#include <openssl/evp.h> int EVP_PKEY_encrypt_init(EVP_PKEY_CTX *ctx); int EVP_PKEY_encrypt(EVP_PKEY_CTX *ctx, unsigned char *out, size_t *outlen, const unsigned char *in, size_t inlen);
The EVP_PKEY_encrypt() function performs a public key encryption operation using ctx. The data to be encrypted is specified using the in and inlen parameters. If out is NULL then the maximum size of the output buffer is written to the outlen parameter. If out is not NULL then before the call the outlen parameter should contain the length of the out buffer, if the call is successful the encrypted data is written to out and the amount of data written to outlen.
The function EVP_PKEY_encrypt() can be called more than once on the same context if several operations are performed using the same parameters.
#include <openssl/evp.h> #include <openssl/rsa.h> EVP_PKEY_CTX *ctx; unsigned char *out, *in; size_t outlen, inlen; EVP_PKEY *key; /* NB: assumes key in, inlen are already set up * and that key is an RSA public key */ ctx = EVP_PKEY_CTX_new(key); if (!ctx) /* Error occurred */ if (EVP_PKEY_encrypt_init(ctx) <= 0) /* Error */ if (EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_OAEP_PADDING) <= 0) /* Error */ /* Determine buffer length */ if (EVP_PKEY_encrypt(ctx, NULL, &outlen, in, inlen) <= 0) /* Error */ out = OPENSSL_malloc(outlen); if (!out) /* malloc failure */ if (EVP_PKEY_encrypt(ctx, out, &outlen, in, inlen) <= 0) /* Error */ /* Encrypted data is outlen bytes written to buffer out */