What is the Difference Between SSH1 and SSH2?
🆚 Go to Comparative Table 🆚The major differences between SSH1 and SSH2 fall into two main categories: technical and licensing.
Technically, SSH2 uses different encryption and authentication algorithms compared to SSH1. SSH1 supported four encryption algorithms, two of which had been found to be insecure. SSH2 is a complete rewrite of the original protocol and incorporates built-in protections against various attacks.
In terms of licensing, the new SSH2 protocol is designed to avoid intellectual property claims, while SSH1 used patented technologies.
Some other differences between SSH1 and SSH2 include:
- SSH1 and SSH2 encrypt at different parts of the packets.
- SSH1 uses server and host keys to authenticate systems, while SSH2 only uses host keys.
- SSH2 is more secure than SSH1.
Due to these differences, SSH1 and SSH2 are not compatible with each other, meaning that they cannot communicate or interoperate. It is recommended to use SSH2 over SSH1, as it offers better security, performance, and functionality. If you have any systems that still use SSH1, you should upgrade them to SSH2 as soon as possible.
Comparative Table: SSH1 vs SSH2
The major differences between SSH1 and SSH2 fall into two main categories: technical and licensing. Here is a table comparing the two protocols:
| Feature | SSH1 | SSH2 |
|---|---|---|
| Encryption and Authentication Algorithms | Uses four encryption algorithms, two of which are insecure | Uses different encryption and authentication algorithms, including SFTP |
| Algorithm Choice and Negotiation | Offers algorithm negotiation for bulk encryption cipher, but other algorithms are hardcoded and inflexible | Improves upon this by making other algorithms negotiable between client and server, such as host key, message authentication, hash function, session key exchange, and data compression |
| Licensing | Free to use, but may conflict with intellectual property rights | Designed to avoid intellectual property claims and conflicts |
| Compatibility | Not compatible with SSH2 | Supports backward compatibility with SSH1 |
SSH2 is the recommended and preferred version of SSH, as it offers better security, performance, and functionality than SSH1. SSH1 is outdated and vulnerable, and should be avoided at all costs. If you have any systems that still use SSH1, you should upgrade them to SSH2 as soon as possible.