diff --git a/openpgp/clearsign/clearsign.go b/openpgp/clearsign/clearsign.go
index c2aac09..6454d22 100644
--- a/openpgp/clearsign/clearsign.go
+++ b/openpgp/clearsign/clearsign.go
@@ -35,7 +35,7 @@ type Block struct {
 // start is the marker which denotes the beginning of a clearsigned message.
 var start = []byte("\n-----BEGIN PGP SIGNED MESSAGE-----")
 
-// dashEscape is prefixed to any lines that begin with a hypen so that they
+// dashEscape is prefixed to any lines that begin with a hyphen so that they
 // can't be confused with endText.
 var dashEscape = []byte("- ")
 
@@ -197,7 +197,17 @@ func (d *dashEscaper) Write(data []byte) (n int, err error) {
 				d.h.Write(crlf)
 			}
 			d.isFirstLine = false
+		}
 
+		// Any whitespace at the end of the line has to be removed so we
+		// buffer it until we find out whether there's more on this line.
+		if b == ' ' || b == '\t' || b == '\r' {
+			d.whitespace = append(d.whitespace, b)
+			d.atBeginningOfLine = false
+			continue
+		}
+
+		if d.atBeginningOfLine {
 			// At the beginning of a line, hyphens have to be escaped.
 			if b == '-' {
 				// The signature isn't calculated over the dash-escaped text so
@@ -208,7 +218,7 @@ func (d *dashEscaper) Write(data []byte) (n int, err error) {
 				d.h.Write(d.byteBuf)
 				d.atBeginningOfLine = false
 			} else if b == '\n' {
-				// Nothing to do because we dely writing CRLF to the hash.
+				// Nothing to do because we delay writing CRLF to the hash.
 			} else {
 				d.h.Write(d.byteBuf)
 				d.atBeginningOfLine = false
@@ -217,15 +227,11 @@ func (d *dashEscaper) Write(data []byte) (n int, err error) {
 				return
 			}
 		} else {
-			// Any whitespace at the end of the line has to be removed so we
-			// buffer it until we find out whether there's more on this line.
-			if b == ' ' || b == '\t' || b == '\r' {
-				d.whitespace = append(d.whitespace, b)
-			} else if b == '\n' {
+			if b == '\n' {
 				// We got a raw \n. Drop any trailing whitespace and write a
 				// CRLF.
 				d.whitespace = d.whitespace[:0]
-				// We dely writing CRLF to the hash until the start of the
+				// We delay writing CRLF to the hash until the start of the
 				// next line.
 				if err = d.buffered.WriteByte(b); err != nil {
 					return
diff --git a/openpgp/clearsign/clearsign_test.go b/openpgp/clearsign/clearsign_test.go
index 51538b9..406377c 100644
--- a/openpgp/clearsign/clearsign_test.go
+++ b/openpgp/clearsign/clearsign_test.go
@@ -64,6 +64,16 @@ var signingTests = []struct {
 	{"a\n", "a", "a\n"},
 	{"-a\n", "-a", "-a\n"},
 	{"--a\nb", "--a\r\nb", "--a\nb\n"},
+	// leading whitespace
+	{" a\n", " a", " a\n"},
+	{"  a\n", "  a", "  a\n"},
+	// trailing whitespace (should be stripped)
+	{"a \n", "a", "a\n"},
+	{"a ", "a", "a\n"},
+	// whitespace-only lines (should be stripped)
+	{"  \n", "", "\n"},
+	{"  ", "", "\n"},
+	{"a\n  \n  \nb\n", "a\r\n\r\n\r\nb", "a\n\n\nb\n"},
 }
 
 func TestSigning(t *testing.T) {