=head1 NAME
-EVP_EncryptInit, EVP_EncryptUpdate, EVP_EncryptFinal, EVP_DecryptInit,
-EVP_DecryptUpdate, EVP_DecryptFinal, EVP_CipherInit, EVP_CipherUpdate,
-EVP_CipherFinal, EVP_CIPHER_CTX_set_key_length, EVP_CIPHER_CTX_ctrl,
-EVP_CIPHER_CTX_cleanup, EVP_get_cipherbyname, EVP_get_cipherbynid,
-EVP_get_cipherbyobj, EVP_CIPHER_nid, EVP_CIPHER_block_size,
-EVP_CIPHER_key_length, EVP_CIPHER_iv_length, EVP_CIPHER_flags,
-EVP_CIPHER_mode, EVP_CIPHER_type, EVP_CIPHER_CTX_cipher, EVP_CIPHER_CTX_nid,
-EVP_CIPHER_CTX_block_size, EVP_CIPHER_CTX_key_length, EVP_CIPHER_CTX_iv_length,
-EVP_CIPHER_CTX_get_app_data, EVP_CIPHER_CTX_set_app_data, EVP_CIPHER_CTX_type,
-EVP_CIPHER_CTX_flags, EVP_CIPHER_CTX_mode, EVP_CIPHER_param_to_asn1,
-EVP_CIPHER_asn1_to_param, EVP_CIPHER_CTX_set_padding - EVP cipher routines
+EVP_CIPHER_CTX_init, EVP_EncryptInit_ex, EVP_EncryptUpdate,
+EVP_EncryptFinal_ex, EVP_DecryptInit_ex, EVP_DecryptUpdate,
+EVP_DecryptFinal_ex, EVP_CipherInit_ex, EVP_CipherUpdate,
+EVP_CipherFinal_ex, EVP_CIPHER_CTX_set_key_length,
+EVP_CIPHER_CTX_ctrl, EVP_CIPHER_CTX_cleanup, EVP_EncryptInit,
+EVP_EncryptFinal, EVP_DecryptInit, EVP_DecryptFinal,
+EVP_CipherInit, EVP_CipherFinal, EVP_get_cipherbyname,
+EVP_get_cipherbynid, EVP_get_cipherbyobj, EVP_CIPHER_nid,
+EVP_CIPHER_block_size, EVP_CIPHER_key_length, EVP_CIPHER_iv_length,
+EVP_CIPHER_flags, EVP_CIPHER_mode, EVP_CIPHER_type, EVP_CIPHER_CTX_cipher,
+EVP_CIPHER_CTX_nid, EVP_CIPHER_CTX_block_size, EVP_CIPHER_CTX_key_length,
+EVP_CIPHER_CTX_iv_length, EVP_CIPHER_CTX_get_app_data,
+EVP_CIPHER_CTX_set_app_data, EVP_CIPHER_CTX_type, EVP_CIPHER_CTX_flags,
+EVP_CIPHER_CTX_mode, EVP_CIPHER_param_to_asn1, EVP_CIPHER_asn1_to_param,
+EVP_CIPHER_CTX_set_padding - EVP cipher routines
=head1 SYNOPSIS
#include <openssl/evp.h>
- int EVP_EncryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
- unsigned char *key, unsigned char *iv);
+ void EVP_CIPHER_CTX_init(EVP_CIPHER_CTX *a);
+
+ int EVP_EncryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
+ ENGINE *impl, unsigned char *key, unsigned char *iv);
int EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
int *outl, unsigned char *in, int inl);
+ int EVP_EncryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out,
+ int *outl);
+
+ int EVP_DecryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
+ ENGINE *impl, unsigned char *key, unsigned char *iv);
+ int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
+ int *outl, unsigned char *in, int inl);
+ int EVP_DecryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm,
+ int *outl);
+
+ int EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
+ ENGINE *impl, unsigned char *key, unsigned char *iv, int enc);
+ int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
+ int *outl, unsigned char *in, int inl);
+ int EVP_CipherFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm,
+ int *outl);
+
+ int EVP_EncryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
+ unsigned char *key, unsigned char *iv);
int EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out,
int *outl);
int EVP_DecryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
unsigned char *key, unsigned char *iv);
- int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
- int *outl, unsigned char *in, int inl);
int EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm,
int *outl);
int EVP_CipherInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
unsigned char *key, unsigned char *iv, int enc);
- int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
- int *outl, unsigned char *in, int inl);
int EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm,
int *outl);
The EVP cipher routines are a high level interface to certain
symmetric ciphers.
