Leren
Elke letter wordt een vast aantal posities in het alfabet verschoven.
The Caesar cipher shifts each letter by a fixed number of positions. If the shift is 3, A becomes D, B becomes E, and so on. At the end of the alphabet, it wraps around: X→A, Y→B, Z→C (with shift 3). Named after Julius Caesar who reportedly used a shift of 3 for military messages.
Shifted letter = (Original position + Shift) mod 26. With shift=3: A→D, B→E, C→F, ..., X→A, Y→B, Z→C
- Shift 1: CAT → DBU
- Shift 3: HELLO → KHOOR
- Shift 5: APPLE → FUUQJ
Zo herkent u het
- All letters shifted by the same amount
- Key shows consistent pattern (A→D, B→E means shift 3)
- Wraps around at Z back to A
Veelgemaakte fouten
- Forgetting to wrap around (Y+3 should be B, not beyond Z)
- Shifting in the wrong direction for decoding
- Not identifying the shift value from given examples
Stapsgewijze uitwerking
Codeer 'HELLO' met Caesarcijfer verschuiving 3
- H is de 8e letter. Tel 3 op: positie 11 = K
- E is de 5e letter. Tel 3 op: positie 8 = H
- L is de 12e letter. Tel 3 op: positie 15 = O
- L opnieuw: positie 15 = O
- O is de 15e letter. Tel 3 op: positie 18 = R
Antwoord: KHOOR