{
  "cipher": "polybius-square",
  "kind": "keyless-cipher",
  "description": "Polybius square coordinates: row then column on the traditional 5x5 grid.",
  "standard": "The 5x5 grid holding 25 letters, with I and J sharing one cell.",
  "notes": "Because I and J share a cell, decoding is lossy and always returns I. Tap code uses this same grid.",
  "map": {
    "a": "11",
    "b": "12",
    "c": "13",
    "d": "14",
    "e": "15",
    "f": "21",
    "g": "22",
    "h": "23",
    "i": "24",
    "k": "25",
    "l": "31",
    "m": "32",
    "n": "33",
    "o": "34",
    "p": "35",
    "q": "41",
    "r": "42",
    "s": "43",
    "t": "44",
    "u": "45",
    "v": "51",
    "w": "52",
    "x": "53",
    "y": "54",
    "z": "55"
  },
  "license": {
    "name": "CC BY 4.0",
    "url": "https://creativecommons.org/licenses/by/4.0/",
    "attribution": "CipherPad (https://cipherpad.dev)"
  },
  "lastUpdated": "2026-07-26",
  "docs": "https://cipherpad.dev/api",
  "tool": "https://cipherpad.dev/translate/polybius-square",
  "reverse": {
    "11": "a",
    "12": "b",
    "13": "c",
    "14": "d",
    "15": "e",
    "21": "f",
    "22": "g",
    "23": "h",
    "24": "i",
    "25": "k",
    "31": "l",
    "32": "m",
    "33": "n",
    "34": "o",
    "35": "p",
    "41": "q",
    "42": "r",
    "43": "s",
    "44": "t",
    "45": "u",
    "51": "v",
    "52": "w",
    "53": "x",
    "54": "y",
    "55": "z"
  }
}