Letter frequencies, index of coincidence and the most likely Caesar shift of a c...

{ "method": "GET", "queryParams": { "text": "Wklv lv d vhfuhw phvvdjh derxw d fdhvdu flskhu zlwk d ixqqb vkliw" }, "type": "http" }

{ "example": { "asOf": "2026-10-11T14:31:57.586Z", "candidatePlaintext": "This is a secret message about a caesar cipher with a funny shift", "degraded": false, "disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.", "englishIC": 0.0667, "frequencies": [ { "count": 0, "englishPercent": 8.167, "letter": "A", "percent": 0 }, { "count": 1, "englishPercent": 1.492, "letter": "B", "percent": 1.8868 } ], "indexOfCoincidence": 0.0668, "interpretation": "single-alphabet text (plain English or a Caesar/substitution cipher of it)", "letters": 53, "likelyShift": 3, "mostCommon": [ "D 13.2075%", "V 13.2075%", "…3 more" ], "notChecked": [ "languages other than English (the shift guess assumes English letter frequencies)", "texts under about 40 letters, where statistics are unreliable", "…1 more" ], "randomIC": 0.0385, "reasons": [ "English text has an index of coincidence near 0.066; random letters near 0.038.", "The shift guess minimises the chi-squared distance from English letter frequencies; confidence is the ratio of the runner-up's distance to the best." ], "runnerUpShift": 16, "shiftConfidenceRatio": 8.66, "source": "computed locally (Lewand English letter frequencies, Friedman index of coincidence)", "summary": "IC 0.0668; most likely Caesar shift 3 (decode with shift -3). Most common: D 13.2075%, V 13.2075%, H 11.3208%, L 9.434%, W 9.434%.", "verdict": "LIKELY_CAESAR_SHIFT" }, "type": "json" }