Atbash & レールフェンス暗号とは？

無料のオンライン Atbash 暗号とレールフェンス暗号ツール。古典的な暗号アルゴリズムを使用してテキストを暗号化または復号。

The Atbash cipher is one of the oldest known encryption methods, dating back to ancient Hebrew texts where it was used to conceal meaning. It works by reversing the alphabet: A becomes Z, B becomes Y, C becomes X, and so on. The Rail Fence cipher, by contrast, is a transposition cipher that rearranges letters by writing them diagonally across rows (rails) and reading them row by row.

Atbash is a monoalphabetic substitution with the unique property of being self-inverse — applying it twice returns the original text. This makes it simple to use: switch between encrypt and decrypt as needed. An optional digit reversal mode maps 0↔9, 1↔8, 2↔7, and so on, extending the cipher's reach to numeric content.

The Rail Fence cipher writes text across a configurable number of rails (2 to 10). For example, with 3 rails, the text "HELLO WORLD" is written diagonally across three rows, creating a zigzag pattern. The encrypted text is formed by reading row by row. The rail pattern visualization shows exactly how each letter is placed on each rail, making the transposition clear.

Both ciphers are intended for learning, puzzles, and historical interest. Neither provides any real security against modern cryptanalysis. The Rail Fence cipher can be cracked by trying different rail counts (only 2-10 possibilities) and looking for readable output.