118 votes
Accepted

Why OpenSSH deprecated DSA keys

This is a good question. The dedicated page from OpenSSH only says: OpenSSH 7.0 and greater similarly disables the ssh-dss (DSA) public key algorithm. It too is weak and we recommend against its use. ...
Tom Leek's user avatar
  • 173k
18 votes
Accepted

What are the differences between the RSA, DSA, and ECDSA keys that SSH uses?

What are these files for? These are your host keys uniquely identifying your host. When OpenSSH is started for the first time, it will generate these keypairs. When an SSH client connects to your ...
forest's user avatar
  • 66.7k
12 votes

Why OpenSSH deprecated DSA keys

https://bugzilla.mindrot.org/show_bug.cgi?id=1647 has the reasoning behind the restricting DSA keys to 1024 bits, but basically: RFC4253 section 6.6 requires the SHA1 hash (160 bits) for ssh-dss (ie ...
Darren Tucker's user avatar
10 votes

Should DSA keys be considered deprecated?

OpenSSH's decision appears to be motivated by some sort of confusion that originates from their own code base; see this answer for an analysis. In SSH, DSA keys are deprecated because the people who ...
Tom Leek's user avatar
  • 173k
4 votes
Accepted

Can an attacker replace the hash of a download, a download, and the public key?

If the site with the instructions is compromised the attacker can replace all instructions. This means that he can specify a different key to use for verification or omit the verification information ...
Steffen Ullrich's user avatar
4 votes

Found DSA and RSA private keys hard-coded in a file during penetration testing. How to use them for SSH authentication?

If there are configuration files for ssh server, they are probably server host keys and you are not able to log in with then anywhere. Only to perform Man in The Middle attack, if you would be able to ...
Jakuje's user avatar
  • 5,759
3 votes

Generating a DER-encoded DSA public key of a particular file size

There are lots of things in an X.509 certificate other than the publickey whose sizes can be varied to pretty much anything you want, especially if you don't care about security: all the name fields, ...
dave_thompson_085's user avatar
3 votes

Is it safe if SSH and HTTPS server share the same RSA/DSA keys?

Just let the SSHD create some random keys for you. If either of the server software or the protocols reveals to be vulnerable in a way that could leak the private key, that would compromise both SSH ...
Esa Jokinen's user avatar
2 votes

RSA-1024 vs. DSA-1024: Claim DSA SSH key is much faster to brute force

Trying to brute force either a RSA or DSA key would be a losing proposition, there are far too many possibilities and there are far better attacks known. For properly implemented RSA the best-known ...
Peter Green's user avatar
  • 5,300
2 votes

Why OpenSSH deprecated DSA keys

186-3 (and -4) 4.2 says 'ordinarily should not' use a hash weaker than L,N That part says A hash function that provides a lower security strength than the (L, N) pair ordinarily should not be used. ...
dtucker's user avatar
  • 21
2 votes
Accepted

Does SSH support DSA with 2048 bit keys?

For the hash: Crossdupe https://crypto.stackexchange.com/questions/15051/why-does-openssh-use-only-sha1-for-signing-and-verifying-of-digital-signatures and https://crypto.stackexchange.com/questions/...
dave_thompson_085's user avatar
2 votes

How do I sign a short text message with ~/.ssh/id_{dsa,ecdsa,ed25519}?

For DSA, ECDSA using OpenSSL and using different functions and structures than for RSA. It won't work for ed25519 keys, because their operations are implemented in the openSSH itself. But you can ...
Jakuje's user avatar
  • 5,759
1 vote
Accepted

How can we ensure non-repudiation without a personal certificate (eg. using ID authentication)

Think you can apply Something You Know, Have, or Are authentication principle, right now many fintech business use many different "2 of 3" combinations on this, like password+phone authenticator, ...
gl4ssiest's user avatar
1 vote

Should I stop using DSA key algorithm self-signed certificates in production in favor of RSA Certificates?

RSA is generally considered to be a better idea simply because it is less fragile than DSA. When used properly, they are both equally secure. The problem stems from the fact that DSA signatures, if ...
forest's user avatar
  • 66.7k
1 vote

Found DSA and RSA private keys hard-coded in a file during penetration testing. How to use them for SSH authentication?

If they are in fact private keys with the corresponding public keys on the server setup for a user for SSH access, then you should be able to SSH presuming that public key access is enabled. If you ...
SilverlightFox's user avatar
1 vote

Impact analysis of CVE-2016-1000341 affecting BouncyCastle

TLDR: 1a. DSA signature generation is generating a signature (for data). As you quoted ... gain information about the signatures [sic - should have an apostrophe] k value and ultimately the ...
dave_thompson_085's user avatar
1 vote

Website uses an unsupported protocol. ERR_SSL_VERSION_OR_CIPHER_MISMATCH

Looks like you are missing which SSL protocol and in which order to use, also you must specify on which IP should SSL be listening. And eventually your virtual host with 443 should look like this: &...
Aleksandar Pavić's user avatar

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