# SSH AES and ECC Questions

## dman777

I'm a little confused on SSH configuration for security:

1)For using keys, how is it RSA is used with AES? I thought AES encryption would be a replacement for RSA.

2) For using passwords to login, asymmetric encryption has to be done. So ECC would be the best, right?

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## manaka

RSA is asymmetric, AES is symmetric. One is not the replacement of the other. They are used for different tasks.

ECDSA is newer than RSA. It's cooler. But both are considered secure if used with a sufficient key length.

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## John R. Graham

One of the somewhat misunderstood facts about asymmetric cryptography is that it's way too inefficient to use for bulk encryption. In all modern cryptosystems, asymmetric cryptography (e.g., RSA, ECC) is used to securely exchange keys for a symmetric cipher (e.g., AES, 3DES), which then handles the bulk of the encryption.

- John

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