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authorbeck <>2000-12-15 02:58:47 +0000
committerbeck <>2000-12-15 02:58:47 +0000
commit9200bb13d15da4b2a23e6bc92c20e95b74aa2113 (patch)
tree5c52d628ec1e34be76e7ef2a4235d248b7c44d24 /src/lib/libcrypto/doc/EVP_EncryptInit.pod
parente131d25072e3d4197ba4b9bcc0d1b27d34d6488d (diff)
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openssl-engine-0.9.6 merge
Diffstat (limited to 'src/lib/libcrypto/doc/EVP_EncryptInit.pod')
-rw-r--r--src/lib/libcrypto/doc/EVP_EncryptInit.pod199
1 files changed, 167 insertions, 32 deletions
diff --git a/src/lib/libcrypto/doc/EVP_EncryptInit.pod b/src/lib/libcrypto/doc/EVP_EncryptInit.pod
index 77ed4ccdba..9afe2396e2 100644
--- a/src/lib/libcrypto/doc/EVP_EncryptInit.pod
+++ b/src/lib/libcrypto/doc/EVP_EncryptInit.pod
@@ -2,34 +2,46 @@
2 2
3=head1 NAME 3=head1 NAME
4 4
5EVP_EncryptInit, EVP_EncryptUpdate, EVP_EncryptFinal - EVP cipher routines 5EVP_EncryptInit, EVP_EncryptUpdate, EVP_EncryptFinal, EVP_DecryptInit,
6EVP_DecryptUpdate, EVP_DecryptFinal, EVP_CipherInit, EVP_CipherUpdate,
7EVP_CipherFinal, EVP_CIPHER_CTX_set_key_length, EVP_CIPHER_CTX_ctrl,
8EVP_CIPHER_CTX_cleanup, EVP_get_cipherbyname, EVP_get_cipherbynid,
9EVP_get_cipherbyobj, EVP_CIPHER_nid, EVP_CIPHER_block_size,
10EVP_CIPHER_key_length, EVP_CIPHER_iv_length, EVP_CIPHER_flags,
11EVP_CIPHER_mode, EVP_CIPHER_type, EVP_CIPHER_CTX_cipher, EVP_CIPHER_CTX_nid,
12EVP_CIPHER_CTX_block_size, EVP_CIPHER_CTX_key_length, EVP_CIPHER_CTX_iv_length,
13EVP_CIPHER_CTX_get_app_data, EVP_CIPHER_CTX_set_app_data, EVP_CIPHER_CTX_type,
14EVP_CIPHER_CTX_flags, EVP_CIPHER_CTX_mode, EVP_CIPHER_param_to_asn1,
15EVP_CIPHER_asn1_to_param - EVP cipher routines
6 16
7=head1 SYNOPSIS 17=head1 SYNOPSIS
8 18
9 #include <openssl/evp.h> 19 #include <openssl/evp.h>
10 20
11 void EVP_EncryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, 21 int EVP_EncryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
12 unsigned char *key, unsigned char *iv); 22 unsigned char *key, unsigned char *iv);
13 void EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, 23 int EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
14 int *outl, unsigned char *in, int inl); 24 int *outl, unsigned char *in, int inl);
15 void EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, 25 int EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out,
16 int *outl); 26 int *outl);
17 27
18 void EVP_DecryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, 28 int EVP_DecryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
19 unsigned char *key, unsigned char *iv); 29 unsigned char *key, unsigned char *iv);
20 void EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, 30 int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
21 int *outl, unsigned char *in, int inl); 31 int *outl, unsigned char *in, int inl);
22 int EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm, 32 int EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm,
23 int *outl); 33 int *outl);
24 34
25 void EVP_CipherInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, 35 int EVP_CipherInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
