c. 2600 BCE Sealings secure goods and records Administrative sealings become routine in early cities, linking authentication to storage, trade, and bureaucracy. c. 1600 BCE Aegean stamp seals flourish Small carved seals spread through the eastern Mediterranean as portable markers of personal and official identity. 221 BCE Imperial China standardizes seal authority The Qin unification strengthens the use of official seals in government and administration. c. 500 BCE Roman signet rings popularize personal sealing In Roman practice, the signet ring becomes a widely recognized tool for validating correspondence and documents. c. 500 BCE Early Islamic administration adopts seals and written validation Expanding Islamic states combine documentary writing with seals to secure orders, taxes, and contracts. c. 500 BCE European chancery seals gain political weight Royal and ecclesiastical chanceries in medieval Europe rely on seals for formal authentication. c. 500 BCE Medieval great seals spread Rulers, bishops, and nobles adopt distinct seals that carry legal and symbolic authority. c. 500 BCE Notarial signa develop alongside seals Southern European notaries use written signs and subscriptions, helping handwritten validation gain prestige. 1279 Statute of merchants expands documentary formality Commercial Europe increasingly depends on signed or sealed instruments to structure debt and contract enforcement. c. 1450 Paper growth broadens personal document use Cheaper paper and expanding literacy gradually make written subscription more common in business and private life. 1677 Statute of Frauds elevates signed writing English law gives new force to written and signed agreements in major transactions. c. 500 BCE Cursive signature becomes a social norm Increasing literacy and standardized schooling make the handwritten signature a routine mark of personal responsibility. 1861 Signature cards support modern banking Banks increasingly use specimen signatures to verify account holders and payment instructions. 1888 Typewriters complicate personal authorship Typed documents spread in offices, making handwritten signatures more important as proof of assent. 1976 Public-key cryptography reframes the signature Whitfield Diffie and Martin Hellman popularize methods that make digital signatures conceptually practical. 1991 First U.S. Digital Signature Standard appears NIST issues FIPS 186, giving federal systems a formal digital-signature standard. June 30, 2000 E-SIGN Act recognizes electronic signatures The United States enacts a federal law granting electronic signatures legal effect in commerce. July 1, 2016 eIDAS framework takes effect across the EU The European Union's eIDAS system strengthens cross-border rules for electronic identification and signatures. February 3, 2023 NIST updates the digital signature standard FIPS 186-5 refreshes the modern cryptographic rules behind digital signatures.