How is authenticity of a given evidence determined? I was reading this question on security SE. The title of the question is: "What are legal/ethical concerns to bear in mind, when hacking websites with open invitations?" This answer suggests to "log everything you do just in case something bad happens and you need to prove it wasn't you, or wasn't deliberate!" I thought "How would that even help? How hard can it be to forge a log file? Or better yet, how hard can it be to log only the "legal" actions you do and exclude the illegal ones, and present this log file as evidence?" Similarly this question. In the question, OP states that his boss asks him to forge a log file in order to win a dispute. The answers clearly suggests not to do it. They also suggest to get the requested action written and to make sure a copy of this document is available outside the work (just in case the boss tries to destroy the evidence in case of a legal action). Again, assume that this incident is indeed carried to court and boss claims he did not request such thing. The employee claims the boss requested such thing and presents his copy of the written request as an evidence. The boss claims that this was forged by the employee. What is going to happen? Who is the judge going to believe? Or yet a simpler example. Say Party 1 has some witnesses. Party 2 claims what these witnesses say is not correct and presents some kind of counter evidence. What is going to happen? In the end, what determines which party the judge is going to believe?
In law there are two different concepts: admissibility of evidence and the weight of that evidence. Your question concerns both. I will begin by discussing a little bit about what both these two terms mean. Admissibility means that this evidence may go before the trier of fact. Typically the trier of fact is the jury, however, if both parties have waived their rights to jury trials (particularly the defendant) the judge is the trier of fact as well as the law. When documents or testimony by witnesses is admissible, the trier of fact can consider it in reaching a decision. Weight of evidence is a different concept. The weight of evidence is what someone believes. For example if two witnesses who were bystanders testify that the light was red, but the defendant testifies that the light was green, most people would believe the bystanders. However, in this case the evidence by the defendant that the light was green is admissible, but the trier of fact may not afford it much weight. Now let's consider these logs. In the United States all statements made out of court, whether verbal or written, are considered hearsay (with some exceptions, a couple will be discussed later). Hearsay is generally inadmissible; however, there are many hearsay exceptions. One exception is a record of a regularly conducted activity. The requirements are (summarized, you may refer to the federal rules of evidence 803-6.) for the full text): (A) the record was made at the time of the event by someone who knew about what happened (B) the record was kept in the course of this regularly conducted activity (C) making the record was a regular practice of that activity (D) all these conditions are shown by the testimony of the custodian or another qualified witness (E) neither the opponent does not show that the source of information nor or the method or circumstances of preparation indicate a lack of trustworthiness. Now if these logs fit these requirements you can most likely use them in court. If they don't you probably will not be able to use to in court, unless one of the following applies: 1.) you are being sued by someone (or you are suing them) who made the logs and you are offering the logs against them (this is referred to in legal settings as party-opponent statements) OR 2.) the other party has offered evidence that you are lying and you are offering this logs to show you are telling the truth. Most likely the only admissible evidence would be the testimony of the employee and the employer. This leads to a he said she said scenario and the legal results will be highly ambiguous. The credibility of both witnesses will be likely assessed by the trier of fact and the trier will consider who has a higher incentive to lie. If there are more witnesses saying one thing versus another, it is likely they will be believed unless there is a reason all of them are lying. Although this is not legal advice, my suggestion for an employee in such a situation is to gather evidence that an employer asked you to commit a crime as part of your job. Print out emails, get written requests from the employer, and have witnesses present at the time of the request. Then the employee should refuse to perform the act. If as a result the employee is fired, one can sue. All these statements of the employer can be admitted as party-opponent statements. Additionally I suggest that you advocate for your company to adopt policies which require record keeping, which will satisfy the hearsay exception given above.
You are confusing two different but related concepts: proof and evidence. A claim is proved when a court decides that the world is the way the claim says. In reaching that decision, the court will consider the evidence presented for and against the claim. A fax transmittal is strong evidence that a given number of pages were sent and successfully received: it is likely that a court would consider the evidence strong enough to prove that claim. It is not evidence that they were received by a particular person, or read or understood: this may or may not have legal ramifications. It is also not evidence that what was sent/received is what the sender says was sent/received. For example, if the sender put the pages in the fax back-to-front, the fax would transmit those blank pages and receive acknowledgment that they had been received.
