Digital Signatures
Digital signatures usam asymmetric cryptography para autenticar o remetente de uma mensagem ou o signatário de um documento, garantindo integridade e non-repudiation.
Digital signatures são baseadas em asymmetric cryptography, usando um key pair: uma private key para signing e uma public key para verification. O signatário faz o hash da mensagem, assina o hash com a private key e anexa a signature à mensagem. O destinatário verifica decifrando a signature com a public key do remetente e comparando com um fresh hash da mensagem. Algoritmos comuns incluem RSA, DSA e ECDSA; a prática moderna também usa EdDSA (e.g., Ed25519). A segurança depende da private key permanecer confidencial e da hash [function](/pt/terms/hash-function) resistir a collisions. Em PKI deployments, public keys são vinculadas a identidades via certificates emitidos por trusted authorities. Vulnerabilidades potenciais incluem weak keys, compromised keys, hash-function weaknesses, side-channel leakage e implementation flaws. Best practices incluem robust key management, certificate lifecycle handling e a seleção de algoritmos com adequate security margins.
graph LR
Center["Digital Signatures"]:::main
Rel_digital_asset_security["digital-asset-security"]:::related -.-> Center
click Rel_digital_asset_security "/terms/digital-asset-security"
Rel_digital_forensics["digital-forensics"]:::related -.-> Center
click Rel_digital_forensics "/terms/digital-forensics"
Rel_digital_certificate_management["digital-certificate-management"]:::related -.-> Center
click Rel_digital_certificate_management "/terms/digital-certificate-management"
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❓ Perguntas frequentes
What is the purpose of a digital signature?
To authenticate the signer, ensure message integrity, and provide non-repudiation.
Which algorithms are commonly used for signing?
RSA, DSA, ECDSA; EdDSA (e.g., Ed25519) is widely adopted in modern systems.
How is a digital signature created?
Hash the message and sign the hash with the private key; attach the signature.
How is a digital signature verified?
Decrypt the signature with the public key and compare to a hash of the message.
What are common vulnerabilities?
Weak private keys, compromised keys, weak hash functions, side-channel attacks, and faulty implementations.
What is PKI and why is it important?
PKI binds public keys to identities through certificates issued by trusted authorities, enabling trust.