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Em muitas bibliotecas criptográficas, as chaves geralmente são identificadas por apenas algumas sequências
de bytes. Considere, por exemplo, funções do OpenSSL, como EVP_EncryptInit_ex,
que, além dos bytes de chave, também precisa do IV para computação; ou o
método javax.crypto Cipher.init, que recebe uma sequência de chaves e um
AlgorithmParameterSpec. Essas funções geralmente são difíceis de usar corretamente
e transmitir os parâmetros errados pode ter consequências graves.
O objetivo do Tink é ser diferente, e ele espera que uma chave sempre consista do material
da chave e dos metadados (os parâmetros).
Por exemplo, uma chave AEAD completa especifica exatamente como a criptografia e
a descriptografia funcionam. Ela especifica as duas funções \(\mathrm{Enc}\) e
\(\mathrm{Dec}\)e como o texto criptografado é codificado (por exemplo, vetor de inicialização,
seguido pela criptografia, seguido pela tag).
Uma chave AES no Tink não é apenas uma sequência de bytes de comprimento 128, 192 ou 256 bits,
mas também armazena as especificações do algoritmo correspondente necessárias para calcular
a chave, na forma de um objeto parameters. Portanto, uma chave AES-EAX completa e uma chave AES-GCM completa são objetos diferentes no Tink.
[null,null,["Última atualização 2025-07-25 UTC."],[[["\u003cp\u003eIn Tink, a Key is a cryptographic object encompassing both key material and metadata, ensuring clear and complete functionality specification.\u003c/p\u003e\n"],["\u003cp\u003eUnlike traditional libraries, Tink Keys include necessary parameters like IV and algorithm specifications, simplifying usage and mitigating potential errors.\u003c/p\u003e\n"],["\u003cp\u003eTink Keys fully define cryptographic operations, including encryption, decryption, and ciphertext encoding, as exemplified by AEAD keys.\u003c/p\u003e\n"],["\u003cp\u003eDifferent key types with distinct algorithm specifications, like AES-EAX and AES-GCM, are treated as separate objects within Tink.\u003c/p\u003e\n"],["\u003cp\u003eTink incorporates Keys into Keysets, enabling key rotation and enhanced security practices.\u003c/p\u003e\n"]]],["Tink's **Key** includes both key material and metadata, defining its functionality. Unlike other libraries that only use byte sequences, Tink requires complete parameter specifications. A full AEAD key defines encryption and decryption processes, along with ciphertext encoding. AES keys in Tink include algorithm specifications, making different AES types distinct objects. Keys in Tink exist as parts of a set of keys called a Keyset, allowing key rotation.\n"],null,["# Keys\n\n| In Tink, a **Key** describes a complete cryptographic object, and consists of the key material plus all necessary metadata which describes its functionality.\n\nIn many cryptographic libraries, keys are often identified by only some byte\nsequences. Consider for example OpenSSL functions such as `EVP_EncryptInit_ex`,\nwhich apart from the key bytes, also needs the IV for computation; or the\njavax.crypto method `Cipher.init`, which takes both a key sequence and an\n`AlgorithmParameterSpec`. Such functions are often difficult to use correctly\nand passing the wrong parameters can have serious consequences.\n\nTink aims to be different, and expects a key to always consist of both the key\nmaterial and the metadata (the parameters).\n\nA full AEAD key for example specifies in exact detail how encryption and\ndecryption works - it specifies the two functions \\\\(\\\\mathrm{Enc}\\\\) and\n\\\\(\\\\mathrm{Dec}\\\\), and how the ciphertext is encoded (e.g. initialization vector,\nfollowed by the encryption, followed by the tag).\n\nAn AES key in Tink is not only a byte sequence of length 128, 192 or 256 bits,\nbut it also stores the corresponding algorithm specifications needed to compute\nthe key, in the form of a [parameters](/tink/design/parameters) object. Hence, a\nfull AES-EAX key and a full AES-GCM key are different objects in Tink.\n| **Note:** In Tink, keys are part of a [keyset](/tink/design/keysets) - a set of keys which implement the same primitive, which facilitates key rotation."]]
