Impara
Più regole di codifica vengono applicate in sequenza.
Combined codes apply multiple transformations in sequence. For example, first reverse the alphabet, then shift by 2. Or first convert to numbers, then apply an operation. These are more complex because you must apply each rule in the correct order. The key will usually show the final result.
Apply Rule 1 to get intermediate result, then apply Rule 2 to get final result
- Reverse then shift 1: A→Z→A (reverse gives Z, shift gives A)
- Shift 2 then reverse: A→C→X (shift gives C, reverse gives X)
- Number + 5: A=1+5=6, B=2+5=7, etc.
Come riconoscerlo
- Key doesn't match any single simple pattern
- May need to work backwards to identify rules
- Look for two-step transformations in examples
Errori comuni
- Applying rules in the wrong order
- Trying to find a single rule when two are needed
- Not checking your work by encoding back
Soluzione passo per passo
Codifica 'AB' con: prima spostamento +2, poi inverti alfabeto
- Passo 1: Sposta A di +2 → C
- Passo 2: Inverti C → X (C è 3a, X è 3a dalla fine)
- Passo 1: Sposta B di +2 → D
- Passo 2: Inverti D → W (D è 4a, W è 4a dalla fine)
Risposta: XW