RSA is one of the most used methods for encryption and digital signatures. It is built on a pair of keys: one public and one secret. HCL Notes uses RSA in every Notes ID.
RSA is a method for encryption and digital signatures. The name comes from the three researchers who invented it in 1977: Rivest, Shamir and Adleman. RSA is still one of the most used methods in the world. It is used on the internet, in mail and in HCL Notes.
Public and secret key
RSA uses a pair of keys. Everyone may see the public key. You keep the secret key to yourself.
- Encryption: If someone wants to send you a secret message, they lock it with your public key. Only your secret key can unlock it again.
- Signature: When you sign something with your secret key, anyone can check it with your public key. Then they know it came from you and has not been changed.
Why is RSA safe?
RSA is built on a simple fact. It is easy to multiply two large prime numbers. But it is very hard to find the two numbers again when you only have the result. With long keys it takes a normal computer thousands of years. ECC is a newer method built on another kind of maths problem. It has the same strengths and weaknesses.
RSA in HCL Notes
Every Notes ID holds a pair of RSA keys. They are used when you log in to the server, when you sign mail and documents, and when mail and fields are encrypted. Old ID files may have short keys. They should be changed to longer keys. Domino can do this for all users in one process.
The threat from quantum computers
A large quantum computer can find the prime numbers very fast. Then it can work out the secret key from the public key. This applies to both RSA and ECC, no matter how long the keys are. That is why NIST will phase out the weakest RSA keys after 2030 and stop RSA completely in 2035. The replacement is quantum safe encryption. Read also about the threat called harvest now, decrypt later.