Screenshot of AS-ISAAC64 1.10
A command line program for encryption and decryption of files. The program uses a 2048-bit ISAAC-64 with a 256-bit nonce .
The program uses a key strengthening algorithm , this increases the security.
The program stores an encrypted checksum  of the original file, which is verified at decryption.
The program delivers an ErrorLevel code  which indicates success (0) or failure (1).
The speed is measured and the program will display the results for you when it's done.
Use the parameter "-NoPercent" to display the number of Bytes that has been processed instead of percent.
Important information: Save the downloaded program if you have information encrypted with it. I do not guarantee compatibility between different versions/revisions of the program.
Speed Reference: Approximately 80 MB/sec. (Intel Core i3-2120) 
> Download AS-ISAAC64 1.10 (Zip, 503 kB)
Revision Date: 2019-12-08.
Unicode Support: Yes.
Program Type: Portable, x64.
Operating System(s): Windows 7 (SP1+), 8.1 and 10. (Also Windows Server 2012 R2 and 2016.)
Language(s): Only English.
 In this program, a 256-bit random nonce is used, which is fetched from Microsoft CryptoAPI. (RANDOM.DLL)
 The key strengthening algorithm is using SHA3-512 and executes 131,072 times for each password. (KSA.DLL)
 The encrypted checksum is a CRC-64-ECMA.
 The ErrorLevel code can be useful when calling from batch files or other programs.
 The speed reference is measured under good conditions, a fast disk and a pretty large file.