How Safe Is a Digitally Signed PDF Document?

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How safe is a digitally signed PDF document?

The math that makes public key encryption work also makes digital signatures secure. Short version, using random numbers, you make a pair of related keys, a public key (pk) and a private (secret) key (sk). You are the only person with secret key. There is a set of mathematical formulas that encrypt and decrypt. To send someone an encrypted message, yout take their public key and encrypt the message with an ENCRYPTING algorithm. ENCRYPT(MESSAGE, pk) → SECRET_MESSAGE. Unless you know the private key, you cannot decrypt the message. To read the message, use the DECRYPTING algorithm, DECRYPT(SECRET_MESSAGE, sk) → MESSAGE. Now, with this in mind, suppose I want to prove a message is from me. I can do a clever trick. I can DECRYPT (!) a message with my private key to make an enciphered public message. DECRYPT (MESSAGE, sk) → PUBLIC_MESSAGE Anyone with my public key can read this message by “encrypting” it with my public key. ENCRYPT (PUBLIC_MESSAGE, pk) → MESSAGE Now, since only my public key will produce the message when running the encryption algorithm, you can be assured it was from me! The problem here is that nobody can read the message without using the key, despite the fact that it is a public message. So, instead of enciphering the entire message, we do a trick. We run a Cryptographic hash function (sometimes called a digest) on the message to produce a fixed-length binary value that represents the message. In general, it is VERY difficult, nearly impossible, to produce two messages that result in the same hash value. It is impossible to have two intelligible messages with the same hash. The probability is so low that a message that produces an identical hash is considered identical. Now, we can produce the PUBLIC_MESSAGE and it’s digest, PUBLIC_MESSAGE_HASH. The signature gets created by running DECRYPT(PUBLIC_MESSAGE_HASH, sk) → SIGNATURE. The enciphered signature is readily exposed along with the message. Now, anyone can run ENCRYPT (SIGNATURE, pk) → PUBLIC_MESSAGE_HASH. Given the PUBLIC_MESSAGE, SIGNATURE, and the public key (pk), the receiver can calculate the digest of PUBLIC_MESSAGE and compare it to the derived PUBLIC_MESSAGE_HASH extracted from the signature. If t match, t know for sure that the message is authentic, untampered, and sent by the holder of the secret key (sk) associated with the public key (pk) of the purported sender.

PDF documents can be cumbersome to edit, especially when you need to change the text or sign a form. However, working with PDFs is made beyond-easy and highly productive with the right tool.

How to Sign PDF Online with minimal effort on your side:

  1. Add the document you want to edit — choose any convenient way to do so.
  2. Type, replace, or delete text anywhere in your PDF.
  3. Improve your text’s clarity by annotating it: add sticky notes, comments, or text blogs; black out or highlight the text.
  4. Add fillable fields (name, date, signature, formulas, etc.) to collect information or signatures from the receiving parties quickly.
  5. Assign each field to a specific recipient and set the filling order as you Sign PDF Online.
  6. Prevent third parties from claiming credit for your document by adding a watermark.
  7. Password-protect your PDF with sensitive information.
  8. Notarize documents online or submit your reports.
  9. Save the completed document in any format you need.

The solution offers a vast space for experiments. Give it a try now and see for yourself. Sign PDF Online with ease and take advantage of the whole suite of editing features.

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Sign PDF Online: All You Need to Know

That is what I would recommend for all the businesses that still use paper signatures in today's world. 3.  E-signing in the future: What will this technology look like in the future? The number of businesses that have become aware of the security of using encryption and digital signatures for business purposes, but fail to do it consistently due to a shortage of manpower and the shortage of space, is increasing. If you are a business that is still using office paper signatures and/or manual signing for sensitive tasks, you can rely on the fact that things will stay the same. A big technology shift and the use of advanced technology will transform the digital signature technology.   Nowadays, a business needs its own ‬system to comply with new standards.   Therefore, if there are still business owners who have been following the past and blindly relying on paper signatures, I would.