The AEAD documentation conflates associated data and authentication tags: the former (along with the ciphertext) is authenticated by the latter. Fix the doc accordingly. Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> --- include/crypto/aead.h | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/include/crypto/aead.h b/include/crypto/aead.h index 14db3bee0519ee85..4a2b7e6e0c1fa7cd 100644 --- a/include/crypto/aead.h +++ b/include/crypto/aead.h @@ -27,15 +27,12 @@ * * For example: authenc(hmac(sha256), cbc(aes)) * - * The example code provided for the symmetric key cipher operation - * applies here as well. Naturally all *skcipher* symbols must be exchanged - * the *aead* pendants discussed in the following. In addition, for the AEAD - * operation, the aead_request_set_ad function must be used to set the - * pointer to the associated data memory location before performing the - * encryption or decryption operation. In case of an encryption, the associated - * data memory is filled during the encryption operation. For decryption, the - * associated data memory must contain data that is used to verify the integrity - * of the decrypted data. Another deviation from the asynchronous block cipher + * The example code provided for the symmetric key cipher operation applies + * here as well. Naturally all *skcipher* symbols must be exchanged the *aead* + * pendants discussed in the following. In addition, for the AEAD operation, + * the aead_request_set_ad function must be used to set the pointer to the + * associated data memory location before performing the encryption or + * decryption operation. Another deviation from the asynchronous block cipher * operation is that the caller should explicitly check for -EBADMSG of the * crypto_aead_decrypt. That error indicates an authentication error, i.e. * a breach in the integrity of the message. In essence, that -EBADMSG error @@ -49,7 +46,10 @@ * * The destination scatterlist has the same layout, except that the plaintext * (resp. ciphertext) will grow (resp. shrink) by the authentication tag size - * during encryption (resp. decryption). + * during encryption (resp. decryption). The authentication tag is generated + * during the encryption operation and appended to the ciphertext. During + * decryption, the authentication tag is consumed along with the ciphertext and + * used to verify the integrity of the plaintext and the associated data. * * In-place encryption/decryption is enabled by using the same scatterlist * pointer for both the source and destination. -- 2.35.1
