# Detect tampered and deepfake Promissory Note > A promissory note is the borrower's signed promise to repay, and it is the document a lender or note buyer actually enforces. It can be one paragraph on plain paper, with no letterhead and no security print, which makes alteration and backdating easy. The check is whether the terms, the signature, and any endorsements belong together, and whether the text of the terms was set at the same moment as the rest of the page. **Canonical URL:** https://tampercheck.ai/documents-support/promissory_note **API document class:** `promissory_note` --- ## What a genuine promissory note contains A promissory note names the maker, who promises to pay, and the payee, who receives. It states the principal, the interest rate, how and when payments are due, the maturity date, late-fee and default terms, and the governing law. The maker signs and dates it, often with a witness or notary. If the note is sold, endorsements appear on the note or on an attached allonge. The terms should be consistent: amounts written in words agree with figures, the maturity date follows from the payment schedule, and the parties' names match those on any mortgage or deed of trust that secures the debt. Endorsements should run in an unbroken chain from the original payee to the present holder. A witness or notary block should show a real acknowledgement, not an outline. ## How promissory note forgeries are made ### Principal and rate alteration Numbers are changed after signing to raise the debt or the interest. Words and figures stop agreeing, and the edited digits differ in ink or rendering from the printed line. ### Backdating The note's date is moved to predate a bankruptcy, a divorce, or a limitations period. The date is a small text region whose rendering seldom matches the surrounding typeface. ### Signature lifting A maker's signature is copied from another document onto a note they never signed. Identical stroke geometry across two documents from different dates is a finding. ### Endorsement insertion A fake transfer is added to establish who holds the note. The endorsement page has different paper texture and alignment, or the chain skips a holder. ## What TamperCheck checks on a promissory note TamperCheck runs 200+ forensic checks across three layers and returns a risk score from 0 to 100 with plain-English findings tied to specific regions of the document. These three carry the most weight on this document class. ### Embossed seal analysis A physically embossed seal deforms the paper it sits on. A seal that was scanned and reprinted is flat, and the two separate cleanly under analysis even when they are hard to tell apart by eye. ### Arithmetic reconciliation Stated totals are recomputed from their components, and running or cumulative figures are checked for continuity across periods. A single edited value breaks the chain even when the page still looks right. ### Signature forgery analysis Signature regions are assessed for ink consistency and for how the stroke sits on the page, which distinguishes a genuine pen stroke from a pasted image of one. ### And many more checks The three above are the layers that carry the most weight on a promissory note. Every upload runs the full suite of 200+ checks regardless of document class, spanning file structure and metadata, pixel-level forensics, font and text rendering, optical and print characteristics, provenance signals, AI-generation signatures, and many more checks. ## Who verifies a promissory note, and why Lenders, note buyers, attorneys, and courts handling debt disputes. In each case the document is being used to unlock money, access, or a legal status, which is exactly what makes it worth forging. ## How to verify a promissory note in 4 steps 1. **Check the fields against each other.** Read principal and interest terms, maturity date, and signature together rather than one at a time. Forgers typically change one value and leave the rest of the document describing the original. 2. **Inspect the file metadata.** Open the document properties and look at the producer, creation date, and modification date. A document produced by a consumer PDF editor, or created long after the date printed on its face, is worth a closer look. 3. **Ask for a second document.** Request a corroborating document from the same issuer or an adjacent period. Forgery effort concentrates on one file, so inconsistencies surface as soon as there are two to compare. 4. **Run a forensic check.** Manual review catches obvious edits but not field-level pixel manipulation or synthetic generation. TamperCheck runs 200+ forensic checks on a promissory note and returns a risk score from 0 to 100 in about a minute, at $0.50 per document. ## Frequently asked questions ### How can I tell if a promissory note was forged? Look for figures that disagree with the written amounts, a signature identical to one on another document, a date out of sequence with related papers, and an endorsement chain with gaps. Forensic analysis of the file can also show edited terms and pasted signatures. ### What is altered on a promissory note? Principal, interest rate, maturity date, and the date of the note itself. In disputes over who owns the debt, the endorsements are altered or added instead. The terms are short, so each change is a small region on the page. ### Does a promissory note need to be notarised? Not usually to be valid. Notarisation or witnessing helps prove who signed and when, and some lenders require it. A missing notary block is not evidence of forgery, but a block that appears pasted in deserves a closer look. ### What is the difference between a promissory note and a mortgage? The note is the promise to repay. The mortgage or deed of trust is the separate security instrument giving the lender a claim on the property. A secured loan involves both, and their parties and amounts must agree. ## Related document types - Loan Statement: https://tampercheck.ai/documents-support/loan_statement - Loan Sanction Letter: https://tampercheck.ai/documents-support/loan_sanction_letter - Amortization Schedule: https://tampercheck.ai/documents-support/amortization_schedule - Loan Payoff Statement: https://tampercheck.ai/documents-support/loan_payoff_statement - Loan Closure Certificate: https://tampercheck.ai/documents-support/loan_closure_certificate - Closing Disclosure: https://tampercheck.ai/documents-support/closing_disclosure --- Try TamperCheck now: https://tampercheck.ai/dashboard · Docs: https://tampercheck.ai/docs · Pricing: https://tampercheck.ai/pricing