diff --git a/pkg/manifestgen/sourcesecret/sourcesecret.go b/pkg/manifestgen/sourcesecret/sourcesecret.go
index e5ce4f21..19342319 100644
--- a/pkg/manifestgen/sourcesecret/sourcesecret.go
+++ b/pkg/manifestgen/sourcesecret/sourcesecret.go
@@ -18,7 +18,6 @@ package sourcesecret
 
 import (
 	"bytes"
-	"encoding/pem"
 	"fmt"
 	"io/ioutil"
 	"net"
@@ -131,12 +130,7 @@ func loadKeyPair(path string) (*ssh.KeyPair, error) {
 		return nil, fmt.Errorf("failed to open private key file: %w", err)
 	}
 
-	block, _ := pem.Decode(b)
-	if block == nil {
-		return nil, fmt.Errorf("failed to decode PEM block")
-	}
-
-	ppk, err := cryptssh.ParsePrivateKey(block.Bytes)
+	ppk, err := cryptssh.ParsePrivateKey(b)
 	if err != nil {
 		return nil, err
 	}
diff --git a/pkg/manifestgen/sourcesecret/sourcesecret_test.go b/pkg/manifestgen/sourcesecret/sourcesecret_test.go
new file mode 100644
index 00000000..89402425
--- /dev/null
+++ b/pkg/manifestgen/sourcesecret/sourcesecret_test.go
@@ -0,0 +1,40 @@
+/*
+Copyright 2021 The Flux authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package sourcesecret
+
+import (
+	"io/ioutil"
+	"reflect"
+	"testing"
+)
+
+func Test_loadKeyPair(t *testing.T) {
+	pk, _ := ioutil.ReadFile("testdata/rsa")
+	ppk, _ := ioutil.ReadFile("testdata/rsa.pub")
+
+	got, err := loadKeyPair("testdata/rsa")
+	if err != nil {
+		t.Errorf("loadKeyPair() error = %v", err)
+		return
+	}
+	if !reflect.DeepEqual(got.PrivateKey, pk) {
+		t.Errorf("PrivateKey %s != %s", got.PrivateKey, pk)
+	}
+	if !reflect.DeepEqual(got.PublicKey, ppk) {
+		t.Errorf("PublicKey %s != %s", got.PublicKey, ppk)
+	}
+}
diff --git a/pkg/manifestgen/sourcesecret/testdata/rsa b/pkg/manifestgen/sourcesecret/testdata/rsa
new file mode 100644
index 00000000..da914d80
--- /dev/null
+++ b/pkg/manifestgen/sourcesecret/testdata/rsa
@@ -0,0 +1,38 @@
+-----BEGIN OPENSSH PRIVATE KEY-----
+b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAABlwAAAAdzc2gtcn
+NhAAAAAwEAAQAAAYEA3igXbgoTAydPOiEb4VfRPM4e26S16ZXhIEt95vka8wdcru97JKFl
+3yK6i0RALylrMAyjequXTNntZm2unngMuYE3OeFoY3dE1/xcWEVu8gE6AiGv74SzQsKtQv
+lqlXhF9s2cVyfJLmt5cvQP6zRxmx8KaZL6bN3PLDMIuq4Lit3BEn9KON89+uWKjXr9jU6/
+MlaQ4jn9VYMczhMDQpTyTMFgIBLuJYa4RUQ9vpL/KvgzpXh/bSf0B7DvEt+It2Qiws+RXH
+sc/cdxEDNRVwBOeueqSFZjw83fg5p3G5mMKUG0MLiNk0gw3S7JZKRndKiyKQZ7UCpfiRsk
+YJLZGGP8BeUGC5nYLicZAYJLddHyoq8jp8AtlGcKxgAQfWTjjlI2ppJPYpM2yncgnpv8Rk
