About Generate HOTP
The HMAC-based One-Time Password algorithm (HOTP) is an algorithm that computes a one-time password from a shared secret key and an incrementing counter. It has been adopted as Internet Engineering Task Force standard RFC 4226, is the cornerstone of Initiative For Open Authentication (OAUTH), and is used in a number of two-factor authentication systems. Enter the secret as the input or leave it blank for a random secret to be generated. The secret must be a valid base32 string (characters A–Z and 2–7).
Input: binary bytes (text input uses UTF-8; a file retains its original bytes). Output: text.
Format reference: Generate HOTP 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 |
|---|---|---|
| Name | "Account" | Required |
| Code length | 6 | Minimum: 6. Maximum: 8. Integer |
| Counter | 0 | Minimum: 0. Integer |
Input
JBSWY3DPEHPK3PXP
Result
URI: otpauth://hotp/Account?secret=JBSWY3DPEHPK3PXP&algorithm=SHA1&digits=6&counter=0 Password: 282760
Parameters
| Parameter | Default value | Input and choices |
|---|---|---|
| Name | "Account" | Required |
| Code length | 6 | Minimum: 6. Maximum: 8. Integer |
| Counter | 0 | Minimum: 0. Integer |
Before interpreting the result
These tools have specialized conventions. Read the operation description and parameter choices before interpreting the result.
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.