67 lines
2.2 KiB
Text
67 lines
2.2 KiB
Text
=pod
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=head1 NAME
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PKCS7_encrypt - create a PKCS#7 envelopedData structure
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=head1 SYNOPSIS
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#include <openssl/pkcs7.h>
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PKCS7 *PKCS7_encrypt(STACK_OF(X509) *certs, BIO *in, const EVP_CIPHER *cipher, int flags);
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=head1 DESCRIPTION
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PKCS7_encrypt() creates and returns a PKCS#7 envelopedData structure. B<certs>
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is a list of recipient certificates. B<in> is the content to be encrypted.
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B<cipher> is the symmetric cipher to use. B<flags> is an optional set of flags.
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=head1 NOTES
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Only RSA keys are supported in PKCS#7 and envelopedData so the recipient certificates
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supplied to this function must all contain RSA public keys, though they do not have to
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be signed using the RSA algorithm.
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EVP_des_ede3_cbc() (triple DES) is the algorithm of choice for S/MIME use because
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most clients will support it.
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Some old "export grade" clients may only support weak encryption using 40 or 64 bit
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RC2. These can be used by passing EVP_rc2_40_cbc() and EVP_rc2_64_cbc() respectively.
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The algorithm passed in the B<cipher> parameter must support ASN1 encoding of its
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parameters.
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Many browsers implement a "sign and encrypt" option which is simply an S/MIME
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envelopedData containing an S/MIME signed message. This can be readily produced
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by storing the S/MIME signed message in a memory BIO and passing it to
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PKCS7_encrypt().
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The following flags can be passed in the B<flags> parameter.
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If the B<PKCS7_TEXT> flag is set MIME headers for type B<text/plain> are prepended
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to the data.
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Normally the supplied content is translated into MIME canonical format (as required
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by the S/MIME specifications) if B<PKCS7_BINARY> is set no translation occurs. This
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option should be used if the supplied data is in binary format otherwise the translation
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will corrupt it. If B<PKCS7_BINARY> is set then B<PKCS7_TEXT> is ignored.
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=head1 RETURN VALUES
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PKCS7_encrypt() returns either a valid PKCS7 structure or NULL if an error occurred.
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The error can be obtained from ERR_get_error(3).
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=head1 BUGS
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The lack of single pass processing and need to hold all data in memory as
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mentioned in PKCS7_sign() also applies to PKCS7_verify().
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=head1 SEE ALSO
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L<ERR_get_error(3)|ERR_get_error(3)>, L<PKCS7_decrypt(3)|PKCS7_decrypt(3)>
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=head1 HISTORY
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PKCS7_decrypt() was added to OpenSSL 0.9.5
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=cut
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