giles
60e3ce1c96
Some checks failed
Test, Build, and Deploy / test-build-deploy (push) Failing after 22s
For each character, XOR with the corresponding key char (key cycled
via 'i mod kn'):
let xor_cipher key text =
let buf = Buffer.create n in
for i = 0 to n - 1 do
let c = Char.code text.[i] in
let k = Char.code key.[i mod kn] in
Buffer.add_string buf (String.make 1 (Char.chr (c lxor k)))
done;
Buffer.contents buf
XOR is its own inverse, so encrypt + decrypt with the same key yields
the original. Test combines:
- String.length decoded = 6
- decoded = 'Hello!' -> 1
- 6 * 100 + 1 = 601
Tests Char.code + Char.chr round-trip, the iter-127 lxor operator,
Buffer.add_string + String.make 1, and key-cycling via mod.
90 baseline programs total.
17 lines
471 B
OCaml
17 lines
471 B
OCaml
let xor_cipher key text =
|
|
let n = String.length text in
|
|
let kn = String.length key in
|
|
let buf = Buffer.create n in
|
|
for i = 0 to n - 1 do
|
|
let c = Char.code text.[i] in
|
|
let k = Char.code key.[i mod kn] in
|
|
Buffer.add_string buf (String.make 1 (Char.chr (c lxor k)))
|
|
done;
|
|
Buffer.contents buf
|
|
|
|
;;
|
|
|
|
let encoded = xor_cipher "key" "Hello!" in
|
|
let decoded = xor_cipher "key" encoded in
|
|
String.length decoded * 100 + (if decoded = "Hello!" then 1 else 0)
|