EVP_PKEY_encrypt.pod 3.1 KB

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  1. =pod
  2. =head1 NAME
  3. EVP_PKEY_encrypt_init, EVP_PKEY_encrypt - encrypt using a public key algorithm
  4. =head1 SYNOPSIS
  5. #include <openssl/evp.h>
  6. int EVP_PKEY_encrypt_init(EVP_PKEY_CTX *ctx);
  7. int EVP_PKEY_encrypt(EVP_PKEY_CTX *ctx,
  8. unsigned char *out, size_t *outlen,
  9. const unsigned char *in, size_t inlen);
  10. =head1 DESCRIPTION
  11. The EVP_PKEY_encrypt_init() function initializes a public key algorithm
  12. context using key B<pkey> for an encryption operation.
  13. The EVP_PKEY_encrypt() function performs a public key encryption operation
  14. using B<ctx>. The data to be encrypted is specified using the B<in> and
  15. B<inlen> parameters. If B<out> is B<NULL> then the maximum size of the output
  16. buffer is written to the B<outlen> parameter. If B<out> is not B<NULL> then
  17. before the call the B<outlen> parameter should contain the length of the
  18. B<out> buffer, if the call is successful the encrypted data is written to
  19. B<out> and the amount of data written to B<outlen>.
  20. =head1 NOTES
  21. After the call to EVP_PKEY_encrypt_init() algorithm specific control
  22. operations can be performed to set any appropriate parameters for the
  23. operation.
  24. The function EVP_PKEY_encrypt() can be called more than once on the same
  25. context if several operations are performed using the same parameters.
  26. =head1 RETURN VALUES
  27. EVP_PKEY_encrypt_init() and EVP_PKEY_encrypt() return 1 for success and 0
  28. or a negative value for failure. In particular a return value of -2
  29. indicates the operation is not supported by the public key algorithm.
  30. =head1 EXAMPLE
  31. Encrypt data using OAEP (for RSA keys). See also L<PEM_read_PUBKEY(3)> or
  32. L<d2i_X509(3)> for means to load a public key. You may also simply
  33. set 'eng = NULL;' to start with the default OpenSSL RSA implementation:
  34. #include <openssl/evp.h>
  35. #include <openssl/rsa.h>
  36. #include <openssl/engine.h>
  37. EVP_PKEY_CTX *ctx;
  38. ENGINE *eng;
  39. unsigned char *out, *in;
  40. size_t outlen, inlen;
  41. EVP_PKEY *key;
  42. /*
  43. * NB: assumes eng, key, in, inlen are already set up,
  44. * and that key is an RSA public key
  45. */
  46. ctx = EVP_PKEY_CTX_new(key, eng);
  47. if (!ctx)
  48. /* Error occurred */
  49. if (EVP_PKEY_encrypt_init(ctx) <= 0)
  50. /* Error */
  51. if (EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_OAEP_PADDING) <= 0)
  52. /* Error */
  53. /* Determine buffer length */
  54. if (EVP_PKEY_encrypt(ctx, NULL, &outlen, in, inlen) <= 0)
  55. /* Error */
  56. out = OPENSSL_malloc(outlen);
  57. if (!out)
  58. /* malloc failure */
  59. if (EVP_PKEY_encrypt(ctx, out, &outlen, in, inlen) <= 0)
  60. /* Error */
  61. /* Encrypted data is outlen bytes written to buffer out */
  62. =head1 SEE ALSO
  63. L<d2i_X509(3)>,
  64. L<ENGINE_by_id(3)>,
  65. L<EVP_PKEY_CTX_new(3)>,
  66. L<EVP_PKEY_decrypt(3)>,
  67. L<EVP_PKEY_sign(3)>,
  68. L<EVP_PKEY_verify(3)>,
  69. L<EVP_PKEY_verify_recover(3)>,
  70. L<EVP_PKEY_derive(3)>
  71. =head1 HISTORY
  72. These functions were first added to OpenSSL 1.0.0.
  73. =head1 COPYRIGHT
  74. Copyright 2006-2016 The OpenSSL Project Authors. All Rights Reserved.
  75. Licensed under the OpenSSL license (the "License"). You may not use
  76. this file except in compliance with the License. You can obtain a copy
  77. in the file LICENSE in the source distribution or at
  78. L<https://www.openssl.org/source/license.html>.
  79. =cut