Minor changes made by Matt Caswell.
Reviewed-by: Dr. Stephen Henson <steve@openssl.org>
(cherry picked from commit 34890ac18e)
		
	
		
			
				
	
	
		
			100 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
			
		
		
	
	
			100 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
=pod
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=head1 NAME
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EVP_PKEY_encrypt_init, EVP_PKEY_encrypt - encrypt using a public key algorithm
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=head1 SYNOPSIS
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 #include <openssl/evp.h>
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 int EVP_PKEY_encrypt_init(EVP_PKEY_CTX *ctx);
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 int EVP_PKEY_encrypt(EVP_PKEY_CTX *ctx,
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			unsigned char *out, size_t *outlen,
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			const unsigned char *in, size_t inlen);
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=head1 DESCRIPTION
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The EVP_PKEY_encrypt_init() function initializes a public key algorithm
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context using key B<pkey> for an encryption operation.
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The EVP_PKEY_encrypt() function performs a public key encryption operation
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using B<ctx>. The data to be encrypted is specified using the B<in> and
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B<inlen> parameters. If B<out> is B<NULL> then the maximum size of the output
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buffer is written to the B<outlen> parameter. If B<out> is not B<NULL> then
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before the call the B<outlen> parameter should contain the length of the
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B<out> buffer, if the call is successful the encrypted data is written to
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B<out> and the amount of data written to B<outlen>.
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=head1 NOTES
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After the call to EVP_PKEY_encrypt_init() algorithm specific control
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operations can be performed to set any appropriate parameters for the
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operation.
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The function EVP_PKEY_encrypt() can be called more than once on the same
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context if several operations are performed using the same parameters.
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=head1 RETURN VALUES
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EVP_PKEY_encrypt_init() and EVP_PKEY_encrypt() return 1 for success and 0
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or a negative value for failure. In particular a return value of -2
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indicates the operation is not supported by the public key algorithm.
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=head1 EXAMPLE
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Encrypt data using OAEP (for RSA keys). See also L<PEM_read_PUBKEY(3)|pem(3)> or
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L<d2i_X509(3)|d2i_X509(3)> for means to load a public key. You may also simply
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set 'eng = NULL;' to start with the default OpenSSL RSA implementation:
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 #include <openssl/evp.h>
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 #include <openssl/rsa.h>
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 #include <openssl/engine.h>
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 EVP_PKEY_CTX *ctx;
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 ENGINE *eng;
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 unsigned char *out, *in;
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 size_t outlen, inlen; 
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 EVP_PKEY *key;
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 /* NB: assumes eng, key, in, inlen are already set up,
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  * and that key is an RSA public key
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  */
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 ctx = EVP_PKEY_CTX_new(key,eng);
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 if (!ctx)
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	/* Error occurred */
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 if (EVP_PKEY_encrypt_init(ctx) <= 0)
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	/* Error */
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 if (EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_OAEP_PADDING) <= 0)
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	/* Error */
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 /* Determine buffer length */
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 if (EVP_PKEY_encrypt(ctx, NULL, &outlen, in, inlen) <= 0)
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	/* Error */
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 out = OPENSSL_malloc(outlen);
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 if (!out)
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	/* malloc failure */
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 if (EVP_PKEY_encrypt(ctx, out, &outlen, in, inlen) <= 0)
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	/* Error */
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 /* Encrypted data is outlen bytes written to buffer out */
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=head1 SEE ALSO
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L<d2i_X509(3)|d2i_X509(3)>,
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L<engine(3)|engine(3)>,
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L<EVP_PKEY_CTX_new(3)|EVP_PKEY_CTX_new(3)>,
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L<EVP_PKEY_decrypt(3)|EVP_PKEY_decrypt(3)>,
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L<EVP_PKEY_sign(3)|EVP_PKEY_sign(3)>,
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L<EVP_PKEY_verify(3)|EVP_PKEY_verify(3)>,
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L<EVP_PKEY_verify_recover(3)|EVP_PKEY_verify_recover(3)>,
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L<EVP_PKEY_derive(3)|EVP_PKEY_derive(3)> 
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=head1 HISTORY
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These functions were first added to OpenSSL 1.0.0.
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=cut
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