What is Echo and how do you use this function?

The echo cipher is a secret code in which letters are changed by looking at where a beam of light ends up after bouncing against the inside of a round tube.

On the outside of the tube are symbols, such as letters or numbers. Each symbol has a small hole where light can enter.
The tube has at least as many sides as the number of symbols in the list.

What is the Echo cipher?

In this example, the text GC WIZARD becomes the code GAGCGC WC. The light beam bounces along the characters in this order: G R W C Z I D A.
This sequence determines how the light moves inside the tube.

To encode a message, the first symbol is the starting point. A beam of light is shone through the hole at this symbol. The beam is aimed so that it hits the mirror inside at the position of the next symbol in the message. Because light always reflects in the same way, the beam leaves the tube through another hole. The symbol at this exit hole becomes the new secret symbol.
This is repeated for the rest of the symbols until the entire message has been converted.
The first letter of the text never changes. It stays the same so the receiver knows where the light beam must start in order to decode the message.

The Echo function in GC Wizard

In GC Wizard, this function can be found under: Encryption and Codes / Echo

How does the function work?

At the top of the screen there are two text fields.

Text field: The original or encoded text

In the first text field you enter the text you want to Encrypt or Decrypt.

Text field: The key

In the second text field you enter the key.
These are the characters that must appear on the cylinder.

The key must meet several conditions:

  • The characters used in the text must also appear in the key.
    If characters are missing, the following error message appears:
    Unknown character: All characters must be found in the key.
  • The key must contain an odd number of characters.
    If the key has an even number of characters, the following error message appears:
    Key must have an odd number of characters.

Slider: Mode

With the slider Mode you choose whether the text should be encoded (Encode) or decoded (Decode).

Output

Under Output the encoded or decoded text appears.
Next to this text is a copy button that copies the result to the clipboard.