# Encryption of 7 byte of data, output must be 7 byte [duplicate]

I'm looking for a cryptographic algorithm that inputs and outputs are both 7 bytes. Is there any such algorithm?

• I'd suggest checking out some of our earlier format-preserving encryption questions, such as crypto.stackexchange.com/questions/504/…, crypto.stackexchange.com/questions/20035/… and maybe crypto.stackexchange.com/questions/48808/…. Jul 17 '19 at 16:26
• CTR mode. ${}{}$ Jul 17 '19 at 17:01
• Are there any security constraints in terms of bits? (i.e. given that 7 times 8-bits per byte would be a total of 56-bits with that much potential maximum security) Jul 17 '19 at 18:53
• @kelalaka: That only works if you have an (implicit) unique nonce to go with each piece of data to be encrypted (or if you only ever encrypt one piece of data per key). Jul 17 '19 at 21:17
• Reduced-size Feistel network based on keyed XOF. Jul 18 '19 at 1:13