57 lines
1.5 KiB
Go
57 lines
1.5 KiB
Go
package winpwn
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import (
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"bytes"
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"testing"
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)
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func TestFindXORKeyAvoidsBadChars(t *testing.T) {
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data := []byte{0x00, 0x0A, 0x0D, 0x41, 0x42}
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badChars := []byte{0x00, 0x0A, 0x0D}
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key, err := FindXORKey(data, badChars)
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if err != nil {
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t.Fatal(err)
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}
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encoded := Xor(data, []byte{key})
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if HasBadChars(encoded, badChars) {
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t.Errorf("encoded output %x still contains a bad char (key=0x%02x)", encoded, key)
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}
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}
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func TestEncodeXORRoundTrip(t *testing.T) {
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data := []byte("the quick brown fox")
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badChars := []byte{0x00, 0x0A, 0x0D, 0x20} // also avoid spaces, for fun
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encoded, key, err := EncodeXOR(data, badChars)
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if err != nil {
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t.Fatal(err)
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}
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if HasBadChars(encoded, badChars) {
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t.Errorf("encoded output still has bad chars")
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}
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decoded := Xor(encoded, []byte{key})
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if !bytes.Equal(decoded, data) {
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t.Errorf("decoded = %q, want %q", decoded, data)
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}
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}
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func TestFindXORKeyImpossible(t *testing.T) {
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// Every byte 0..255 appears in data, so no key can avoid every byte
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// being a bad char if badChars also covers every value the key could
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// produce -- construct a case that's provably impossible: data
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// contains every byte value, and badChars also contains every byte
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// value, so any key XORed against some data byte lands on a bad byte.
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data := make([]byte, 256)
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for i := range data {
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data[i] = byte(i)
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}
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badChars := data // all 256 values are "bad"
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if _, err := FindXORKey(data, badChars); err == nil {
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t.Error("expected an error when every byte value is both present and forbidden")
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}
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}
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