1RSA_PRIVATE_ENCRYPT(3ossl)          OpenSSL         RSA_PRIVATE_ENCRYPT(3ossl)
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NAME

6       RSA_private_encrypt, RSA_public_decrypt - low-level signature
7       operations
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SYNOPSIS

10        #include <openssl/rsa.h>
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12       The following functions have been deprecated since OpenSSL 3.0, and can
13       be hidden entirely by defining OPENSSL_API_COMPAT with a suitable
14       version value, see openssl_user_macros(7):
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16        int RSA_private_encrypt(int flen, unsigned char *from,
17                                unsigned char *to, RSA *rsa, int padding);
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19        int RSA_public_decrypt(int flen, unsigned char *from,
20                               unsigned char *to, RSA *rsa, int padding);
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DESCRIPTION

23       Both of the functions described on this page are deprecated.
24       Applications should instead use EVP_PKEY_sign_init_ex(3),
25       EVP_PKEY_sign(3), EVP_PKEY_verify_recover_init(3), and
26       EVP_PKEY_verify_recover(3).
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28       These functions handle RSA signatures at a low-level.
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30       RSA_private_encrypt() signs the flen bytes at from (usually a message
31       digest with an algorithm identifier) using the private key rsa and
32       stores the signature in to. to must point to RSA_size(rsa) bytes of
33       memory.
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35       padding denotes one of the following modes:
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37       RSA_PKCS1_PADDING
38           PKCS #1 v1.5 padding. This function does not handle the
39           algorithmIdentifier specified in PKCS #1. When generating or
40           verifying PKCS #1 signatures, RSA_sign(3) and RSA_verify(3) should
41           be used.
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43       RSA_NO_PADDING
44           Raw RSA signature. This mode should only be used to implement
45           cryptographically sound padding modes in the application code.
46           Signing user data directly with RSA is insecure.
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48       RSA_public_decrypt() recovers the message digest from the flen bytes
49       long signature at from using the signer's public key rsa. to must point
50       to a memory section large enough to hold the message digest (which is
51       smaller than RSA_size(rsa) - 11). padding is the padding mode that was
52       used to sign the data.
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RETURN VALUES

55       RSA_private_encrypt() returns the size of the signature (i.e.,
56       RSA_size(rsa)). RSA_public_decrypt() returns the size of the recovered
57       message digest.
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59       On error, -1 is returned; the error codes can be obtained by
60       ERR_get_error(3).
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SEE ALSO

63       ERR_get_error(3), RSA_sign(3), RSA_verify(3), EVP_PKEY_sign(3),
64       EVP_PKEY_verify_recover(3)
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HISTORY

67       Both of these functions were deprecated in OpenSSL 3.0.
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70       Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.
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72       Licensed under the Apache License 2.0 (the "License").  You may not use
73       this file except in compliance with the License.  You can obtain a copy
74       in the file LICENSE in the source distribution or at
75       <https://www.openssl.org/source/license.html>.
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793.1.1                             2023-08-31        RSA_PRIVATE_ENCRYPT(3ossl)
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