Use CPrivKey typedef for keydata in CKey #11482

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?

When keydata was added the typedef was already there, see https://github.com/bitcoin/bitcoin/commit/f4d1fc259b5a62580d952c180b1189ccaa6af1bc#diff-dd01571c9de4333a6af0b54c71ae2ad8R32.

ACK 21f69f6.

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.

@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> >;

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.

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