Rabbit is a high-speed stream cipher first proposed at the FSE workshop in 2003.
Rabbit uses a 128-bit key and a 64-bit initialization vector. The core component of this encryption algorithm is a bit stream generator that encrypts 128 message bits with each iteration.

Operation Modes

• CBC: Cipher Block Chaining, where plaintext is divided into fixed-size blocks and encrypted sequentially. Each block (group) is XORed with the encrypted data of the previous block before encryption. To ensure uniqueness of each message, the first data block is XORed with an initialization vector (IV) before encryption. CBC mode is a widely used encryption mode, but its main drawback is that encryption is sequential and cannot be parallelized. Like ECB, message blocks must be padded to a multiple of the block size.

Padding Modes

• None: No padding
• PKCS7: Padding consists of a byte sequence, with each byte padded to the length of the byte sequence
• Zeros: Padding consists of bytes set to zero
• ANSIX923: Padding consists of a byte sequence, where the last byte of the sequence indicates the length and other bytes are filled with zeros
• ISO10126: Padding consists of a byte sequence, where the last byte of the sequence indicates the length and other bytes are filled with random data

For block symmetric encryption algorithms, some operation modes require the byte length of plaintext data to be a multiple of the block size, so we must pad the plaintext data before encrypting it.

Key(IV) Text Or Hex

• Text represents the text format and is encoded in UTF-8 before being converted to a byte[] array.
• Hex represents the hexadecimal format, and the input will be converted from a hexadecimal string to a byte[] array before encryption.

Character Set and Format encryption instructions

• First Scenario, taking DES encryption as an example: select "Text" from the key dropdown, enter "12345678" as the Key, leave the IV empty; encrypt the string "中国abc". Choose character set "UTF-8". The encryption output is in hexadecimal format, select "Hex" from the format dropdown. The encrypted output result is "C886FF3D9DCB37FA1FA0EAD95889DF3E". View Example
• Another Scenario, still using DES encryption as an example: select "Text" from the key dropdown, enter "12345678" as the Key, leave the IV empty; encrypt hexadecimal data, for example [0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08]. Choose character set "Hex". The encryption output is in Base64 format, select "Base64" from the format dropdown. The encrypted output result is "up/vqMd1Eq4d/TFcc22l3Q==". View Example

Character Set and Format decryption instructions

• First Scenario, using DES decryption as an example: select "Text" from the key dropdown, enter "12345678" as the Key, leave the IV empty; decrypt the hexadecimal string "C886FF3D9DCB37FA1FA0EAD95889DF3E". Therefore, select "Hex" from the format dropdown for decryption, and the data encoding after decryption is "UTF-8". Choose character set "UTF-8". The decrypted string is "中国abc". View Example
• Another Scenario, still using DES decryption as an example: select "Text" from the key dropdown, enter "12345678" as the Key, leave the IV empty; decrypt the Base64 string "up/vqMd1Eq4d/TFcc22l3Q==". Therefore, select "Base64" from the format dropdown for decryption, and there is no additional encoding after decryption, as it is hexadecimal data. Choose character set "Hex" (selecting "UTF-8" would result in garbled text). The final decrypted string is "0102030405060708". View Example