https://github.com/listx/floop

Simple, fast, multithreaded PRNG
https://github.com/listx/floop

Last synced: about 1 month ago
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Simple, fast, multithreaded PRNG

• Host: GitHub
• URL: https://github.com/listx/floop
• Owner: listx
• License: other
• Created: 2014-06-24T07:03:23.000Z (over 10 years ago)
• Default Branch: master
• Last Pushed: 2015-03-09T07:14:29.000Z (almost 10 years ago)
• Last Synced: 2024-11-07T01:07:41.649Z (3 months ago)
• Language: C
• Homepage:
• Size: 156 KB
• Stars: 0
• Watchers: 3
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# FLOOP

## What is it?

Floop is a pseudorandom number generator that outputs a stream of bytes to STDOUT.

Its main purpose is to be used as a program to do (hopefully) secure wipes of storage devices such as hard drives and flash media.

## Usage

Floop outputs *only to STDOUT*; if you want to write to a file, either pipe it to `dd`, or redirect STDOUT with `>`.

### Examples

Use 8 threads, with each thread generating 0x200000 elements of 8-byte words, and control it with `dd`.

```

./floop --threads 8 --thread-buf 0x200000 --count 0 | dd of=/some/file/or/device count=10 bs=128M

```

The `--thread-buf` flag controls how many 8-byte words a thread will generate per iteration.

So, if `--thread-buf` is set to 2, each thread defined by `--threads` will generate 2 8-byte words, or 16 bytes, per iteration.

The iteration is controlled with `--count`, which when set to 0 will make floop run forever; this is why we pipe it to `dd` above.

Using `dd` is also useful because it gives you information on how fast it was able to write the bytes to the destination.

#### Actual Use Case

The following was on a Western Digital Passport Ultra 1TB Portable External USB 3.0 Hard Drive (WDBZFP0010BBL-NESN).

```

 $ floop -t 8 -b 0x200000 -c 0 | pv -bartpes 1000170586112 | dd bs=128M of=/dev/sde

dd: error writing ‘/dev/sde’: No space left on device==========================================================> ] 99% ETA 0:00:00

 931GiB 3:28:57 [76.1MiB/s] [76.1MiB/s] [======================================================================>] 100%

0+9287529 records in

0+9287528 records out

1000170586112 bytes (1.0 TB) copied, 12592.6 s, 79.4 MB/s

```

The speed is not impressive, because of the slow speed of the drive itself.

In comparison, using openssl (using AES encryption to encrypt a stream of 0s and using that data as output) with `openssl enc -aes-256-ctr -pass pass:"$(dd if=/dev/random bs=128 count=1 2>/dev/null | base64)" -nosalt