About Colossus
Colossus is the name of the world's first electronic computer. Ten Colossi were designed by Tommy Flowers and built at the Post Office Research Labs at Dollis Hill in 1943 during World War 2. They assisted with the breaking of the German Lorenz cipher attachment, a machine created to encipher communications between Hitler and his generals on the front lines. To learn more, Virtual Colossus, an online, browser based simulation of a Colossus computer is available at virtualcolossus.co.uk. A more detailed description of this operation can be found here.
Input: text. Output: structured JSON.
Format reference: Colossus background and specification
Example
Use “Try example” to load this public sample and its settings, then run it.
Settings used in this example
| Parameter | Example value | Input and choices |
|---|---|---|
| Pattern | KH Pattern | KH Pattern, ZMUG Pattern, BREAM Pattern |
| QBusZ | Z | , Z, ΔZ |
| QBusΧ | | , Χ, ΔΧ |
| QBusΨ | | , Ψ, ΔΨ |
| Limitation | None | None, Χ2, Χ2 + P5, X2 + Ψ1, X2 + Ψ1 + P5 |
| K Rack Option | "Select Program" | Select Program, Top Section - Conditional, Bottom Section - Addition, Advanced |
| Program to run | Letter Count | , Letter Count, 1+2=. (1+2 Break In, Find X1,X2), 4=5=/1=2 (Given X1,X2 find X4,X5), /,5,U (Count chars to find X3) |
| R1-Q1 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R1-Q2 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R1-Q3 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R1-Q4 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R1-Q5 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R1-Negate | false | On or off |
| R1-Counter | | , 1, 2, 3, 4, 5 |
| R2-Q1 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R2-Q2 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R2-Q3 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R2-Q4 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R2-Q5 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R2-Negate | false | On or off |
| R2-Counter | | , 1, 2, 3, 4, 5 |
| R3-Q1 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R3-Q2 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R3-Q3 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R3-Q4 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R3-Q5 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R3-Negate | false | On or off |
| R3-Counter | | , 1, 2, 3, 4, 5 |
| Negate All | false | On or off |
| Add-Q1 | false | On or off |
| Add-Q2 | false | On or off |
| Add-Q3 | false | On or off |
| Add-Q4 | false | On or off |
| Add-Q5 | false | On or off |
| Add-Equals | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| Add-Counter1 | false | On or off |
| Add Negate All | false | On or off |
| Total Motor | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| Set Total | 0 | Number |
| Fast Step | | , X1, X2, X3, X4, X5, M37, M61, S1, S2, S3, S4, S5 |
| Slow Step | | , X1, X2, X3, X4, X5, M37, M61, S1, S2, S3, S4, S5 |
| Start Χ1 | "1" | Number |
| Start Χ2 | "1" | Number |
| Start Χ3 | "1" | Number |
| Start Χ4 | "1" | Number |
| Start Χ5 | "1" | Number |
| Start M61 | "1" | Number |
| Start M37 | "1" | Number |
| Start Ψ1 | "1" | Number |
| Start Ψ2 | "1" | Number |
| Start Ψ3 | "1" | Number |
| Start Ψ4 | "1" | Number |
| Start Ψ5 | "1" | Number |
Input
CTBKJUVXHZ-H3L4QV+YEZUK+SXOZ/N
Result
The result is structured data. Inspect its fields in the output.
Parameters
| Parameter | Default value | Input and choices |
|---|---|---|
| Pattern | KH Pattern | KH Pattern, ZMUG Pattern, BREAM Pattern |
| QBusZ | | , Z, ΔZ |
| QBusΧ | | , Χ, ΔΧ |
| QBusΨ | | , Ψ, ΔΨ |
| Limitation | None | None, Χ2, Χ2 + P5, X2 + Ψ1, X2 + Ψ1 + P5 |
| K Rack Option | "Select Program" | Select Program, Top Section - Conditional, Bottom Section - Addition, Advanced |
| Program to run | | , Letter Count, 1+2=. (1+2 Break In, Find X1,X2), 4=5=/1=2 (Given X1,X2 find X4,X5), /,5,U (Count chars to find X3) |
| R1-Q1 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R1-Q2 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R1-Q3 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R1-Q4 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R1-Q5 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R1-Negate | false | On or off |
| R1-Counter | | , 1, 2, 3, 4, 5 |
| R2-Q1 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R2-Q2 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R2-Q3 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R2-Q4 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R2-Q5 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R2-Negate | false | On or off |
| R2-Counter | | , 1, 2, 3, 4, 5 |
| R3-Q1 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R3-Q2 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R3-Q3 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R3-Q4 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R3-Q5 | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| R3-Negate | false | On or off |
| R3-Counter | | , 1, 2, 3, 4, 5 |
| Negate All | false | On or off |
| Add-Q1 | false | On or off |
| Add-Q2 | false | On or off |
| Add-Q3 | false | On or off |
| Add-Q4 | false | On or off |
| Add-Q5 | false | On or off |
| Add-Equals | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| Add-Counter1 | false | On or off |
| Add Negate All | false | On or off |
| Total Motor | "" | Up (.), Centre, Down (x). Escape sequences such as \n, \r and \t are supported |
| Set Total | 0 | Number |
| Fast Step | | , X1, X2, X3, X4, X5, M37, M61, S1, S2, S3, S4, S5 |
| Slow Step | | , X1, X2, X3, X4, X5, M37, M61, S1, S2, S3, S4, S5 |
| Start Χ1 | 1 | Number |
| Start Χ2 | 1 | Number |
| Start Χ3 | 1 | Number |
| Start Χ4 | 1 | Number |
| Start Χ5 | 1 | Number |
| Start M61 | 1 | Number |
| Start M37 | 1 | Number |
| Start Ψ1 | 1 | Number |
| Start Ψ2 | 1 | Number |
| Start Ψ3 | 1 | Number |
| Start Ψ4 | 1 | Number |
| Start Ψ5 | 1 | Number |
Before interpreting the result
Use the exact key encoding, mode, padding and IV expected by the source system. Historical ciphers are useful for learning and analysis. Encoding alone provides no confidentiality.
How to use this page
- Paste your input or open a local file.
- Adjust tool options if needed, then choose Run tool.
- Copy the result or download the original output bytes.
Inputs and results are not added to the public catalogue or saved in the URL. Processing happens in your browser; HTTP Request and DNS over HTTPS send the requests you explicitly run. Files up to 128 MiB can be opened; decompression and image tools may have smaller processing limits. Large results have a shortened preview. Text and HTML downloads use UTF-8; binary downloads preserve output bytes. Pasted text follows browser newline handling; open a file when exact input bytes matter.