26 unsigned char *key, unsigned char *iv, int enc); 36 unsigned char *key, unsigned char *iv, int enc);
27 void EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, 37 int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
28 int *outl, unsigned char *in, int inl); 38 int *outl, unsigned char *in, int inl);
29 int EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm, 39 int EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm,
30 int *outl); 40 int *outl);
31 41
32 void EVP_CIPHER_CTX_cleanup(EVP_CIPHER_CTX *a); 42 int EVP_CIPHER_CTX_set_key_length(EVP_CIPHER_CTX *x, int keylen);
43 int EVP_CIPHER_CTX_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg, void *ptr);
44 int EVP_CIPHER_CTX_cleanup(EVP_CIPHER_CTX *a);
33 45
34 const EVP_CIPHER *EVP_get_cipherbyname(const char *name); 46 const EVP_CIPHER *EVP_get_cipherbyname(const char *name);
35 #define EVP_get_cipherbynid(a) EVP_get_cipherbyname(OBJ_nid2sn(a)) 47 #define EVP_get_cipherbynid(a) EVP_get_cipherbyname(OBJ_nid2sn(a))
@@ -38,15 +50,21 @@ EVP_EncryptInit, EVP_EncryptUpdate, EVP_EncryptFinal - EVP cipher routines
38 #define EVP_CIPHER_nid(e) ((e)->nid) 50 #define EVP_CIPHER_nid(e) ((e)->nid)
39 #define EVP_CIPHER_block_size(e) ((e)->block_size) 51 #define EVP_CIPHER_block_size(e) ((e)->block_size)
40 #define EVP_CIPHER_key_length(e) ((e)->key_len) 52 #define EVP_CIPHER_key_length(e) ((e)->key_len)
41 #define EVP_CIPHER_iv_length(e) ((e)->iv_len) 53 #define EVP_CIPHER_iv_length(e) ((e)->iv_len)
42 54 #define EVP_CIPHER_flags(e) ((e)->flags)
55 #define EVP_CIPHER_mode(e) ((e)->flags) & EVP_CIPH_MODE)
43 int EVP_CIPHER_type(const EVP_CIPHER *ctx); 56 int EVP_CIPHER_type(const EVP_CIPHER *ctx);
57
44 #define EVP_CIPHER_CTX_cipher(e) ((e)->cipher) 58 #define EVP_CIPHER_CTX_cipher(e) ((e)->cipher)
45 #define EVP_CIPHER_CTX_nid(e) ((e)->cipher->nid) 59 #define EVP_CIPHER_CTX_nid(e) ((e)->cipher->nid)
46 #define EVP_CIPHER_CTX_block_size(e) ((e)->cipher->block_size) 60 #define EVP_CIPHER_CTX_block_size(e) ((e)->cipher->block_size)
47 #define EVP_CIPHER_CTX_key_length(e) ((e)->cipher->key_len) 61 #define EVP_CIPHER_CTX_key_length(e) ((e)->key_len)
48 #define EVP_CIPHER_CTX_iv_length(e) ((e)->cipher->iv_len) 62 #define EVP_CIPHER_CTX_iv_length(e) ((e)->cipher->iv_len)
63 #define EVP_CIPHER_CTX_get_app_data(e) ((e)->app_data)
64 #define EVP_CIPHER_CTX_set_app_data(e,d) ((e)->app_data=(char *)(d))
49 #define EVP_CIPHER_CTX_type(c) EVP_CIPHER_type(EVP_CIPHER_CTX_cipher(c)) 65 #define EVP_CIPHER_CTX_type(c) EVP_CIPHER_type(EVP_CIPHER_CTX_cipher(c))
66 #define EVP_CIPHER_CTX_flags(e) ((e)->cipher->flags)
67 #define EVP_CIPHER_CTX_mode(e) ((e)->cipher->flags & EVP_CIPH_MODE)
50 68
51 int EVP_CIPHER_param_to_asn1(EVP_CIPHER_CTX *c, ASN1_TYPE *type); 69 int EVP_CIPHER_param_to_asn1(EVP_CIPHER_CTX *c, ASN1_TYPE *type);
52 int EVP_CIPHER_asn1_to_param(EVP_CIPHER_CTX *c, ASN1_TYPE *type); 70 int EVP_CIPHER_asn1_to_param(EVP_CIPHER_CTX *c, ASN1_TYPE *type);
@@ -56,16 +74,14 @@ EVP_EncryptInit, EVP_EncryptUpdate, EVP_EncryptFinal - EVP cipher routines
56The EVP cipher routines are a high level interface to certain 74The EVP cipher routines are a high level interface to certain
57symmetric ciphers. 75symmetric ciphers.
