freebsd-dev/secure/lib/libcrypto/man/PKCS7_encrypt.3

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.IX Title "PKCS7_encrypt 3"
.TH PKCS7_encrypt 3 "0.9.7a" "2003-02-19" "OpenSSL"
.UC
.SH "NAME"
PKCS7_encrypt \- create a PKCS#7 envelopedData structure
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
\&\s-1PKCS7\s0 *PKCS7_encrypt(STACK_OF(X509) *certs, \s-1BIO\s0 *in, const \s-1EVP_CIPHER\s0 *cipher, int flags);
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
\&\fIPKCS7_encrypt()\fR creates and returns a PKCS#7 envelopedData structure. \fBcerts\fR
is a list of recipient certificates. \fBin\fR is the content to be encrypted.
\&\fBcipher\fR is the symmetric cipher to use. \fBflags\fR is an optional set of flags.
.SH "NOTES"
.IX Header "NOTES"
Only \s-1RSA\s0 keys are supported in PKCS#7 and envelopedData so the recipient certificates
supplied to this function must all contain \s-1RSA\s0 public keys, though they do not have to
be signed using the \s-1RSA\s0 algorithm.
.PP
\&\fIEVP_des_ede3_cbc()\fR (triple \s-1DES\s0) is the algorithm of choice for S/MIME use because
most clients will support it.
.PP
Some old \*(L"export grade\*(R" clients may only support weak encryption using 40 or 64 bit
\&\s-1RC2\s0. These can be used by passing \fIEVP_rc2_40_cbc()\fR and \fIEVP_rc2_64_cbc()\fR respectively.
.PP
The algorithm passed in the \fBcipher\fR parameter must support \s-1ASN1\s0 encoding of its
parameters. 
.PP
Many browsers implement a \*(L"sign and encrypt\*(R" 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 \s-1BIO\s0 and passing it to
\&\fIPKCS7_encrypt()\fR.
.PP
The following flags can be passed in the \fBflags\fR parameter.
.PP
If the \fB\s-1PKCS7_TEXT\s0\fR flag is set \s-1MIME\s0 headers for type \fBtext/plain\fR are prepended
to the data.
.PP
Normally the supplied content is translated into \s-1MIME\s0 canonical format (as required
by the S/MIME specifications) if \fB\s-1PKCS7_BINARY\s0\fR 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 \fB\s-1PKCS7_BINARY\s0\fR is set then \fB\s-1PKCS7_TEXT\s0\fR is ignored.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fIPKCS7_encrypt()\fR returns either a valid \s-1PKCS7\s0 structure or \s-1NULL\s0 if an error occurred.
The error can be obtained from \fIERR_get_error\fR\|(3).
.SH "BUGS"
.IX Header "BUGS"
The lack of single pass processing and need to hold all data in memory as
mentioned in \fIPKCS7_sign()\fR also applies to \fIPKCS7_verify()\fR.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
ERR_get_error(3), PKCS7_decrypt(3)
.SH "HISTORY"
.IX Header "HISTORY"
\&\fIPKCS7_decrypt()\fR was added to OpenSSL 0.9.5