Re: MD5 is slow

[Jay Acuna via NANOG <nanog () lists nanog org>]

On Wed, Sep 10, 2025 at 8:20 AM nanog--- via NANOG
<nanog () lists nanog org> wrote:
> A hash is also way faster than 5ms to compute. I suggest doing your own benchmark. Run it on an old raspberry pi or 
> one of Amazon's cheapest ARM servers to be sure it's comparable to typical router CPU hardware.

Perfect.  The CPU of a Pi as in an ARMv7 is far too low to efficiently
bear the load involved
in IGP calculations for a large network.  Let alone a full BGP table.
Network vendors have
chosen and will choose procs and application-specific circuits
adequate to the task for MD5 or SHA2.
This is not a problem.  If the ARM cannot hash quickly;  the gear will
likely contain logic circuits
and software modules optimized for efficient hashing to achieve
acceptable latency.

Even that underpowered Pi Zero seems capable hashing within a 1 millisecond
interval just fine using standard libraries.

SHA-3 is not operationally relevant, but the slowest of those algorithms
still speed measures as hashing 4 Kilobytes within a millisecond interval.


$ ssh piuser@mordor.elysium 'sudo apt -y install botan >/dev/null 2>&1;
 tail -15 /proc/cpuinfo; botan speed --buf-size=1500 --msec=1 SHA-256
SHA-384 SHA-3'
Enter passphrase for key '/home/shadowfax/.ssh/yubikey5ec01':
Confirm user presence for key *
User presence confirmed
processor : 3
model name : ARMv7 Processor rev 4 (v7l)
BogoMIPS : 38.40
Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva
idivt vfpd32 lpae evtstrm crc32
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 4

Hardware : BCM2835
Revision : 902120
Serial : 000000002d61f097
Model : Raspberry Pi Zero 2 W Rev 1.0

SHA-256 hash buffer size 1500 bytes: 24.384 MiB/sec (0.026 MiB in 1.056 ms)
SHA-384 hash buffer size 1500 bytes: 7.719 MiB/sec (0.009 MiB in 1.112 ms)
SHA-3(512) hash buffer size 1500 bytes: 4.254 MiB/sec (0.004 MiB in 1.009 ms)
$

--
-JA
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