func TestPKCS7Padding(t *testing.T) {
// Verify the PKCS7 padding, using a human readable plaintext.
// 0 byte/length message
msg := []byte("")
expected := []byte{16, 16, 16, 16,
16, 16, 16, 16,
16, 16, 16, 16,
16, 16, 16, 16}
result := primitives.PKCS7Padding(msg)
if !bytes.Equal(expected, result) {
t.Fatal("Padding error! Expected: ", expected, "', received: '", result, "'")
}
// 1 byte/length message
msg = []byte("0")
expected = []byte{'0', 15, 15, 15,
15, 15, 15, 15,
15, 15, 15, 15,
15, 15, 15, 15}
result = primitives.PKCS7Padding(msg)
if !bytes.Equal(expected, result) {
t.Fatal("Padding error! Expected: '", expected, "', received: '", result, "'")
}
// 2 byte/length message
msg = []byte("01")
expected = []byte{'0', '1', 14, 14,
14, 14, 14, 14,
14, 14, 14, 14,
14, 14, 14, 14}
result = primitives.PKCS7Padding(msg)
if !bytes.Equal(expected, result) {
t.Fatal("Padding error! Expected: '", expected, "', received: '", result, "'")
}
// 3 to aes.BlockSize-1 byte messages
for i := 3; i < aes.BlockSize; i++ {
msg := []byte("0123456789ABCDEF")
result := primitives.PKCS7Padding(msg[:i])
padding := aes.BlockSize - i
expectedPadding := bytes.Repeat([]byte{byte(padding)}, padding)
expected = append(msg[:i], expectedPadding...)
if !bytes.Equal(result, expected) {
t.Fatal("Padding error! Expected: '", expected, "', received: '", result, "'")
}
}
// aes.BlockSize length message
msg = bytes.Repeat([]byte{byte('x')}, aes.BlockSize)
result = primitives.PKCS7Padding(msg)
expectedPadding := bytes.Repeat([]byte{byte(aes.BlockSize)},
aes.BlockSize)
expected = append(msg, expectedPadding...)
if len(result) != 2*aes.BlockSize {
t.Fatal("Padding error: expected the length of the returned slice to be 2 times aes.BlockSize")
}
if !bytes.Equal(expected, result) {
t.Fatal("Padding error! Expected: '", expected, "', received: '", result, "'")
}
}
// TestPKCS7Padding verifies the PKCS#7 padding, using a human readable plaintext.
func TestPKCS7Padding(t *testing.T) {
// 0 byte/length ptext
ptext := []byte("")
expected := []byte{16, 16, 16, 16,
16, 16, 16, 16,
16, 16, 16, 16,
16, 16, 16, 16}
result := primitives.PKCS7Padding(ptext)
if !bytes.Equal(expected, result) {
t.Fatal("Padding error! Expected: ", expected, "', received: '", result, "'")
}
// 1 byte/length ptext
ptext = []byte("1")
expected = []byte{'1', 15, 15, 15,
15, 15, 15, 15,
15, 15, 15, 15,
15, 15, 15, 15}
result = primitives.PKCS7Padding(ptext)
if !bytes.Equal(expected, result) {
t.Fatal("Padding error! Expected: '", expected, "', received: '", result, "'")
}
// 2 byte/length ptext
ptext = []byte("12")
expected = []byte{'1', '2', 14, 14,
14, 14, 14, 14,
14, 14, 14, 14,
14, 14, 14, 14}
result = primitives.PKCS7Padding(ptext)
if !bytes.Equal(expected, result) {
t.Fatal("Padding error! Expected: '", expected, "', received: '", result, "'")
}
// 3 to aes.BlockSize-1 byte plaintext
ptext = []byte("1234567890ABCDEF")
for i := 3; i < aes.BlockSize; i++ {
result := primitives.PKCS7Padding(ptext[:i])
padding := aes.BlockSize - i
expectedPadding := bytes.Repeat([]byte{byte(padding)}, padding)
expected = append(ptext[:i], expectedPadding...)
if !bytes.Equal(result, expected) {
t.Fatal("Padding error! Expected: '", expected, "', received: '", result, "'")
}
}
// aes.BlockSize length ptext
ptext = bytes.Repeat([]byte{byte('x')}, aes.BlockSize)
result = primitives.PKCS7Padding(ptext)
expectedPadding := bytes.Repeat([]byte{byte(aes.BlockSize)}, aes.BlockSize)
expected = append(ptext, expectedPadding...)
if len(result) != 2*aes.BlockSize {
t.Fatal("Padding error: expected the length of the returned slice to be 2 times aes.BlockSize")
}
if !bytes.Equal(expected, result) {
t.Fatal("Padding error! Expected: '", expected, "', received: '", result, "'")
}
}