• October 2, 2015
• Posted by: Syed Shujaat
• Category: Cisco, Networking Solutions

1. Crypto Key Generate Rsa Modulus 1024 Not Working In Packet Tracer
2. What Is Crypto Key Generate Rsa Modulus 1024

Use this command to generate RSA key pairs for your Cisco device (such as a router). keys are generated in pairs–one public RSA key and one private RSA key.

If your router already has RSA keys when you issue this command, you will be warned and prompted to replace the existing keys with new keys.

Why can't run crypto key generate rsa. The 3548 was end of sales in July 2002 (reference). They do not support ssh (only telnet for vty access) and thus do not have the capability to generate an RSA key. Specifically, with the most common padding scheme (PKCS#1 'old-style', aka 'v1.5'), the padding adds at least 11 bytes to the message, and the total padded message length must be equal to the modulus length, e.g. 128 bytes for a 1024-bit RSA key. Thus, the maximum message length is 117 bytes.

NOTE: Before issuing this command, ensure that your router has a hostname and IP domain name configured (with the hostname and ipdomain-name commands).

• The label is important, I'll tell you! In a minute why C1801(config)# crypto key generate rsa modulus 1024 label C1801 The name for the keys will be: C1801% The key modulus size is 1024 bits% Generating 1024 bit RSA keys, keys will be non-exportable.OK C1801(config)#.Jan 6 15:22:25.339:%SSH-5-ENABLED: SSH 1.99 has been enabled!
• How to factor RSA modulus given the public and private exponent? Ask Question. I posted a response on the crypto stack exchange answering the same question here. It uses the same approach as outlined in Boneh's paper, but does a lot more explanation as to how it actually works. Generate RSA key given modulus, public exponent and prime1.
• Router(config)# crypto key generate rsa label ms2 modulus 2048 on usbtoken0: The name for the keys will be: ms2% The key modulus size is 2048 bits% Generating 1024 bit RSA keys, keys will be on-token, non-exportable.
• Crypto Key Script will not work in config, but will manually. Y remote site customer has 3560 with 12.2(44)SE6, that if they run the command.
• Why can't run crypto key generate rsa The 3548 was end of sales in July 2002 ( reference ). They do not support ssh (only telnet for vty access) and thus do not have the capability to generate an RSA key.

You will be unable to complete the cryptokeygeneratersacommand without a hostname and IP domain name. (This situation is not true when you generate only a named key pair.)

Here are the steps to Enable SSH and Crypto Key setup : 2 config must requried for SSH

1 Setup Local VTY line User ID and password

router (Config) # Line VTY 0 15

router (Config-line)# login local

router (Config-line)# Exit

!!! create local login ID/Pass

router (Config)# username [loginid] password [cisco]

router (Config)# username loginid1 password cisco1

2. router (Config)# ip domain-name example.com

router (Config)# crypto key generate rsa

how many bits in the modulus [512] :1024

router (Config)# ip ssh version2

router (Config)# CTRL Z

This command is not saved in the router configuration; however, the RSA keys generated by this command are saved in the private configuration in NVRAM (which is never displayed to the user or backed up to another device) the next time the configuration is written to NVRAM.

Modulus Length

When you generate RSA keys, you will be prompted to enter a modulus length. The longer the modulus, the stronger the security. However, a longer modules take longer to generate (see the table below for sample times) and takes longer to use.

The size of Key Modulus range from 360 to 2048. Choosing modulus greater than 512 will take longer time.

Crypto Key Generate Rsa Modulus 1024 Not Working In Packet Tracer

Cisco IOS software does not support a modulus greater than 4096 bits. A length of less than 512 bits is normally not recommended. In certain situations, the shorter modulus may not function properly with IKE, so we recommend using a minimum modulus of 2048 bits.

Syntax Description : Optional Strings to embed with SSH Crypto key

What Is Crypto Key Generate Rsa Modulus 1024