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Cryptor (AES-256) — Examples

Cryptor in practice: encrypt, decrypt, wrong password, files, older formats, drag and drop, undo, and decrypting without the tool.

Back to overview: Cryptor (AES-256) · Open the live tool: www.jpkc.com/tools/cryptor/

This page shows Cryptor (AES-256) through concrete walkthroughs. The texts and passwords used are examples — for real secrets, use your own strong passwords, of course. How the individual functions work in detail is covered in the manual.

Example 1: Encrypt a text

Goal: turn a short confidential note into ciphertext.

  1. Generate a password — click the key icon next to the password field and pick Passphrase · 6 words. Cryptor fills in a passphrase such as crumb-velvet-unfold-stucco-lagoon-ripple, reveals it, and shows "strong ≈ 78 bits" above the field.
  2. Secure the password — use the copy button (Copy password) to move it into your password manager.
  3. Enter text — type the plaintext into the Message field, e.g. Meeting Friday 6 pm, back courtyard..
  4. Click Encrypt (or press Ctrl+Enter).

Result: the Message field now holds ciphertext starting with cryptor:v2:600000:, followed by a Base64 block. The status line reports "Encrypted · AES-256-GCM · 600,000 iterations" plus the duration, and a notice confirms "Message encrypted.". You can safely send this text by email or chat. Important: hand over the password separately, through a different channel.

Variant with your own password: if you type the password yourself, it stays hidden, and Cryptor wants it a second time in Repeat password as a check. If the two don't match, you get "The two passwords do not match." and nothing is encrypted. Reveal the password with the eye button and the repeat is no longer needed — after all, you can see what you typed.

Example 2: Decrypt a text

Goal: make received ciphertext readable again.

  1. Enter the password — type or paste exactly the password that was used to encrypt. No repeat is needed for decrypting.
  2. Paste the ciphertext — put the complete text, starting at cryptor:v2:, into the Message field. If your mail client wrapped it across several lines, that doesn't matter.
  3. Click Decrypt.

Result: Cryptor recognizes format v2, verifies the authentication tag, and returns the plaintext if the password is correct ("Message decrypted."). The status line reports "Decrypted · format v2 · 600,000 iterations". You read Meeting Friday 6 pm, back courtyard. again.

Example 3: Wrong password

Goal: understand what happens on a typo or a wrong password.

  1. Paste valid ciphertext into the Message field.
  2. Enter a wrong password.
  3. Click Decrypt.

Result: decryption fails and "Wrong password — or the encrypted text was changed or is incomplete." appears. The field content stays unchanged — so you don't lose the ciphertext. This is down to GCM mode: if the derived key is wrong, the authentication tag doesn't match, and Cryptor rejects the decryption instead of producing meaningless plaintext. Often the same message also appears if the ciphertext was corrupted or copied incompletely. If that breaks the Base64 block, Cryptor reports "This is not encrypted text from Cryptor (or it was damaged while copying)." instead, and if the block of a v2 text ends up too short, "The encrypted text is incomplete (too short).". If the field holds something else entirely, the first of these two messages appears before Cryptor even starts computing. If, on the other hand, exactly the header cryptor:v2:600000: is missing, Cryptor takes the remaining Base64 block for the older format v1, works through both v1 iteration counts, and then also reports "Wrong password — or the encrypted text was changed or is incomplete.". In that case, check whether you copied the whole text.

Example 4: Load, encrypt, and save a file

Goal: encrypt the content of a text file and save the result as a file.

  1. Click Open and pick a text file (e.g. .txt, .enc, or .aes, at most 20 MB). Its content lands in the Message field. (Alternatively, drag the file straight onto the field — see Example 6.)
  2. Enter (and repeat) or generate a password.
  3. Click Encrypt — the plaintext is replaced by the ciphertext.
  4. Click Save — Cryptor recognizes the ciphertext and downloads it as encrypted.txt.

Result: you have an encrypted file to archive or send. To restore it, load it later with Open, enter the password, and click Decrypt. A subsequent Save then stores the decrypted content as plaintext.txt — so you won't mix up the two files.

If you accidentally pick an image or a PDF, Cryptor refuses it with "… is not a text file. Cryptor encrypts text only." instead of mangling it as text.

Example 5: Read an old (legacy) message

Goal: decrypt ciphertext from an earlier version of the tool.

  1. Paste the old text into the Message field. Depending on its age, it starts with U2FsdGVkX1… (legacy, before 2026) or is bare Base64 without the cryptor: prefix (format v1, January to October 2026).
  2. Enter the password from back then.
  3. Click Decrypt.

Result: Cryptor identifies the format by itself — for v1 it tries both iteration counts used at the time, one after the other. The status line names "format v1 (older)" or "legacy format (OpenSSL / gibberish-aes)", and you see the hint "Decrypted an older format. Encrypt it again to upgrade it to the current, stronger format.". Follow it: click Encrypt right after (with a hidden password, fill in Repeat password first) to secure the plaintext in format v2 with 600,000 iterations. The old formats can no longer be produced — only read.

Example 6: Load a file via drag and drop

Goal: work without the file dialog.

  1. Drag a text file from your file manager onto the Message field. While you hold it over the field, it highlights.
  2. Drop the file — its text content is loaded as UTF-8, and a notice names the file ("Dropped: …").
  3. Carry on as usual: enter a password, then press Ctrl+Enter. If the content is ciphertext, Cryptor decrypts it; otherwise it encrypts.

Result: the file content sits in the field, ready to encrypt or decrypt — a quick path when you're already in the file manager.

Example 7: Take a step back

Goal: recover content you overwrote by accident.

  1. Encrypt some plaintext (as in Example 1).
  2. Accidentally load the wrong file with Open — the ciphertext is gone from the field.
  3. Click Undo (or press Ctrl+Z, as long as you haven't typed in the field).

Result: the ciphertext is back in the field ("Restored the previous state."). Another Undo brings back the plaintext from before encryption. Cryptor remembers up to 20 such steps — including the password, so even an accidental Clear is no drama. Reload the page, though, and this history is gone.

Example 8: Decrypt without Cryptor

Goal: read ciphertext on the command line — say, on a server without a browser.

  1. In the tool, go to the Format & decrypting without this tool card, select the Python tab, and grab the script with its copy button.
  2. Save it locally as decrypt.py, install the library once, and put the ciphertext next to it as message.txt:
pip install cryptography
python3 decrypt.py message.txt
  1. Enter the password when the script asks for it.

Result: the plaintext appears in the terminal. Equivalent scripts for Node.js (18 or later, no packages) and PHP (7.1 or later with OpenSSL) sit in the neighboring tabs; for legacy texts, the Older formats tab provides an openssl command. Best keep the script right next to your encrypted archives — then you don't depend on this website.

More on the individual functions is in the manual; strategic notes and pitfalls are in the tips & tricks. To dive straight in, open the tool.