Advantages of 64-bit CPU smartphone Advantages of having a 64-bit CPU vs 32-Bit CPU smartphone
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  3. Complex Encryption. Improved Security: 64-Bit can process incredibly large numbers allowing you to better encrypt data against unauthorized access.


source: http://www.amongtech.com/what-is-the-advantage-of-having-a-64-bit-smartphone/

Is the above statement correct, in particular with regards to the term “complex encryption”? I mean, how is the complexity increased with 64 bits? Is that related to the increase of the key size?
In terms of marketing hype, that statement rates about a 9 in a scale from 0-10.

The reason is that we don't choose the encryption algorithm based on how many bits the CPU can handle at once.  Instead, we choose a secure algorithm, and then implement it using the resources that the CPU provides us.  There aren't any algorithms we cannot implement on a 32 bit CPU; hence a 64 bit CPU does not allow us to use new ones.

Now, there is a tiny kernel of truth there (and so doesn't rate a perfect 10 on the scale); sometimes a 64 bit CPU allows us to implement an algorithm more efficiently than a 32 bit CPU.  However, the delta is usually not large enough to influence an 'can-we-encrypt' decision.