-EVP_EncryptInit() initializes a cipher context B<ctx> for encryption
-with cipher B<type>. B<type> is normally supplied by a function such
-as EVP_des_cbc() . B<key> is the symmetric key to use and B<iv> is the
-IV to use (if necessary), the actual number of bytes used for the
-key and IV depends on the cipher. It is possible to set all parameters
-to NULL except B<type> in an initial call and supply the remaining
-parameters in subsequent calls, all of which have B<type> set to NULL.
-This is done when the default cipher parameters are not appropriate.
+EVP_CIPHER_CTX_init() initializes cipher contex B<ctx>.
+
+EVP_EncryptInit_ex() sets up cipher context B<ctx> for encryption
+with cipher B<type> from ENGINE B<impl>. B<ctx> must be initialized
+before calling this function. B<type> is normally supplied
+by a function such as EVP_des_cbc(). If B<impl> is NULL then the
+default implementation is used. B<key> is the symmetric key to use
+and B<iv> is the IV to use (if necessary), the actual number of bytes
+used for the key and IV depends on the cipher. It is possible to set
+all parameters to NULL except B<type> in an initial call and supply
+the remaining parameters in subsequent calls, all of which have B<type>
+set to NULL. This is done when the default cipher parameters are not
+appropriate.
EVP_EncryptUpdate() encrypts B<inl> bytes from the buffer B<in> and
writes the encrypted version to B<out>. This function can be called
to (inl + cipher_block_size - 1) so B<outl> should contain sufficient
room. The actual number of bytes written is placed in B<outl>.
-If padding is enabled (the default) then EVP_EncryptFinal() encrypts
+If padding is enabled (the default) then EVP_EncryptFinal_ex() encrypts
the "final" data, that is any data that remains in a partial block.
It uses L<standard block padding|/NOTES> (aka PKCS padding). The encrypted
final data is written to B<out> which should have sufficient space for
this function is called the encryption operation is finished and no further
calls to EVP_EncryptUpdate() should be made.
-If padding is disabled then EVP_EncryptFinal() will not encrypt any more
+If padding is disabled then EVP_EncryptFinal_ex() will not encrypt any more
data and it will return an error if any data remains in a partial block:
that is if the total data length is not a multiple of the block size.
-EVP_DecryptInit(), EVP_DecryptUpdate() and EVP_DecryptFinal() are the
+EVP_DecryptInit_ex(), EVP_DecryptUpdate() and EVP_DecryptFinal_ex() are the
corresponding decryption operations. EVP_DecryptFinal() will return an
error code if padding is enabled and the final block is not correctly
formatted. The parameters and restrictions are identical to the encryption
(B<inl> + cipher_block_size) bytes unless the cipher block size is 1 in
which case B<inl> bytes is sufficient.
-EVP_CipherInit(), EVP_CipherUpdate() and EVP_CipherFinal() are functions
-that can be used for decryption or encryption. The operation performed
-depends on the value of the B<enc> parameter. It should be set to 1 for
-encryption, 0 for decryption and -1 to leave the value unchanged (the
-actual value of 'enc' being supplied in a previous call).
+EVP_CipherInit_ex(), EVP_CipherUpdate() and EVP_CipherFinal_ex() are
+functions that can be used for decryption or encryption. The operation
+performed depends on the value of the B<enc> parameter. It should be set
+to 1 for encryption, 0 for decryption and -1 to leave the value unchanged
+(the actual value of 'enc' being supplied in a previous call).
