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63 lines
1.9 KiB
63 lines
1.9 KiB
=pod |
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=head1 NAME |
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EVP_OpenInit, EVP_OpenUpdate, EVP_OpenFinal - EVP envelope decryption |
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=head1 SYNOPSIS |
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#include <openssl/evp.h> |
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int EVP_OpenInit(EVP_CIPHER_CTX *ctx,EVP_CIPHER *type,unsigned char *ek, |
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int ekl,unsigned char *iv,EVP_PKEY *priv); |
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int EVP_OpenUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, |
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int *outl, unsigned char *in, int inl); |
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int EVP_OpenFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, |
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int *outl); |
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=head1 DESCRIPTION |
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The EVP envelope routines are a high level interface to envelope |
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decryption. They decrypt a public key encrypted symmetric key and |
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then decrypt data using it. |
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EVP_OpenInit() initializes a cipher context B<ctx> for decryption |
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with cipher B<type>. It decrypts the encrypted symmetric key of length |
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B<ekl> bytes passed in the B<ek> parameter using the private key B<priv>. |
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The IV is supplied in the B<iv> parameter. |
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EVP_OpenUpdate() and EVP_OpenFinal() have exactly the same properties |
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as the EVP_DecryptUpdate() and EVP_DecryptFinal() routines, as |
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documented on the L<EVP_EncryptInit(3)|EVP_EncryptInit(3)> manual |
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page. |
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=head1 NOTES |
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It is possible to call EVP_OpenInit() twice in the same way as |
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EVP_DecryptInit(). The first call should have B<priv> set to NULL |
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and (after setting any cipher parameters) it should be called again |
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with B<type> set to NULL. |
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If the cipher passed in the B<type> parameter is a variable length |
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cipher then the key length will be set to the value of the recovered |
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key length. If the cipher is a fixed length cipher then the recovered |
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key length must match the fixed cipher length. |
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=head1 RETURN VALUES |
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EVP_OpenInit() returns 0 on error or a non zero integer (actually the |
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recovered secret key size) if successful. |
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EVP_OpenUpdate() returns 1 for success or 0 for failure. |
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EVP_OpenFinal() returns 0 if the decrypt failed or 1 for success. |
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=head1 SEE ALSO |
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L<evp(3)|evp(3)>, L<rand(3)|rand(3)>, |
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L<EVP_EncryptInit(3)|EVP_EncryptInit(3)>, |
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L<EVP_SealInit(3)|EVP_SealInit(3)> |
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=head1 HISTORY |
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=cut
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