58 76
59EVP_EncryptInit() initialises a cipher context B<ctx> for encryption 77EVP_EncryptInit() initializes a cipher context B<ctx> for encryption
60with cipher B<type>. B<type> is normally supplied by a function such 78with cipher B<type>. B<type> is normally supplied by a function such
61as EVP_des_cbc() . B<key> is the symmetric key to use and B<iv> is the 79as EVP_des_cbc() . B<key> is the symmetric key to use and B<iv> is the
62IV to use (if necessary), the actual number of bytes used for the 80IV to use (if necessary), the actual number of bytes used for the
63key and IV depends on the cipher. It is possible to set all parameters 81key and IV depends on the cipher. It is possible to set all parameters
64to NULL except B<type> in an initial call and supply the remaining 82to NULL except B<type> in an initial call and supply the remaining
65parameters in subsequent calls. This is normally done when the 83parameters in subsequent calls, all of which have B<type> set to NULL.
66EVP_CIPHER_asn1_to_param() function is called to set the cipher 84This is done when the default cipher parameters are not appropriate.
67parameters from an ASN1 AlgorithmIdentifier and the key from a
68different source.
69 85
70EVP_EncryptUpdate() encrypts B<inl> bytes from the buffer B<in> and 86EVP_EncryptUpdate() encrypts B<inl> bytes from the buffer B<in> and
71writes the encrypted version to B<out>. This function can be called 87writes the encrypted version to B<out>. This function can be called
@@ -93,7 +109,8 @@ cipher block size is 1 in which case B<inl> bytes is sufficient.
93EVP_CipherInit(), EVP_CipherUpdate() and EVP_CipherFinal() are functions 109EVP_CipherInit(), EVP_CipherUpdate() and EVP_CipherFinal() are functions
94that can be used for decryption or encryption. The operation performed 110that can be used for decryption or encryption. The operation performed
95depends on the value of the B<enc> parameter. It should be set to 1 for 111depends on the value of the B<enc> parameter. It should be set to 1 for
96encryption and 0 for decryption. 112encryption, 0 for decryption and -1 to leave the value unchanged (the
113actual value of 'enc' being supplied in a previous call).
97 114
98EVP_CIPHER_CTX_cleanup() clears all information from a cipher context. 115EVP_CIPHER_CTX_cleanup() clears all information from a cipher context.
99It should be called after all operations using a cipher are complete 116It should be called after all operations using a cipher are complete
@@ -111,7 +128,13 @@ IDENTIFIER.
111EVP_CIPHER_key_length() and EVP_CIPHER_CTX_key_length() return the key 128EVP_CIPHER_key_length() and EVP_CIPHER_CTX_key_length() return the key
112length of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX> 129length of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX>
113structure. The constant B<EVP_MAX_KEY_LENGTH> is the maximum key length 130structure. The constant B<EVP_MAX_KEY_LENGTH> is the maximum key length
114for all ciphers. 131for all ciphers. Note: although EVP_CIPHER_key_length() is fixed for a
132given cipher, the value of EVP_CIPHER_CTX_key_length() may be different
133for variable key length ciphers.
134
135EVP_CIPHER_CTX_set_key_length() sets the key length of the cipher ctx.
136If the cipher is a fixed length cipher then attempting to set the key
137length to any value other than the fixed value is an error.
115 138
116EVP_CIPHER_iv_length() and EVP_CIPHER_CTX_iv_length() return the IV 139EVP_CIPHER_iv_length() and EVP_CIPHER_CTX_iv_length() return the IV
117length of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX>. 140length of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX>.
@@ -133,6 +156,11 @@ B<NID_undef>.
133EVP_CIPHER_CTX_cipher() returns the B<EVP_CIPHER> structure when passed 156EVP_CIPHER_CTX_cipher() returns the B<EVP_CIPHER> structure when passed
134an B<EVP_CIPHER_CTX> structure. 157an B<EVP_CIPHER_CTX> structure.
135 158
159EVP_CIPHER_mode() and EVP_CIPHER_CTX_mode() return the block cipher mode:
160EVP_CIPH_ECB_MODE, EVP_CIPH_CBC_MODE, EVP_CIPH_CFB_MODE or
161EVP_CIPH_OFB_MODE. If the cipher is a stream cipher then
162EVP_CIPH_STREAM_CIPHER is returned.
