Only what you need
Hashing no longer downloads the RSA and encryption logic, so each page starts faster.
Free Online Crypto Tools
Four focused tools for encryption, key generation, text encoding and hashing. Each one runs on its own page, in your browser, without uploading the text, the keys or the results.
Encrypt and Decrypt Text
Protect a message with AES, DES, 3DES, RC4, Rabbit or TripleDES using a secret key you control.
Open the encryption toolGenerate RSA Key Pair
Create a public and private key, export them as PEM, import existing keys and encrypt or decrypt text.
Open the RSA key generatorBase64, URL and Unicode
Encode and decode Base64, percent-encoded URLs and Unicode escape sequences in one place.
Open the text encoderHash and HMAC
Calculate MD5, SHA-1, SHA-256 and SHA-512 digests, or compute a keyed HMAC for signing.
Open the hash generator
What is inside
Pick the Tool for the Job
Each page keeps its own algorithm guide and examples, so there is nothing to configure first.
| Tool | Use it when | Reversible |
|---|---|---|
| Encrypt and Decrypt Text | You need confidentiality and can share a secret key with the recipient | Yes, with the key |
| Generate RSA Key Pair | You need a public key to encrypt and a private key to decrypt | Yes, with the private key |
| Base64, URL and Unicode | You need text to survive transport through a system that only accepts ASCII | Yes, by anyone |
| Hash and HMAC | You need a fingerprint to compare, or a keyed signature to verify | No |
Privacy: encryption, key generation, encoding and hashing all run with JavaScript in your browser. Plaintext, keys and digests are never sent to the 73hi server, and nothing is stored.
Why separate pages
Small Pages, Fast Answers
Every tool loads only the script and the library it actually needs.
Its own algorithm guide
Each page explains which algorithm to pick and what the output means for that tool.
One click between tools
The navigation strip at the top of every tool page links straight to the other tools in this category.
Private by default
No upload, no signup and no server-side storage of anything you type or generate.
Questions and answers
Crypto Tools FAQ
Are these crypto tools free?
Yes. Every crypto tool on 73hi is free to use with no signup and no daily limit.
Do the tools upload my text or my keys?
No. Encryption, key generation, encoding and hashing all run with JavaScript in your browser. Plaintext, keys and digests never reach the 73hi server.
Why is each tool on its own page?
Each tool now has a dedicated page with its own instructions, algorithm guide and FAQ, so it loads faster and is easier to find in search. The tools stay one click apart through the navigation strip at the top of every page.
Can 73hi recover a lost key or decrypt my data?
No. Keys and plaintext never leave your device and nothing is stored server-side, so there is nothing to recover.