It's true that you can't prove what was in the envelope. But assuming this ends in small claims court or some sort of collections action lets play out how it works. The company is going to claim that they never got notice of cancellation. They will plead ignorance so they won't have any evidence of what you didn't send. That's obvious, but more on this later. You are going to have a trove of evidence. The emails you sent, the webforms you filled out, the voicemails you left. And finally, the letters that you sent. Let's think about the weight of evidence! At the very least you can ask them, if they claim they didn't get a cancellation from you, what did they get in that certified envelope from you? They'll need to produce whatever was in the envelope. Unless they claim that it was empty. At this point the judge will see exactly what is going on and you won't need to prove what was in the envelope. Legally, the way this works is covered by Rule 901. (a) In General. To satisfy the requirement of authenticating or identifying an item of evidence, the proponent must produce evidence sufficient to support a finding that the item is what the proponent claims it is. (b) Examples. The following are examples only — not a complete list — of evidence that satisfies the requirement (1) Testimony of a Witness with Knowledge. Testimony that an item is what it is claimed to be. It's that last piece that matters here. You will take the stand and testify that the letter you brought to court is a true copy of the letter in the envelope.
If you state, to a third person, that Joe has performed a criminal act then that is defamation and you can be sued. Unless it is true. However, if you are relying on the truth as a defence you will need to provide evidence that it is. At the moment you lack: a criminal conviction of Joe any physical evidence against Joe any personal knowledge that Joe has committed these acts. All you have, is second hand rumours that this has happened to 5 women, some of whom have reported it to you in person. This is called hearsay and it is not evidence. It may be true, it probably is true - you can't prove it's true and in court, that's all that matters. If you were sued your only possible defence is to call these women to give the evidence they are unwilling to give - are you willing to betray their confidence to that extent?
A contract need not be written to be valid and enforceable. However, if there is no written contract, then in a dispute the burden of proving (via a preponderance of evidence) a contractual obligation falls on the party asserting it. In the scenario you describe it sounds like that would be impossible for the processing company.
Whether they are admissible as evidence is up to the trier of law The “trier of law” (judge) decides what evidence is admissible according to the rules of evidence. Documents of most kinds are not admissible on their own (exceptions include “business” documents like invoices and receipts). To be admissible, someone (presumably you) has to testify as to what they are, how they were created and maintained and why they are relevant before the judge will decide if they will be accepted as evidence. Whether they prove anything is up to the trier of fact Evidence is not proof The “trier of fact” (jury in a jury trial, judge in a bench trial) decides what weight to give to any and all evidence presented. They may accept the testimony about the documents or they may reject it. If presented with conflicting testimony they have to decide which they prefer. Judges have to give reasons for their decisions which can be appealed. Juries don’t. Files that are readily changeable are likely to be given less weight than files which have a verifiable audit trail. For example, if you kept your .docx files in a GitHub repository they will be stronger evidence than those kept on a local hard drive.
The issues you describe have existed with signatures from the beginning of their use. There exists a tradeoff between ease of use and reliability, both of forgery and of people falsely claiming forgery. Originally, the closest thing to a signature was the use of seals and signet rings. While relatively hard to forge, it only showed that the possessor of the object agreed. Signatures, especially in cursive font, were developed later. They were in some ways easier to forge(you didn't need to get access to a physical device), but more difficult in others(the seal symbols tended to be used on everything and various improvements in technology had been made), and harder to falsely claim forgery(because most people can't alter their handwriting well). You were affixing your name to the document, indicating that you agreed. Often, the signatures were required to backed up with the signatures of other people as witnesses. They didn't have to agree to the document, they just had to agree to testify that you signed of your own free will. Because witnesses, especially trustworthy and independent witnesses, are hard to come by, some places have dropped that requirement, such as checks and signing a aper receipt when using a credit card. But for some important documents, certain jurisdictions still require witnesses, including large transactions (a document relating to a car insurance payout I recently had required a witness to confirm my signature) and marriages. However, with electronic media, the point of a signature is more to indicate deliberate acceptance of terms, with verification of an individual being left to other processes (e.g. IP address, MAC address, linkage to a specific email account, etc.), so forgery is less of an issue. I have also seen "signatures" amount to checkboxes and "I agree" buttons. Generally, the higher the stakes and "more legal" the agreement, the more likely to these have been the "typed signatures" that you describe, but this seems to be decreasing in frequency, suggesting that its purpose was to stop gap a hole in legal acceptance by judges/courts/laws with regards to electronic communications. Addendum: It should also note that the replacement of seals by signatures is not universal; for instance in Japan, seals are still used over signatures in the majority of cases.
Just like every other contested assertion They hear the testimony (evidence-in-chief, cross-examination, redirect), look at whatever physical evidence and submissions on the law that the party wishes to make. The other party will do the same. They weigh the evidence including such vital considerations as to whether they think one party or the other or both are full of shit and, if the evidence is such that the party has proved their assertion on the balance of probabilities, it is now a fact which bears on the judgement.