+QiDH9onIjTxx715IDiLmsjesFi8weQrPXQ/OkBY0qud4A/piHiSg2/mcQ4bD+yNXP7ka7n
+hiGI/NPPSb/Q+a9SXa72VMI3z6s4/MKXL47t1NaNAAAFiMj8bezI/G3sAAAAB3NzaC1yc2
+EAAAGBAN4oF24KEwMnTzohG+FX0TzOHtuktemV4SBLfeb5GvMHXK7veyShZd8iuotEQC8p
+azAMo3qrl0zZ7WZtrp54DLmBNznhaGN3RNf8XFhFbvIBOgIhr++Es0LCrUL5apV4RfbNnF
+cnyS5reXL0D+s0cZsfCmmS+mzdzywzCLquC4rdwRJ/SjjfPfrlio16/Y1OvzJWkOI5/VWD
+HM4TA0KU8kzBYCAS7iWGuEVEPb6S/yr4M6V4f20n9Aew7xLfiLdkIsLPkVx7HP3HcRAzUV
+cATnrnqkhWY8PN34OadxuZjClBtDC4jZNIMN0uyWSkZ3SosikGe1AqX4kbJGCS2Rhj/AXl
+BguZ2C4nGQGCS3XR8qKvI6fALZRnCsYAEH1k445SNqaST2KTNsp3IJ6b/EZEIgx/aJyI08
+ce9eSA4i5rI3rBYvMHkKz10PzpAWNKrneAP6Yh4koNv5nEOGw/sjVz+5Gu54YhiPzTz0m/
+0PmvUl2u9lTCN8+rOPzCly+O7dTWjQAAAAMBAAEAAAGBAKv82868C+YIG8UD9uKpKvrpFG
+i1BoR1HVn0N9+GAQAfNfjUvEAql4R9DXBeAVbBuRL05edFSpgbqzf+OA7FIAzJZajwwfEn
+V+vimtdXwcGng3I9BEjpMiLANoTANWzMNVYR7jRnP9ApMlf1bRGJg141VMlRGYEI46fzRp
+HHxnXWoe+hDiQjaIeCB5bqnbs1OL5O2FHb1S3LmJRNkduNFlyn5LRQE4CH4Mb3Qtn0UYnB
+p7I2LGikYr9FkoDI/74CzZkL8OK01pfgSNbVrmJ3afFra7LrMYNUqseKsWIPvwCnHjr2hL
+LRxW6DU6CYZjy02ZBpkmISCBFSaLNbh0rH47B842lqrFPrEdGKBvlHJLHqzKDCBW+PSaHD
+K30kclgO1laxx0zdTUipYPPuJLL+2iHYWMYtKdDkpS96+BjoKKen0uZUhGamk2/rCbY1Gi
+p/iWjNlDKExWjpnQd4KfyQvrds2KGj1+4loFLxT6akmi57aCj7rqKbiBfbaPuVUMp6HQAA
+AMEA8Jx79pkkCIhnA8DabHp3RBfRyaJvomka2O6XaiCdzs03U/9h8I6ROwJZ4bXXOar6n9
+KrPXC4gRIBuqxoFaBcTHNIwH5apzeptJrAXe4baKJIGjG9KWP5brbyGzOsqj0Lx1bFiiro
+eDMOQCUFjpQ5DkwQTqpInzWLvt5bixMxQutqw4iirgB065j39UzgjPbFwI1+S/vTU2S68k
+qicpRmlz/hHjZX+wEPAwaUa9nBPPWv7tOqg0CYMFDwQbuT9WkuAAAAwQD28BUPrDCD4Sl+
+EI5kE6eyk9tdpTlMtgiLbH2WJO9yr4C/GVmQytujb6YXHAtZ3IXf8Wg6sXY8JH36dGTqZP
+gJaZfzhC4SEJvCUXWim/rdxj4CQMZW7o7guMME3w5hDHitj0vyGxatp30ltwUF6/gpSiEG
+SAI1lSNkZk3Ey0OMZv5Tp0Y5HJ3SBlnystYzzDvlDq4m+cNCmH0IytZV8Udwjkd7knLQce
+gvO+vKTWf6l8nb3BlBYBV72tyKGfd9pSMAAADBAOZPMjJZtQ5yzoklmyxqUiSZl/+aB41H
+IHU89ejt7cynuzIvOi3HWJB4201Z0yaS19xX48httEyxk0MTb5oK1H6yYKAx7m9DVMCq2e
+AJRM42Hh1Eer5bh/wUqdbqrV6NWkiXP7s440ml8tAsVULCKqQPRyPo1UBkayudMBx3Ke0W
+2sKWZDMT7OzC3lR4QdyC8keLzJhfudnP5ZWstOWgkTkPoZZ6EZZBz2gMVMEVczGcMYLIub
+eulFT3H8VUH5mIjwAAAAtoaWRkZUByaWRlcgECAwQFBg==
+-----END OPENSSH PRIVATE KEY-----
diff --git a/pkg/manifestgen/sourcesecret/testdata/rsa.pub b/pkg/manifestgen/sourcesecret/testdata/rsa.pub
new file mode 100644
index 00000000..fe44a0f3
--- /dev/null
+++ b/pkg/manifestgen/sourcesecret/testdata/rsa.pub
@@ -0,0 +1 @@
+ssh-rsa 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