163
136EVP_CIPHER_param_to_asn1() sets the AlgorithmIdentifier "parameter" based 164EVP_CIPHER_param_to_asn1() sets the AlgorithmIdentifier "parameter" based
137on the passed cipher. This will typically include any parameters and an 165on the passed cipher. This will typically include any parameters and an
138IV. The cipher IV (if any) must be set when this call is made. This call 166IV. The cipher IV (if any) must be set when this call is made. This call
@@ -149,21 +177,24 @@ key set to NULL, EVP_CIPHER_asn1_to_param() will be called and finally
149EVP_CipherInit() again with all parameters except the key set to NULL. It is 177EVP_CipherInit() again with all parameters except the key set to NULL. It is
150possible for this function to fail if the cipher does not have any ASN1 support 178possible for this function to fail if the cipher does not have any ASN1 support
151or the parameters cannot be set (for example the RC2 effective key length 179or the parameters cannot be set (for example the RC2 effective key length
152does not have an B<EVP_CIPHER> structure). 180is not supported.
181
182EVP_CIPHER_CTX_ctrl() allows various cipher specific parameters to be determined
183and set. Currently only the RC2 effective key length and the number of rounds of
184RC5 can be set.
153 185
154=head1 RETURN VALUES 186=head1 RETURN VALUES
155 187
156EVP_EncryptInit(), EVP_EncryptUpdate() and EVP_EncryptFinal() do not return 188EVP_EncryptInit(), EVP_EncryptUpdate() and EVP_EncryptFinal() return 1 for success
157values. 189and 0 for failure.
158 190
159EVP_DecryptInit() and EVP_DecryptUpdate() do not return values. 191EVP_DecryptInit() and EVP_DecryptUpdate() return 1 for success and 0 for failure.
160EVP_DecryptFinal() returns 0 if the decrypt failed or 1 for success. 192EVP_DecryptFinal() returns 0 if the decrypt failed or 1 for success.
161 193
162EVP_CipherInit() and EVP_CipherUpdate() do not return values. 194EVP_CipherInit() and EVP_CipherUpdate() return 1 for success and 0 for failure.
163EVP_CipherFinal() returns 1 for a decryption failure or 1 for success, if 195EVP_CipherFinal() returns 1 for a decryption failure or 1 for success.
164the operation is encryption then it always returns 1.
165 196
166EVP_CIPHER_CTX_cleanup() does not return a value. 197EVP_CIPHER_CTX_cleanup() returns 1 for success and 0 for failure.
167 198
168EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj() 199EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj()
169return an B<EVP_CIPHER> structure or NULL on error. 200return an B<EVP_CIPHER> structure or NULL on error.
@@ -187,6 +218,75 @@ EVP_CIPHER_CTX_cipher() returns an B<EVP_CIPHER> structure.
187EVP_CIPHER_param_to_asn1() and EVP_CIPHER_asn1_to_param() return 1 for 218EVP_CIPHER_param_to_asn1() and EVP_CIPHER_asn1_to_param() return 1 for
188success or zero for failure. 219success or zero for failure.
189 220
221=head1 CIPHER LISTING
222
223All algorithms have a fixed key length unless otherwise stated.
224
225=over 4
226
227=item EVP_enc_null()
228
229Null cipher: does nothing.
230
231=item EVP_des_cbc(void), EVP_des_ecb(void), EVP_des_cfb(void), EVP_des_ofb(void)
232
233DES in CBC, ECB, CFB and OFB modes respectively.
234
235=item EVP_des_ede_cbc(void), EVP_des_ede(), EVP_des_ede_ofb(void), EVP_des_ede_cfb(void)
236
237Two key triple DES in CBC, ECB, CFB and OFB modes respectively.
238
239=item EVP_des_ede3_cbc(void), EVP_des_ede3(), EVP_des_ede3_ofb(void), EVP_des_ede3_cfb(void)
240
241Three key triple DES in CBC, ECB, CFB and OFB modes respectively.
242
243=item EVP_desx_cbc(void)
244
245DESX algorithm in CBC mode.
246
247=item EVP_rc4(void)
248
249RC4 stream cipher. This is a variable key length cipher with default key length 128 bits.
