There is no magic number needed to make a device "cryptographically secure". It depends entirely on the operations being performed. In general if you generatin

There is no magic number needed to make a device "cryptographically secure". It depends entirely on the operations being performed. In general if you generating Keys, the DRBG or PRNG used in key generation needs to be seeded with entropy equal to the security strength of the key. For example: If you are generating 128 bit AES keys, the DRBG needs to be seeded with at least 128 bits of entropy. If you generating 2048 bit RSA keys you'll need 112 bits of entropy.