HelloTech has a series of documents they want potential technicians to sign. These are delivered by an email containing a link to their documents in the HelloSign document-signing service. Clicking this link sends the potential technician to a document they can sign, but there is no authentication step to verify that the person that's signing the document is who they say they are.

Since anyone could intercept the unauthenticated email link in transit and impersonate the signer, how can HelloSign claim that such a signature is legally valid?

1 Answer 1


anyone could intercept the unauthenticated email link in transit and impersonate the signer


If they sent a paper copy, anyone could intercept it in transit and impersonate the signer. In both cases, this would be fraud and to quote from my answer to How to prove the genuinity/nongenuinity of a signature?

Fraud would have to be proved: it would not be sufficient to say "I did not sign that"; the person would need to demonstrate that a fraud has been perpetrated.

A party to a contract is entitled to rely prima facie on the validity of the signature. A person would have to provide evidence that it was not their signature or had been affixed without their knowledge or consent.

A court would look at the entire circumstances surrounding such a claim; if a person had, up until the dispute, acted as though they had signed the document then a court would probably not countenance an argument that they hadn't.

It is always possible to construct contrived circumstances where this or that could happen but, in reality, they are extremely rare. Unless you are dealing with a con-artist, you can trust the signature; if you are dealing with a con-artist, you have bigger problems.

It is irrelevant whether the signature is in ink or in bits, the same principles apply.

Of course, it is entirely possible, even likely, that the link sends a lot more information back to the HelloSign service than you think it does. Information that can both validate signatures and be stored as evidence.

  • Email vs. physical mail in transit is a false comparison. There are legal ramifications for tampering with physical mail, but email by definition is clear text and available for viewing by anyone. Commented Nov 29, 2016 at 22:32
  • @Bill_Stewart I didn't mention the transit of the physical copy was by mail - hand delivery our courier are both options. Anyway, how the interception happens is beside the point.
    – Dale M
    Commented Nov 29, 2016 at 23:29
  • I think I must not be explaining properly. A responsible party obtaining a signature will (or should) take reasonable means to ensure the signature is valid: Examples would be a courier requesting an ID, sealed mail, or web site authentication. Unauthenticated email has no means of proving the signer is actually the signer. It's even worse than that, because email by definition is clear-text, which means anyone could sign for anyone else, and there is no way to tell. Commented Nov 29, 2016 at 23:57
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    @Bill_Stewart You're assuming that wet-ink signatures are somehow supposed to be unforgeable proof of identity. They're not. Courts are well aware that signatures can be faked, but they also know that you don't need to look at the signature in isolation. You can call witnesses (including the person who supposedly signed) to testify under oath (i.e. lying risks felony perjury charges), you can look at how people acted, you can do a lot of things. And in the end, you look at what is more likely, not at whether something is 100% certain.
    – cpast
    Commented Nov 30, 2016 at 1:18
  • Sure, but that's not really relevant to the question. I'm afraid I have asked a bit too technical of a question here. Of course things can be faked; the issue is that with an unauthenticated email it is really, really easy to fake and that's what I am drawing attention to here. Commented Nov 30, 2016 at 1:27

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