# I am both lock and key - who am I?

Enter! Small or large, as the case may be
I'll assist you - it's easy! - I'm both lock and key

Who am I?

You are

The CAPS LOCK key

Enter! Small or large, as the case may be

ENTER is another key on the keyboard. CAPS LOCK is used to toggle case between lower and upper, or small and large.

Author's note: in addition, the injunction "Enter! Small or large, as the case may be" can be read as an invitation to enter text into the computer by typing it in, in the appropriate case (lower or upper).

I'll assist you - it's easy!

CAPS LOCK makes it easier to type a string of capital letters, rather than SHIFT.

I'm both lock and key

Lock is in the name, and a key is what you are.

• Now that you're the winner, can you expand your answer a bit? After all, with great power comes great responsibility. – user17947 Mar 24 '16 at 18:02
• Thanks! I took the liberty of editing your answer to add another small clarification note. – user17947 Mar 24 '16 at 18:15
• Doesn't "assist" me because I normally pop it off with a ruler on my keyboards to avoid my clumsy fingers hitting it :-) – Alan Macdonald Mar 25 '16 at 16:35

You are

the CAPS LOCK key on a keyboard

Enter! Small or large, as the case may be

controls character case (small or large)

I'll assist you - it's easy! - I'm both lock and key

caps LOCK KEY

• Darn! Missed it by 4 seconds. That's what I get for being wordy. – Solocutor Mar 24 '16 at 17:12
• hahaha. I knew it would be fast, so I raced to the character limit, and then edited a few more words in. Worth it! – Matt Mar 24 '16 at 17:16
• Nice work to both of you, and sorry I can't select both. It's a cutthroat business, puzzling... – user17947 Mar 24 '16 at 17:56

I know this has already been answered correctly, but I thought I would add what sprung to mind when I read the title, maybe someone will find it interesting.

You are

A cipher key

Enter! Small or large, as the case may be

A key can be small or large, depending on the circumstances. Eg. a user's password to decrypt their hard drive, or an SSH keypair used to encrypt and decrypt network transmissions which is comparatively quite large.

I'll assist you - it's easy! - I'm both lock and key

The key(s) can be used to both encrypt and decrypt the information.

• This is what I thought of as well, especially when seeing only the title in the hot network questions list. – Amani Kilumanga Mar 25 '16 at 1:55
• "small or large": Cryptographic keys can be anywhere from 40-bit (export-controlled) to 128-bit (symmetric) to 2048-bit (recommended RSA) – Nayuki Mar 26 '16 at 3:37
• As soon as I saw it in the HNQ, I thought "a symmetric encryption key". – wizzwizz4 Mar 27 '16 at 10:10

As a perhaps tongue-in-cheek alternative:

Tom Hiddleston

Enter!

Tom plays Loki, and who can make an entrance to rival Loki's? Nobody! So much so that there is, in fact, a LEGO/Marvel computer game called A Loki Entrance. Because it's a pun, you see, on "low-key".

Small or large, as the case may be

Loki is a frost giant. That's fairly large. He can also become human sized.

I'll assist you - it's easy!

He's a helpful guy, whether you are a big famous reporter, unicef, or just a kid

I'm both lock and key

Loki contains "Lok" and "ki".

Who am I?

The question requires it be a who, not a what, and therefore cannot be the caps lock key! :D

• Like this one better 😁 – Chilion Mar 26 '16 at 7:56

You are

Yog-Sothoth

Because,

Yog-Sothoth knows the gate. Yog-Sothoth is the gate. Yog-Sothoth is the key and guardian of the gate. Past, present, future, all are one in Yog-Sothoth. He knows where the Old Ones broke through of old, and where They shall break through again. He knows where They have trod earth's fields, and where They still tread them, and why no one can behold Them as They tread.
—H. P. Lovecraft, "The Dunwich Horror"

You are

Those blueprints from Contact. Encoded within them were the instructions to read them.