+
+EVP_CIPHER_CTX_cleanup() clears all information from a cipher context
+and free up any allocated memory associate with it. It should be called
+after all operations using a cipher are complete so sensitive information
+does not remain in memory.
+
+EVP_EncryptInit(), EVP_DecryptInit() and EVP_CipherInit() behave in a
+similar way to EVP_EncryptInit_ex(), EVP_DecryptInit_ex and
+EVP_CipherInit_ex() except the B<ctx> paramter does not need to be
+initialized and they always use the default cipher implementation.
-EVP_CIPHER_CTX_cleanup() clears all information from a cipher context.
-It should be called after all operations using a cipher are complete
-so sensitive information does not remain in memory.
+EVP_EncryptFinal(), EVP_DecryptFinal() and EVP_CipherFinal() behave in a
+similar way to EVP_EncryptFinal_ex(), EVP_DecryptFinal_ex() and
+EVP_CipherFinal_ex() except B<ctx> is automatically cleaned up
+after the call.
EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj()
return an EVP_CIPHER structure when passed a cipher name, a NID or an
=head1 RETURN VALUES
-EVP_EncryptInit(), EVP_EncryptUpdate() and EVP_EncryptFinal() return 1 for success
-and 0 for failure.
+EVP_EncryptInit_ex(), EVP_EncryptUpdate() and EVP_EncryptFinal_ex()
+return 1 for success and 0 for failure.
-EVP_DecryptInit() and EVP_DecryptUpdate() return 1 for success and 0 for failure.
-EVP_DecryptFinal() returns 0 if the decrypt failed or 1 for success.
+EVP_DecryptInit_ex() and EVP_DecryptUpdate() return 1 for success and 0 for failure.
+EVP_DecryptFinal_ex() returns 0 if the decrypt failed or 1 for success.
-EVP_CipherInit() and EVP_CipherUpdate() return 1 for success and 0 for failure.
-EVP_CipherFinal() returns 1 for a decryption failure or 1 for success.
+EVP_CipherInit_ex() and EVP_CipherUpdate() return 1 for success and 0 for failure.
+EVP_CipherFinal_ex() returns 0 for a decryption failure or 1 for success.
EVP_CIPHER_CTX_cleanup() returns 1 for success and 0 for failure.
If padding is disabled then the decryption operation will always succeed if
the total amount of data decrypted is a multiple of the block size.
-The functions EVP_EncryptInit(), EVP_EncryptUpdate(), EVP_EncryptFinal(),
-EVP_DecryptInit(), EVP_DecryptUpdate(), EVP_CipherInit() and EVP_CipherUpdate()
-and EVP_CIPHER_CTX_cleanup() did not return errors in OpenSSL version 0.9.5a or
-earlier. Software only versions of encryption algorithms will never return
-error codes for these functions, unless there is a programming error (for example
-and attempt to set the key before the cipher is set in EVP_EncryptInit() ).
+The functions EVP_EncryptInit(), EVP_EncryptFinal(), EVP_DecryptInit(),
+EVP_CipherInit() and EVP_CipherFinal() are obsolete but are retained for
+compatibility with existing code. New code should use EVP_EncryptInit_ex(),
+EVP_EncryptFinal_ex(), EVP_DecryptInit_ex(), EVP_DecryptFinal_ex(),
+EVP_CipherInit_ex() and EVP_CipherFinal_ex() because they can reuse an
+existing context without allocating and freeing it up on each call.
=head1 BUGS
int key_bits;
EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_SET_RC2_KEY_BITS, key_bits, NULL);
+Encrypt a string using blowfish:
+
+ int do_crypt(char *outfile)
+ {
+ unsigned char outbuf[1024];
+ int outlen, tmplen;
+ /* Bogus key and IV: we'd normally set these from
+ * another source.
