Use CPrivKey typedef for keydata in CKey

[AmirAbrams]

Seems like the keydata member variable in CKey should be a CPrivKey type. Is there a reason it was re-declared as a std::vector<unsigned char, secure_allocator<unsigned char> > and the CPrivKey typedef isn't used?

[promag]

When keydata was added the typedef was already there, see f4d1fc2#diff-dd01571c9de4333a6af0b54c71ae2ad8R32.

ACK 21f69f6.

[sipa]

CPrivKey was intended to be a type for DER-encoded private keys, which the contents of CKey is not.

If you're changing CPrivKey to be "generic secure storage of bytes", please update the comment above CPrivKey as well.

[AmirAbrams]

@sipa, I updated the comment to //! A generic storage of bytes using secure allocators
Is that what you had in mind? Thanks

On a related subject, in some cases, it might be better to use an alias instead of a typedef because they can be used with templates: Stack Overflow typedef and using in C++11
typedef std::vector<unsigned char, secure_allocator<unsigned char> > CPrivKey;

to

using CPrivKey = std::vector<unsigned char, secure_allocator<unsigned char> >;

[laanwj]

Is that what you had in mind? Thanks

He means the comment above CPrivKey here: https://github.com/bitcoin/bitcoin/blob/master/src/key.h#L30
This specifically mentions a size and encoding, which is no longer true if you use it as a generic typedef.

[laanwj]

Closing this for now, feel free to ping me if you want to pick this up again.