“Much like real life signatures, digital signatures can vary slightly and yet still be valid.”
This line might needlessly spook some people regarding the authenticity of bitcoin transactions. I think a easy to intuit, real-world example would be, the inverse image (i.e. the negative from a copy machine or film photo) of a physical signature still proves it’s valid. What’s going on in the background is that the piece of crypto that handles signatures uses a mathematical curve that’s symmetrical on one axis (Metaphor: It doesn’t matter if the signature is black ink on white paper or white ink on black paper) and therefore you can invert the value and flip the signature. Resulting in a signature that’s still valid/authentic but looks different. Bitcoin version 0.11 enforced one version of how this signature could exist (Black ink on white paper). https://en.bitcoin.it/wiki/Transaction_Malleability
https://github.com/bitcoin/bips/blob/master/bip-0066.mediawiki