+ */
+ unsigned char key[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
+ unsigned char iv[] = {1,2,3,4,5,6,7,8};
+ char intext[] = "Some Crypto Text";
+ EVP_CIPHER_CTX ctx;
+ FILE *out;
+ EVP_CIPHER_CTX_init(&ctx);
+ EVP_EncryptInit_ex(&ctx, EVP_bf_cbc(), NULL, key, iv);
+
+ if(!EVP_EncryptUpdate(&ctx, outbuf, &outlen, intext, strlen(intext)))
+ {
+ /* Error */
+ return 0;
+ }
+ /* Buffer passed to EVP_EncryptFinal() must be after data just
+ * encrypted to avoid overwriting it.
+ */
+ if(!EVP_EncryptFinal_ex(&ctx, outbuf + outlen, &tmplen))
+ {
+ /* Error */
+ return 0;
+ }
+ outlen += tmplen;
+ EVP_CIPHER_CTX_cleanup(&ctx);
+ /* Need binary mode for fopen because encrypted data is
+ * binary data. Also cannot use strlen() on it because
+ * it wont be null terminated and may contain embedded
+ * nulls.
+ */
+ out = fopen(outfile, "wb");
+ fwrite(outbuf, 1, outlen, out);
+ fclose(out);
+ return 1;
+ }
+
+The ciphertext from the above example can be decrypted using the B<openssl>
+utility with the command line:
+
+ S<openssl bf -in cipher.bin -K 000102030405060708090A0B0C0D0E0F -iv 0102030405060708 -d>
+
+General encryption, decryption function example using FILE I/O and RC2 with an
+80 bit key:
+
+ int do_crypt(FILE *in, FILE *out, int do_encrypt)
+ {
+ /* Allow enough space in output buffer for additional block */
+ inbuf[1024], outbuf[1024 + EVP_MAX_BLOCK_LENGTH];
+ int inlen, outlen;
+ /* Bogus key and IV: we'd normally set these from
+ * another source.
+ */
+ unsigned char key[] = "0123456789";
+ unsigned char iv[] = "12345678";
+ /* Don't set key or IV because we will modify the parameters */
+ EVP_CIPHER_CTX_init(&ctx);
+ EVP_CipherInit_ex(&ctx, EVP_rc2(), NULL, NULL, NULL, do_encrypt);
+ EVP_CIPHER_CTX_set_key_length(&ctx, 10);
+ /* We finished modifying parameters so now we can set key and IV */
+ EVP_CipherInit_ex(&ctx, NULL, NULL, key, iv, do_encrypt);
+
+ for(;;)
+ {
+ inlen = fread(inbuf, 1, 1024, in);
+ if(inlen <= 0) break;
+ if(!EVP_CipherUpdate(&ctx, outbuf, &outlen, inbuf, inlen))
+ {
+ /* Error */
+ EVP_CIPHER_CTX_cleanup(&ctx);
+ return 0;
+ }
+ fwrite(outbuf, 1, outlen, out);
+ }
+ if(!EVP_CipherFinal_ex(&ctx, outbuf, &outlen))
+ {
+ /* Error */
+ EVP_CIPHER_CTX_cleanup(&ctx);
+ return 0;
+ }
+ fwrite(outbuf, 1, outlen, out);
+
+ EVP_CIPHER_CTX_cleanup(&ctx);
+ return 1;
+ }
+
+
=head1 SEE ALSO
L<evp(3)|evp(3)>
=head1 HISTORY
+EVP_CIPHER_CTX_init(), EVP_EncryptInit_ex(), EVP_EncryptFinal_ex(),
+EVP_DecryptInit_ex(), EVP_DecryptFinal_ex(), EVP_CipherInit_ex(),
+EVP_CipherFinal_ex() and EVP_CIPHER_CTX_set_padding() appeared in
+OpenSSL 0.9.7.
+
=cut
projects / openssl.git / blobdiff