Can a document be digitally signed multiple times, successively by different users?

The question is, if a document that is collaboratively edited, one user per time, could be digitally signed by every editor before it is passed to the next editor. And if yes, could the final receiver use the public keys of e… Continue reading Can a document be digitally signed multiple times, successively by different users?

How to sign a text in a way, so it can not be altered or split in parts unacknowledged

Given, I want to create a document (text-only for the sake of this question) and give it to someone I do not trust. I am not allowed to publish it myself. It’s probably not going to be published (publicly) anyway.

But in ca… Continue reading How to sign a text in a way, so it can not be altered or split in parts unacknowledged

Coda’s programmable document editor comes out of beta, launches iOS app

Coda, which is coming out of its limited beta today, wants to reinvent how you think about documents and spreadsheets. That’s about as tough a challenge as you can set yourself, given how ingrained tools like Word, Excel and their equivalents from the likes of Google, Zoho and others are. Coda’s secret weapon is that […] Continue reading Coda’s programmable document editor comes out of beta, launches iOS app

Is it possible to verify that a signature was made prior to the content of the document it is found on?

In What to do after I signed a blank sheet of paper given to me by my manager?, a distressed individual (B) has signed a blank piece of paper and given it to an adversary (A).

A has openly stated to B that her intention is … Continue reading Is it possible to verify that a signature was made prior to the content of the document it is found on?