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Title "EVP_OPENINIT 3"
EVP_OPENINIT 3 "2021-08-24" "1.1.1l" "OpenSSL"
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"NAME"
EVP_OpenInit, EVP_OpenUpdate, EVP_OpenFinal - EVP envelope decryption
"SYNOPSIS"
Header "SYNOPSIS" .Vb 1 #include <openssl/evp.h> \& int EVP_OpenInit(EVP_CIPHER_CTX *ctx, EVP_CIPHER *type, unsigned char *ek, int ekl, unsigned char *iv, EVP_PKEY *priv); int EVP_OpenUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl, unsigned char *in, int inl); int EVP_OpenFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl); .Ve
"DESCRIPTION"
Header "DESCRIPTION" The \s-1EVP\s0 envelope routines are a high-level interface to envelope decryption. They decrypt a public key encrypted symmetric key and then decrypt data using it.

\fBEVP_OpenInit() initializes a cipher context ctx for decryption with cipher type. It decrypts the encrypted symmetric key of length \fBekl bytes passed in the ek parameter using the private key priv. The \s-1IV\s0 is supplied in the iv parameter.

\fBEVP_OpenUpdate() and EVP_OpenFinal() have exactly the same properties as the EVP_DecryptUpdate() and EVP_DecryptFinal() routines, as documented on the EVP_EncryptInit\|(3) manual page.

"NOTES"
Header "NOTES" It is possible to call EVP_OpenInit() twice in the same way as \fBEVP_DecryptInit(). The first call should have priv set to \s-1NULL\s0 and (after setting any cipher parameters) it should be called again with type set to \s-1NULL.\s0

If the cipher passed in the type parameter is a variable length cipher then the key length will be set to the value of the recovered key length. If the cipher is a fixed length cipher then the recovered key length must match the fixed cipher length.

"RETURN VALUES"
Header "RETURN VALUES" \fBEVP_OpenInit() returns 0 on error or a non zero integer (actually the recovered secret key size) if successful.

\fBEVP_OpenUpdate() returns 1 for success or 0 for failure.

\fBEVP_OpenFinal() returns 0 if the decrypt failed or 1 for success.

"SEE ALSO"
Header "SEE ALSO" \fBevp\|(7), RAND_bytes\|(3), \fBEVP_EncryptInit\|(3), \fBEVP_SealInit\|(3)
"COPYRIGHT"
Header "COPYRIGHT" Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (the \*(L"License\*(R"). You may not use this file except in compliance with the License. You can obtain a copy in the file \s-1LICENSE\s0 in the source distribution or at <https://www.openssl.org/source/license.html>.