diff --git a/cmd/key_generate.go b/cmd/key_generate.go
index 87e3905..0a8a3a3 100644
--- a/cmd/key_generate.go
+++ b/cmd/key_generate.go
@@ -1,10 +1,13 @@
 package cmd
 
 import (
+	"bytes"
 	stdcrypto "crypto"
 	"errors"
 	"fmt"
+	"os/exec"
 	"os/user"
+	"strconv"
 	"strings"
 	"time"
 
@@ -21,9 +24,14 @@ type KeyGenerate struct {
 	ktype   string
 	comment string
 	bits    int
-	ttl     time.Duration
+	ttl     string
 }
 
+const (
+	day  = 24 * time.Hour
+	year = 8766 * time.Hour // average year is 365.25 days
+)
+
 func (cmd KeyGenerate) Command() *cobra.Command {
 	c := &cobra.Command{
 		Use:     "generate",
@@ -40,17 +48,21 @@ func (cmd KeyGenerate) Command() *cobra.Command {
 	c.Flags().StringVarP(&cmd.comment, "comment", "c", "", "a note to add to the key")
 	c.Flags().StringVarP(&cmd.ktype, "type", "t", "rsa", "type of the key")
 	c.Flags().IntVarP(&cmd.bits, "bits", "b", 4096, "size of RSA key in bits")
-	year := 24 * time.Hour * 365 * 2
-	// TODO: use another duration parser to support days, months, and years
-	c.Flags().DurationVar(&cmd.ttl, "ttl", year, "validity period of the key")
+	c.Flags().StringVar(
+		&cmd.ttl, "ttl", "1y",
+		"validity period of the key. Can be a date (2020-12-30) or duration (4y30d, 24h)",
+	)
 	return c
 }
 
 func (cmd KeyGenerate) run() error {
 	username := cmd.Username()
-	if username == "" {
-		return errors.New("--name is required")
+	email := cmd.Email()
+	ttl, err := ParseDuration(cmd.ttl)
+	if err != nil {
+		return fmt.Errorf("cannot parse --ttl: %v", err)
 	}
+
 	alg := cmd.algorithm()
 	if alg == 0 {
 		return fmt.Errorf("unsupported key type: %v", cmd.ktype)
@@ -61,14 +73,14 @@ func (cmd KeyGenerate) run() error {
 	cfg := &packet.Config{
 		Algorithm:              alg,
 		RSABits:                cmd.bits,
-		KeyLifetimeSecs:        uint32(cmd.ttl.Seconds()),
+		KeyLifetimeSecs:        uint32(ttl.Seconds()),
 		Time:                   crypto.GetTime,
 		DefaultHash:            stdcrypto.SHA256,
 		DefaultCipher:          packet.CipherAES256,
 		DefaultCompressionAlgo: packet.CompressionZLIB,
 	}
 
-	entity, err := openpgp.NewEntity(username, cmd.comment, cmd.email, cfg)
+	entity, err := openpgp.NewEntity(username, cmd.comment, email, cfg)
 	if err != nil {
 		return fmt.Errorf("cannot create entity: %v", err)
 	}
@@ -96,6 +108,20 @@ func (cmd KeyGenerate) Username() string {
 	return ""
 }
 
+func (cmd KeyGenerate) Email() string {
+	if cmd.email != "" {
+		return cmd.email
+	}
+	c := exec.Command("git", "config", "user.email")
+	var stdout bytes.Buffer
+	c.Stdout = &stdout
+	err := c.Run()
+	if err == nil {
+		return strings.TrimSpace(stdout.String())
+	}
+	return ""
+}
+
 func (cmd KeyGenerate) algorithm() packet.PublicKeyAlgorithm {
 	switch strings.ToLower(cmd.ktype) {
 	case "rsa":
@@ -114,3 +140,46 @@ func (cmd KeyGenerate) algorithm() packet.PublicKeyAlgorithm {
 		return 0
 	}
 }
+
+func ParseDuration(ttl string) (time.Duration, error) {
+	if ttl == "" {
+		return 0, nil
+	}
+	t, err := time.Parse("2006-01-02", ttl)
+	if err == nil {
+		return t.Sub(time.Now()), nil
+	}
+
+	var shift time.Duration
+
+	// parse years
+	parts := strings.Split(ttl, "y")
+	if len(parts) == 2 {
+		years, err := strconv.Atoi(parts[0])
+		if err != nil {
+			return 0, fmt.Errorf("parse year: %v", err)
+		}
+		shift += time.Duration(years) * year
+		ttl = parts[1]
+	}
+
+	// parse days
+	parts = strings.Split(ttl, "d")
+	if len(parts) == 2 {
+		days, err := strconv.Atoi(parts[0])
+		if err != nil {
+			return 0, fmt.Errorf("parse year: %v", err)
+		}
+		shift += time.Duration(days) * day
+		ttl = parts[1]
+	}
+
+	if ttl == "" {
+		return shift, nil
+	}
+	d, err := time.ParseDuration(ttl)
+	if err != nil {
+		return 0, err
+	}
+	return d + shift, nil
+}
diff --git a/cmd/key_generate_test.go b/cmd/key_generate_test.go
index a800028..e3965a0 100644
--- a/cmd/key_generate_test.go
+++ b/cmd/key_generate_test.go
@@ -3,7 +3,9 @@ package cmd_test
 import (
 	"bytes"
 	"testing"
+	"time"
 
+	"github.com/life4/enc/cmd"
 	"github.com/matryer/is"
 )
 
@@ -21,3 +23,27 @@ func TestKeyGenerate_IsRandom(t *testing.T) {
 	out2 := CallHappy(t, "key generate", nil)
 	is.True(!bytes.Equal(out1, out2))
 }
+
+func TestParseDuration(t *testing.T) {
+	t.Parallel()
+	testCases := []struct {
+		given    string
+		expected time.Duration
+	}{
+		{"4h", 4 * time.Hour},
+		{"5d", 5 * 24 * time.Hour},
+		{"5d4h", (5*24 + 4) * time.Hour},
+		{"2y", 2 * 8766 * time.Hour},
+		{"4h20m", 4*time.Hour + 20*time.Minute},
+	}
+	for _, tCase := range testCases {
+		tc := tCase
+		t.Run(tc.given, func(t *testing.T) {
+			is := is.New(t)
+			t.Parallel()
+			actual, err := cmd.ParseDuration(tc.given)
+			is.NoErr(err)
+			is.Equal(actual, tc.expected)
+		})
+	}
+}
diff --git a/cmd/key_info.go b/cmd/key_info.go
index eaf025f..f785c2d 100644
--- a/cmd/key_info.go
+++ b/cmd/key_info.go
@@ -42,11 +42,13 @@ func (cmd KeyInfo) run() error {
 		expiration := prim.CreationTime.Add(time.Duration(*ttl) * time.Second)
 		expirationStr = expiration.Format(time.RFC3339)
 	}
+	bits, _ := prim.BitLength()
 	result := map[string]interface{}{
 		// basic key info
 		"id":           key.GetHexKeyID(),
 		"fingerprint":  key.GetFingerprint(),
 		"algorithm":    cmd.algorithm(key),
+		"bits":         bits,
 		"created_at":   prim.CreationTime.Format(time.RFC3339),
 		"expires_at":   expirationStr,
 		"fingerprints": key.GetSHA256Fingerprints(),