table of contents
PKCS7_ENCRYPT(3) | Library Functions Manual | PKCS7_ENCRYPT(3) |
NAME¶
PKCS7_encrypt
—
create a PKCS#7 envelopedData structure
SYNOPSIS¶
#include
<openssl/pkcs7.h>
PKCS7 *
PKCS7_encrypt
(STACK_OF(X509)
*certs, BIO *in, const
EVP_CIPHER *cipher, int flags);
DESCRIPTION¶
PKCS7_encrypt
()
creates and returns a PKCS#7 envelopedData structure.
certs is a list of recipient certificates.
in is the content to be encrypted.
cipher is the symmetric cipher to use.
flags is an optional set of flags.
Only RSA keys are supported in PKCS#7 and envelopedData so the recipient certificates supplied to this function must all contain RSA public keys, though they do not have to be signed using the RSA algorithm.
The algorithm passed in the cipher parameter must support ASN.1 encoding of its parameters.
Many browsers implement a "sign and
encrypt" option which is simply an S/MIME envelopedData containing an
S/MIME signed message. This can be readily produced by storing the S/MIME
signed message in a memory BIO and passing it to
PKCS7_encrypt
().
The following flags can be passed in the flags parameter.
If the PKCS7_TEXT
flag is
set, MIME headers for type
text/plain are
prepended to the data.
Normally the supplied content is translated into MIME canonical
format (as required by the S/MIME specifications). If
PKCS7_BINARY
is set, no translation occurs. This
option should be used if the supplied data is in binary format; otherwise,
the translation will corrupt it. If PKCS7_BINARY
is
set, then PKCS7_TEXT
is ignored.
If the PKCS7_STREAM
flag is set, a partial
PKCS7 structure is output suitable for streaming I/O:
no data is read from in.
If the flag PKCS7_STREAM
is set,
the returned PKCS7 structure is
not complete and
outputting its contents via a function that does not properly finalize the
PKCS7 structure will give unpredictable results.
Several functions including
PKCS7_final(3), SMIME_write_PKCS7(3),
PEM_write_bio_PKCS7_stream(3), and
i2d_PKCS7_bio_stream(3) finalize the structure.
Alternatively finalization can be performed by obtaining the streaming ASN.1
BIO directly using
BIO_new_PKCS7
().
RETURN VALUES¶
PKCS7_encrypt
() returns either a
PKCS7 structure or NULL
if an
error occurred. The error can be obtained from
ERR_get_error(3).
SEE ALSO¶
PKCS7_decrypt(3), PKCS7_final(3), PKCS7_new(3), PKCS7_sign(3)
HISTORY¶
PKCS7_encrypt
() first appeared in OpenSSL
0.9.5 and has been available since OpenBSD 2.7.
The PKCS7_STREAM
flag was first supported
in OpenSSL 1.0.0.
June 3, 2020 | Linux 6.4.0-150600.23.25-default |