SSH key creation and login(PuTTY version)

National Institutes of Natural Sciences
Okazaki Research Facilities
Research Center for Computational Science (RCCS)(Verified with PuTTY 0.80)

Changelog• Jul 10, 2019
• Feb 2, 2021
• May 24, 2021
• Jan 5, 2022
• Dec 20, 2022
• Jun 2, 2023
• Jan 18, 2024

First version
Update (recommended key types etc.)
Update for PuTTY 0.75
Verified with PuTTY 0.76
Update for PuTTY 0.78 and our new system
Minor fix of wording
Verified with PuTTY 0.80

Introduction
The aim of this document is to explain how to login to RCCS
supercomputer using PuTTY and its utility PuTTYgen.

Table of Contents• Install PuTTY• SSH key creation• Register public key• LoginInstall PuTTY
PuTTY can be downloaded from the following site:
https://www.chiark.greenend.org.uk/~sgtatham/putty/
The latest version of PuTTY can be downloaded at:https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html
MSI (Windows Installer) version is recommended.
We will use PuTTY and PuTTYgen.
If you already have PuTTY but not PuTTYgen, please install standalone
version of PuTTYgen (puttygen.exe) from the link in “Alternative binaryfiles” section of the download site.

SSH key creation (1)Launch PuTTYgen. If you installed MSI installer version,PuTTYgen can be found in Start Menu.

SSH key creation (2)RCCS recommends following types of keys.

choose Ed448!
- Ed25519 (select EdDSA of 255 bits) Don’t
Login servers don’t support that!
- ECDSA (256, 384, or 521 bits)- RSA 4096 bits (select RSA & modify number at lower right to 4096)
You need PuTTY 0.75 or later
Choose Ed25519 if you have no preference.
to use RSA key!

Click to generate key(After clicking “Generate”, move
mouse cursor around to proceed)

Select key type
Choose key length (RSA, ECDSA, EdDSA)

SSH key creation (3)Once key generation finished, new items will be shown in the window.

RCCS recommends
passphrase of 10
or more characters andcontaining all thefollowing 4 types.
- lower-case character- upper-case character- number- symbolThis is the public key
we need. You shouldsave this key in a file.
(Please copy whole thekey. This window isoften too small for some
types of keys.)

Click to save theprivate key.
You might want to choose
easy-to-understandfilename such asrccs.ppk or ccfep.ppk.

- Generated private key file must be kept secret.
- OpenSSH type private key can be obtained from “Conversions” menu (if needed).
- Public key can be restored from the private key; try “Load” button.
- If you lost the private key, you need to generate new one...

Register Public Key
Before login, you need to register the public key.
The procedure of the public key registration is available
from the following link.
https://ccportal.ims.ac.jp/en/account/

Don’t use the key from “Save public key” button of PuTTYgen.
Key displayed at “Public key for pasting into OpenSSH...”part of PuTTYgen window is the one what we expect.

The private key file must be kept secret.

Login (1)Did you register public key? OK, let’s launch PuTTY.

Login (2)In [Session], type “ccfep.ims.ac.jp” in the Host Name box.

Login (3)Move to [Connection] -> [Data] and fill your ID in the username box.

User ID (three letter ID
given by RCCS)(This step can be skipped. In that case, you will be asked upon connection.)

Login (4)Move to [Connection] -> [Data] -> [SSH] -> [Auth] -> [Credentials] andspecify private key (.ppk file)specify private key file generated
with PuTTYgen

If [Credentials] menu item does not exist, the private key file field can be found in[Connection] -> [Data] -> [SSH] -> [Auth] menu item.

Login (5)Move to [Session], save settings, and then login.

Give a name for this connection
Click to saveinto the list

Let’s login!

Login (6)Upon first connection, alert message will be shown.
Check the fingerprint; this mustmatch with either of the fingerprintin the list below.

Go ahead if the server fingerprint is valid.
・ad:de:79:30:81:b0:b1:6a:17:f5:6f:ea:f4:b4:3b:de (MD5)・e3:a9:bb:6f:e4:a9:37:fd:98:14:54:16:3c:81:2d:aa (MD5)Fingerprints ・07:7e:df:7b:16:47:a8:f5:7c:48:b0:a3:d3:86:71:6a (MD5)of valid
server keys ・wnEM30z4AxyDJ9XI/DdGr2PlNeoivFRR8v5krXHEmdU (SHA256)
・0KL38Yn/kBee1pAuxyKwenEwXjtPxr9ZElolfVqXvbI (SHA256)
・Nhg+9Lgj3XeuW//A/j7jqgUJlIxWehryCtStIp1Dirs (SHA256)

Login (7)You will be asked passphrase of private key. Type it.

Login (8)Once you typed correct passphrase, login to RCCS login
server will be granted.

Note: if you launch Pageant and your key is registered, passphrase won’t beasked upon connection. (You need to type passphrase upon registration to Pageant.)