The algorithm is selected using the -t option and key size using the -b option. The following commands illustrate: ssh-keygen -t rsa -b 4096 ssh-keygen -t dsa ssh-keygen -t ecdsa -b 521 ssh-keygen -t ed25519 Specifying the File Name. Normally, the tool prompts for the file in which to store the key.
· $ ssh-keygen -t RSA Generate RSA Key with Ssh-keygen Generate RSA Key To Different Path. By default RSA key is generated into user home directory ~/.ssh/id_rsa . We can change this default directory during the generation or by providing the path as parameter. We will use -f option in order to change path and file name. We will create key named ...
For RSA keys, the minimum size is 768 bits and the default is 2048 bits. Generally, 2048 bits is considered sufficient. DSA keys must be exactly 1024 bits as specified by FIPS 186-2.
· Generating public keys for authentication is the basic and most often used feature of ssh-keygen. ssh-keygen can generate both RSA and DSA keys. RSA keys have a minimum key length of 768 bits and the default length is 2048. When generating new RSA keys you should use at least 2048 bits of key length unless you really have a good reason for using a shorter and …
ssh-keygen will by default write keys in an OpenSSH-specific format. This format is preferred as it offers better protection for keys at rest as well as allowing storage of key comments within the private key file itself. ... For RSA keys, the minimum size is 1024 bits and the default is 3072 bits. Generally, 3072 bits is considered sufficient ...
If the key is available, the top half of the key will display the key length. A Hex to ASCII converted can be used to get this information. A pregenerated key in EXOS shows a value of 2048 bit as shown below which would be default.---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----Subject: root Comment: "2048-bit DSA key, root, Fri Jul 24 18:21:20 2015"
· Time has been RSA’s greatest ally and greatest enemy. First published in 1977, RSA has the widest support across all SSH clients and languages and has truly stood the test of time as a reliable key generation method. Subsequently, it has also been subject to Moore’s Law for decades and key bit-length has grown in size.
So the key has type RSA, and its modulus has length 257 bytes, except that the first byte has value "00", so the real length is 256 bytes (that first byte was added so that the value is considered positive, because the internal encoding rules call for signed integers, the first bit defining the sign). 256 bytes is 2048 bits.
Some people have eyes that see not and ears that hear not, but never tongues that talk not.