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-rw-r--r-- | doc/crypto/EVP_SealInit.pod | 26 |
1 files changed, 16 insertions, 10 deletions
diff --git a/doc/crypto/EVP_SealInit.pod b/doc/crypto/EVP_SealInit.pod index 25ef07f7c7..b5e477e294 100644 --- a/doc/crypto/EVP_SealInit.pod +++ b/doc/crypto/EVP_SealInit.pod @@ -18,22 +18,28 @@ EVP_SealInit, EVP_SealUpdate, EVP_SealFinal - EVP envelope encryption =head1 DESCRIPTION The EVP envelope routines are a high level interface to envelope -encryption. They generate a random key and then "envelope" it by -using public key encryption. Data can then be encrypted using this -key. +encryption. They generate a random key and IV (if required) then +"envelope" it by using public key encryption. Data can then be +encrypted using this key. EVP_SealInit() initializes a cipher context B<ctx> for encryption -with cipher B<type> using a random secret key and IV supplied in -the B<iv> parameter. B<type> is normally supplied by a function such -as EVP_des_cbc(). The secret key is encrypted using one or more public -keys, this allows the same encrypted data to be decrypted using any -of the corresponding private keys. B<ek> is an array of buffers where -the public key encrypted secret key will be written, each buffer must -contain enough room for the corresponding encrypted key: that is +with cipher B<type> using a random secret key and IV. B<type> is normally +supplied by a function such as EVP_des_cbc(). The secret key is encrypted +using one or more public keys, this allows the same encrypted data to be +decrypted using any of the corresponding private keys. B<ek> is an array of +buffers where the public key encrypted secret key will be written, each buffer +must contain enough room for the corresponding encrypted key: that is B<ek[i]> must have room for B<EVP_PKEY_size(pubk[i])> bytes. The actual size of each encrypted secret key is written to the array B<ekl>. B<pubk> is an array of B<npubk> public keys. +The B<iv> parameter is a buffer where the generated IV is written to. It must +contain enough room for the corresponding cipher's IV, as determined by (for +example) EVP_CIPHER_iv_length(type). + +If the cipher does not require an IV then the B<iv> parameter is ignored +and can be B<NULL>. + EVP_SealUpdate() and EVP_SealFinal() have exactly the same properties as the EVP_EncryptUpdate() and EVP_EncryptFinal() routines, as documented on the L<EVP_EncryptInit(3)|EVP_EncryptInit(3)> manual |