func TestPKCS7UnPadding(t *testing.T) {
// Verify the PKCS7 unpadding, using a human readable plaintext.
// 0 byte/length message
expected := []byte("")
msg := []byte{16, 16, 16, 16,
16, 16, 16, 16,
16, 16, 16, 16,
16, 16, 16, 16}
result, _ := primitives.PKCS7UnPadding(msg)
if !bytes.Equal(expected, result) {
t.Fatal("UnPadding error! Expected: '", expected, "', received: '", result, "'")
}
// 1 byte/length message
expected = []byte("0")
msg = []byte{'0', 15, 15, 15,
15, 15, 15, 15,
15, 15, 15, 15,
15, 15, 15, 15}
result, _ = primitives.PKCS7UnPadding(msg)
if !bytes.Equal(expected, result) {
t.Fatal("UnPadding error! Expected: '", expected, "', received: '", result, "'")
}
// 2 byte/length message
expected = []byte("01")
msg = []byte{'0', '1', 14, 14,
14, 14, 14, 14,
14, 14, 14, 14,
14, 14, 14, 14}
result, _ = primitives.PKCS7UnPadding(msg)
if !bytes.Equal(expected, result) {
t.Fatal("UnPadding error! Expected: '", expected, "', received: '", result, "'")
}
// 3 to aes.BlockSize-1 byte messages
for i := 3; i < aes.BlockSize; i++ {
base := []byte("0123456789ABCDEF")
iPad := aes.BlockSize - i
padding := bytes.Repeat([]byte{byte(iPad)}, iPad)
msg = append(base[:i], padding...)
expected := base[:i]
result, _ := primitives.PKCS7UnPadding(msg)
if !bytes.Equal(result, expected) {
t.Fatal("UnPadding error! Expected: '", expected, "', received: '", result, "'")
}
}
// aes.BlockSize length message
expected = bytes.Repeat([]byte{byte('x')}, aes.BlockSize)
padding := bytes.Repeat([]byte{byte(aes.BlockSize)},
aes.BlockSize)
msg = append(expected, padding...)
result, _ = primitives.PKCS7UnPadding(msg)
if !bytes.Equal(expected, result) {
t.Fatal("UnPadding error! Expected: '", expected, "', received: '", result, "'")
}
}
// TestPKCS7UnPadding verifies the PKCS#7 unpadding, using a human readable plaintext.
func TestPKCS7UnPadding(t *testing.T) {
// 0 byte/length ptext
expected := []byte("")
ptext := []byte{16, 16, 16, 16,
16, 16, 16, 16,
16, 16, 16, 16,
16, 16, 16, 16}
result, _ := primitives.PKCS7UnPadding(ptext)
if !bytes.Equal(expected, result) {
t.Fatal("UnPadding error! Expected: '", expected, "', received: '", result, "'")
}
// 1 byte/length ptext
expected = []byte("1")
ptext = []byte{'1', 15, 15, 15,
15, 15, 15, 15,
15, 15, 15, 15,
15, 15, 15, 15}
result, _ = primitives.PKCS7UnPadding(ptext)
if !bytes.Equal(expected, result) {
t.Fatal("UnPadding error! Expected: '", expected, "', received: '", result, "'")
}
// 2 byte/length ptext
expected = []byte("12")
ptext = []byte{'1', '2', 14, 14,
14, 14, 14, 14,
14, 14, 14, 14,
14, 14, 14, 14}
result, _ = primitives.PKCS7UnPadding(ptext)
if !bytes.Equal(expected, result) {
t.Fatal("UnPadding error! Expected: '", expected, "', received: '", result, "'")
}
// 3 to aes.BlockSize-1 byte plaintext
base := []byte("1234567890ABCDEF")
for i := 3; i < aes.BlockSize; i++ {
iPad := aes.BlockSize - i
padding := bytes.Repeat([]byte{byte(iPad)}, iPad)
ptext = append(base[:i], padding...)
expected := base[:i]
result, _ := primitives.PKCS7UnPadding(ptext)
if !bytes.Equal(result, expected) {
t.Fatal("UnPadding error! Expected: '", expected, "', received: '", result, "'")
}
}
// aes.BlockSize length ptext
expected = bytes.Repeat([]byte{byte('x')}, aes.BlockSize)
padding := bytes.Repeat([]byte{byte(aes.BlockSize)}, aes.BlockSize)
ptext = append(expected, padding...)
result, _ = primitives.PKCS7UnPadding(ptext)
if !bytes.Equal(expected, result) {
t.Fatal("UnPadding error! Expected: '", expected, "', received: '", result, "'")
}
}