Encryption and decryption of large text strings

cnrealm

I need a method or source code that can encrypt and decrypt large text. This text string may be an entire article. I searched on the Internet for a day and tried for a day, but I didn't find a suitable one. It seems that they can only encrypt 64-bit long strings, or I don't understand.
In addition, there is no encryption and decryption of any files.

shihaoly

You can use 64-bit encryption as a block.

boxer2005

Cryptography

wenbinjiao

Halo, is there any algorithm that can only encrypt 64-bit long strings?
LZ didn't understand, go on to study

cnrealm

Is it all handled in a circular way?

40668477

With des

40668477

There are 64-bit keys and 128-bit ...

 64-bit is still very safe. If the performance requirements are not high, you can consider 128 (the CPU speed is getting faster and faster during the security period)

 The encryption algorithm is not understandable through a program, but it is better to read a book. I have read some basic teaching materials abroad.

 My book is: cryptography and network security principles and practice
  seconde edition

40668477

The National Bureau of standards uses DES. Data is encrypted in 64-bit blocks and the key length is 56-bit. Transform 64-bit input into 64-bit output.