func Test3(t *testing.T) {
// Decode ciphertext
ciphertext, err := encoding.DecodeHex([]byte(input3))
if err != nil {
t.Error("Decoding", input3, "failed")
}
// Attempt to find byte most likely xor'd with ciphertext
closestByte := xorbyte.FindByte(ciphertext, xorbyte.EnglishScorer)
// Construct key from most likely byte
key := make([]byte, len(ciphertext))
for i := 0; i < len(key); i++ {
key[i] = closestByte
}
// Decrypt ciphertext
plaintext, _ := bits.Xor(ciphertext, key)
// output plaintext
if string(plaintext) != output3 {
t.Error("Incorrect key chosen:", string(closestByte), string(plaintext))
}
}
func FindKey(ciphertext []byte) ([]byte, error) {
keysize, err := FindKeysize(ciphertext, KEYSIZE_LOW, KEYSIZE_HIGH, SAMPLE_BLOCKS)
if err != nil {
return nil, err
}
fmt.Println(keysize)
// TODO: How does padding affect single xor cracking?
transposed, err := bits.Transpose(ciphertext, keysize)
if err != nil {
return nil, err
}
blocksTotal := len(transposed) / keysize
key := make([]byte, blocksTotal)
for i := 0; i < blocksTotal; i++ {
block := transposed[i*keysize : (i+1)*keysize]
key[i] = xorbyte.FindByte(block, xorbyte.EnglishScorer)
}
return key, nil
}