Equidistant Letter Sequences (ELS) are sequences of letters found in a text where the letters are separated by a fixed number of other characters. To form an ELS, you typically pick a starting letter and then repeatedly skip a constant number of characters to find the next letter in the sequence. The "interval" or "step size" refers to the total number of positions moved from one selected letter to the next (e.g., an interval of 3 means you select a letter, skip 2, select the next).
For example, in the text "ABCDEFGHIJ", if you start at 'A' (index 0) and use an interval of 3, you would select:
The ELS would be "ADGJ". This technique is famously associated with "Bible codes," where researchers search for such patterns in religious texts, often after arranging the text into a grid or matrix.
ELS can serve as a simple method for message authentication. If a sender and receiver pre-agree on a specific base text, a starting position for the ELS, and an interval, a known hidden keyword extracted using this ELS can act as a "signature." If the main message content is altered, the ELS-derived keyword will likely be disrupted or change entirely. This change would signal potential tampering or indicate that the message is not authentic, as the expected "coded" signature is no longer present or correct.
Using Interval: N/A
Extracted Text (from 1st char, non-letters removed, lowercase):
Note: This tool extracts letters starting from the first character of the processed text (non-alphabetic characters removed, converted to lowercase). The example "This is a test" with interval 2 yielding "hstat" (as mentioned in some ELS discussions) is not produced by this tool's standard ELS extraction from the first character; this tool would yield "tisats". "hstat" would require a different starting point or a non-standard interpretation of ELS.
A specific hidden word, "", is embedded in the text below. The hidden word starts from the first character of the challenge text (after processing it to remove non-letters and convert to lowercase). Can you guess the correct interval used to hide it?
Challenge Text (will be processed to lowercase, non-letters removed):
Your attempt extracts: