Encrypt/Decrypt is a free online tool for encrypting and decrypting text using AES, DES, Triple DES, Rabbit, RC4, and RC4Drop. All processing runs in your browser — no data is sent to any server.
What is encryption?
Encryption transforms readable plaintext into unreadable ciphertext using a cryptographic algorithm and a secret key. Only someone with the correct key can decrypt the ciphertext back to the original plaintext. This tool supports symmetric encryption — the same key encrypts and decrypts.
Common Use Cases
Encrypting sensitive text before sharing it — the recipient needs the same passphrase to decrypt.
Verifying encryption output or decrypting ciphertext you received, without installing any software.
Testing and learning how different algorithms (AES, DES, RC4) behave with various block modes and padding schemes.
How to Encrypt or Decrypt Text
- 1
Choose your algorithm
- 2
Enter your text and passphrase
- 3
Encrypt or decrypt
AES
The Advanced Encryption Standard (AES) is a U.S. Federal Information Processing Standard (FIPS). It was selected after a 5-year process where 15 competing designs were evaluated.
DES, Triple DES
DES is a previously dominant algorithm for encryption, and was published as an official Federal Information Processing Standard (FIPS). DES is now considered to be insecure due to the small key size.
Triple DES applies DES three times to each block to increase the key size. The algorithm is believed to be secure in this form.
Rabbit
Rabbit is a high-performance stream cipher and a finalist in the eSTREAM Portfolio. It is one of the four designs selected after a 3 1/2-year process where 22 designs were evaluated.
RC4, RC4Drop
RC4 is a widely-used stream cipher. It's used in popular protocols such as SSL and WEP. Although remarkable for its simplicity and speed, the algorithm's history doesn't inspire confidence in its security.
It was discovered that the first few bytes of keystream are strongly non-random and leak information about the key. We can defend against this attack by discarding the initial portion of the keystream. This modified algorithm is traditionally called RC4-drop.
By default, 192 words (768 bytes) are dropped, but you can configure the algorithm to drop any number of words.