How Do I Generate DSA SSH Keys ?

The Digital Signature Algorithm (DSA) was first proposed in the early 1990s by the US National Institute of Standards and Technology (NIST) as a standard for digital signatures. DSA was developed to provide a method for generating and verifying digital signatures that was more efficient than existing methods, such as RSA.

In 1994, the US government adopted DSA as a standard for use in digital signatures on government documents. DSA was also included as part of the Secure Hash Standard (SHS), which defined a standard method for generating cryptographic hashes. The combination of DSA and SHS provided a secure and efficient method for generating and verifying digital signatures.

DSA was originally designed to work with the SHA-1 hashing algorithm, which was considered secure at the time. However, in recent years, SHA-1 has been found to be vulnerable to collision attacks, which has led to the development of newer hashing algorithms, such as SHA-256 and SHA-3.

While DSA is still widely used for digital signatures, it is now considered less secure than other algorithms, such as RSA and ECDSA. In fact, the use of DSA has been discouraged by some security experts, and many modern cryptographic systems have stopped supporting it altogether. For example, OpenSSH, one of the most widely used SSH clients and servers, no longer supports DSA keys by default and recommends using RSA or ED25519 keys instead.

Here's an example of generating a DSA SSH key pair using `ssh-keygen`:

ssh-keygen -t dsa -b 1024 -C "your_email@example.com"

In this command, we're specifying the following options:

- `-t dsa`: This option specifies that we want to generate a DSA key pair.

- `-b 1024`: This option specifies the key size in bits. In this case, we're generating a key that is 1024 bits long. Note that DSA keys are typically smaller than RSA keys of equivalent strength, so a 1024-bit DSA key provides roughly the same level of security as a 2048-bit RSA key.

- `-C "your_email@example.com"`: This option adds a comment to the key, which is useful for identifying the key owner or providing some context for the key.

When you run this command, `ssh-keygen` will generate a DSA SSH key pair with a key size of 1024 bits and add a comment to the public key indicating the email address of the key owner. The private key will be saved to a file in your local `.ssh` directory, while the public key will be saved to a file with the same name as the private key, but with a `.pub` extension.

More about : SSH-KEYGEN , SSH-COPY-ID , RSA , DSA & ECDSA