key size
The size in bits of the public key. Generally, the larger the key size, the more resistant the private key is to cryptanalysis (subversion of the cryptosystem).

You should choose the largest key size possible. Larger keys are harder to break and provide a more secure environment for your application, but take longer to process.

The following table will help you determine the restrictions on key size depending on your intended use:

Algorithm Key Size Key Usage Type
RSA 4096, 2048, 1024, 768, 512 Bits Key Encipherment Digital Signature Data Encipherment Unspecified, Encryption, Signature, Custom, TLS
ECDSA 384, 256, 521 Bits Key Encipherment Digital Signature Data Encipherment Unspecified, Encryption, Signature, Custom, TLS