CODEWITHSUNDEEP
javascriptcryptographyprivate-key
Adam
Adam

Reputation: 3518

How to sign data with key that has short signature in javascript

How can I sign data having a private key in javascript?

I found a really good example: example. In the example though the signature is really long. Is it possible to have it short? For example 6 characters?

Having the signature short is a bonus really. How can I do it in javascript in a first place?

Thank you!

Upvotes: 0

Views: 370

Answers (1)

Maarten Bodewes
Maarten Bodewes

Reputation: 94038

The page you point to already shows an example in JavaScript.

You cannot have an asymmetric signature consisting of 6 characters though because that's too small to be cryptographically be secure. For 6 characters the chance of somebody simply guessing the signature would be too large.

The best you can do with existing software is probably a 64 byte ECDSA signature for a 256 bit prime curve such as P256 / secp256r1 - as standardized by NIST. There are some ways of bringing that down to 32 bytes, but that's about it.

If your problem allows for symmetric encryption then you could use a 6 byte MAC rather than a signature. Six full bytes are too short for a MAC too, but in certain situations it may be good enough.

Upvotes: 1

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