FormatFlow

Cipher Identifier: Heuristic Mystery Text & Cipher Analyzer

Analyze ciphertext using character set heuristics, length tests, and Index of Coincidence to suggest probable ciphers with confidence scores.

Cipher Heuristic AnalysisLength: 16 | Index of Coincidence (IC): 0.1212
Base64 / Base64URLHigh Confidence

Contains valid Base64 character set (A-Z, a-z, 0-9, +, /, =).

* Note: Cipher identification relies on statistical heuristics and is not guaranteed.

Ranked Decoded Candidates (27 algorithms tested)

Caesar (Shift 14)Top Match
Readability Score: 61/100
GUJgpU8ur29mpUE=
Caesar (Shift 24)
Readability Score: 61/100
QETqzE8eb29wzEO=
Caesar (Shift 20)
Readability Score: 60/100
MAPmvA8ax29svAK=
Base64
Readability Score: 57/100
Hello world
Caesar (Shift 8)
Readability Score: 52/100
AODajO8ol29gjOY=
ROT13
Readability Score: 51/100
FTIfoT8tq29loTD=
Caesar (Shift 16)
Readability Score: 51/100
IWLirW8wt29orWG=
Caesar (Shift 19)
Readability Score: 51/100
LZOluZ8zw29ruZJ=
Caesar (Shift 22)
Readability Score: 51/100
OCRoxC8cz29uxCM=
Caesar (Shift 25)
Readability Score: 51/100
RFUraF8fc29xaFP=
Caesar (Shift 2)
Readability Score: 44/100
UIXudI8if29adIS=
Caesar (Shift 3)
Readability Score: 43/100
VJYveJ8jg29beJT=
Caesar (Shift 5)
Readability Score: 43/100
XLAxgL8li29dgLV=
Caesar (Shift 7)
Readability Score: 43/100
ZNCziN8nk29fiNX=
Caesar (Shift 10)
Readability Score: 43/100
CQFclQ8qn29ilQA=
Caesar (Shift 12)
Readability Score: 43/100
ESHenS8sp29knSC=
Caesar (Shift 1)
Readability Score: 34/100
THWtcH8he29zcHR=
Caesar (Shift 4)
Readability Score: 34/100
WKZwfK8kh29cfKU=
Caesar (Shift 6)
Readability Score: 34/100
YMByhM8mj29ehMW=
Caesar (Shift 9)
Readability Score: 34/100
BPEbkP8pm29hkPZ=
Caesar (Shift 11)
Readability Score: 34/100
DRGdmR8ro29jmRB=
Caesar (Shift 17)
Readability Score: 34/100
JXMjsX8xu29psXH=
Caesar (Shift 18)
Readability Score: 34/100
KYNktY8yv29qtYI=
Caesar (Shift 23)
Readability Score: 34/100
PDSpyD8da29vyDN=
Atbash
Readability Score: 34/100
HTEhyT8tw29byTJ=
Caesar (Shift 15)
Readability Score: 30/100
HVKhqV8vs29nqVF=
Caesar (Shift 21)
Readability Score: 30/100
NBQnwB8by29twBL=

How to Use Cipher Identifier

  1. Paste any encoded string, cipher, or unknown token into the input box.
  2. The Multi-Decoder concurrently executes Base64, Hex, Binary, ROT13, 25 Caesar shifts, Base32, URL decode, A1Z26, and Morse code.
  3. Candidates are evaluated by an English language readability model and ranked by score (0-100).
  4. Click "Apply & Chain" to use any result as the input for a multi-stage decoding pipeline.

Practical Examples

Base64 Encoded Message

Ranks Base64 decoding first with highest readability score.

Input:
SGVsbG8gd29ybGQ=
Output:
Hello world (Base64 - Score: 95/100)

Hexadecimal Text

Identifies ASCII byte sequences and decodes instantly.

Input:
48656c6c6f
Output:
Hello (Hexadecimal - Score: 95/100)

ROT13 Substitution

Rotates alphabet characters by 13 positions.

Input:
Uryyb jbeyq
Output:
Hello world (ROT13 - Score: 95/100)

Common Mistakes & Troubleshooting

  • Assuming low-entropy strings score high: single words without spaces have fewer n-gram matches. Always inspect candidates even if scores are moderate.
  • Cipher identification is probabilistic: no algorithm can guarantee with 100% certainty what cipher generated a short ciphertext without key information.

Frequently Asked Questions

How does FormatFlow rank decoded candidates?

We evaluate decoded strings using a composite English-likeness score: measuring the ratio of printable characters, standard vowel frequency distribution (~38%), and dictionary word token density.

What is the Index of Coincidence (IC)?

The Index of Coincidence measures the probability that two randomly selected letters from a ciphertext are identical. Normal English text has an IC of ~0.067, while random or polyalphabetic ciphers have an IC closer to ~0.038.