfo {
+func NewPGPInfo(details *models.MessageDetails, uiConfig config.UIConfig) *PGPInfo {
 	return &PGPInfo{details: details, uiConfig: uiConfig}
 }
 
@@ -27,38 +23,33 @@ func (p *PGPInfo) DrawSignature(ctx *ui.Context) {
 	defaultStyle := p.uiConfig.GetStyle(config.STYLE_DEFAULT)
 
 	// TODO: Nicer prompt for TOFU, fetch from keyserver, etc
-	if errors.Is(p.details.SignatureError, pgperrors.ErrUnknownIssuer) ||
-		p.details.SignedBy == nil {
+	if p.details.SignatureValidity == models.UnknownEntity ||
+		p.details.SignedBy == "" {
 
 		x := ctx.Printf(0, 0, warningStyle, "*")
 		x += ctx.Printf(x, 0, defaultStyle,
 			" Signed with unknown key (%8X); authenticity unknown",
 			p.details.SignedByKeyId)
-	} else if p.details.SignatureError != nil {
+	} else if p.details.SignatureValidity != models.Valid {
 		x := ctx.Printf(0, 0, errorStyle, "Invalid signature!")
 		x += ctx.Printf(x, 0, errorStyle,
 			" This message may have been tampered with! (%s)",
-			p.details.SignatureError.Error())
+			p.details.SignatureError)
 	} else {
-		entity := p.details.SignedBy.Entity
-		ident := entity.PrimaryIdentity()
-
 		x := ctx.Printf(0, 0, validStyle, "✓ Authentic ")
 		x += ctx.Printf(x, 0, defaultStyle,
 			"Signature from %s (%8X)",
-			ident.Name, p.details.SignedByKeyId)
+			p.details.SignedBy, p.details.SignedByKeyId)
 	}
 }
 
 func (p *PGPInfo) DrawEncryption(ctx *ui.Context, y int) {
 	validStyle := p.uiConfig.GetStyle(config.STYLE_SUCCESS)
 	defaultStyle := p.uiConfig.GetStyle(config.STYLE_DEFAULT)
-	entity := p.details.DecryptedWith.Entity
-	ident := entity.PrimaryIdentity()
 
 	x := ctx.Printf(0, y, validStyle, "✓ Encrypted ")
 	x += ctx.Printf(x, y, defaultStyle,
-		"To %s (%8X) ", ident.Name, p.details.DecryptedWith.PublicKey.KeyId)
+		"To %s (%8X) ", p.details.DecryptedWith, p.details.DecryptedWithKeyId)
 }
 
 func (p *PGPInfo) Draw(ctx *ui.Context) {