250
251=item EVP_rc4_40(void)
252
253RC4 stream cipher with 40 bit key length. This is obsolete and new code should use EVP_rc4()
254and the EVP_CIPHER_CTX_set_key_length() function.
255
256=item EVP_idea_cbc() EVP_idea_ecb(void), EVP_idea_cfb(void), EVP_idea_ofb(void), EVP_idea_cbc(void)
257
258IDEA encryption algorithm in CBC, ECB, CFB and OFB modes respectively.
259
260=item EVP_rc2_cbc(void), EVP_rc2_ecb(void), EVP_rc2_cfb(void), EVP_rc2_ofb(void)
261
262RC2 encryption algorithm in CBC, ECB, CFB and OFB modes respectively. This is a variable key
263length cipher with an additional parameter called "effective key bits" or "effective key length".
264By default both are set to 128 bits.
265
266=item EVP_rc2_40_cbc(void), EVP_rc2_64_cbc(void)
267
268RC2 algorithm in CBC mode with a default key length and effective key length of 40 and 64 bits.
269These are obsolete and new code should use EVP_rc2_cbc(), EVP_CIPHER_CTX_set_key_length() and
270EVP_CIPHER_CTX_ctrl() to set the key length and effective key length.
271
272=item EVP_bf_cbc(void), EVP_bf_ecb(void), EVP_bf_cfb(void), EVP_bf_ofb(void);
273
274Blowfish encryption algorithm in CBC, ECB, CFB and OFB modes respectively. This is a variable key
275length cipher.
276
277=item EVP_cast5_cbc(void), EVP_cast5_ecb(void), EVP_cast5_cfb(void), EVP_cast5_ofb(void)
278
279CAST encryption algorithm in CBC, ECB, CFB and OFB modes respectively. This is a variable key
280length cipher.
281
282=item EVP_rc5_32_12_16_cbc(void), EVP_rc5_32_12_16_ecb(void), EVP_rc5_32_12_16_cfb(void), EVP_rc5_32_12_16_ofb(void)
283
284RC5 encryption algorithm in CBC, ECB, CFB and OFB modes respectively. This is a variable key length
285cipher with an additional "number of rounds" parameter. By default the key length is set to 128
286bits and 12 rounds.
287
288=back
289
190=head1 NOTES 290=head1 NOTES
191 291
192Where possible the B<EVP> interface to symmetric ciphers should be used in 292Where possible the B<EVP> interface to symmetric ciphers should be used in
@@ -206,14 +306,49 @@ test that the input data or key is correct. A random block has better than
2061 in 256 chance of being of the correct format and problems with the 3061 in 256 chance of being of the correct format and problems with the
207input data earlier on will not produce a final decrypt error. 307input data earlier on will not produce a final decrypt error.
208 308
309The functions EVP_EncryptInit(), EVP_EncryptUpdate(), EVP_EncryptFinal(),
310EVP_DecryptInit(), EVP_DecryptUpdate(), EVP_CipherInit() and EVP_CipherUpdate()
311and EVP_CIPHER_CTX_cleanup() did not return errors in OpenSSL version 0.9.5a or
312earlier. Software only versions of encryption algorithms will never return
313error codes for these functions, unless there is a programming error (for example
314and attempt to set the key before the cipher is set in EVP_EncryptInit() ).
315
209=head1 BUGS 316=head1 BUGS
210 317
211The current B<EVP> cipher interface is not as flexible as it should be. Only 318For RC5 the number of rounds can currently only be set to 8, 12 or 16. This is
212certain "spot" encryption algorithms can be used for ciphers which have various 319a limitation of the current RC5 code rather than the EVP interface.
213parameters associated with them (RC2, RC5 for example) this is inadequate. 320
321It should be possible to disable PKCS padding: currently it isn't.
322
323EVP_MAX_KEY_LENGTH and EVP_MAX_IV_LENGTH only refer to the internal ciphers with
324default key lengths. If custom ciphers exceed these values the results are
325unpredictable. This is because it has become standard practice to define a
326generic key as a fixed unsigned char array containing EVP_MAX_KEY_LENGTH bytes.
327
328The ASN1 code is incomplete (and sometimes inaccurate) it has only been tested
329for certain common S/MIME ciphers (RC2, DES, triple DES) in CBC mode.
330
331=head1 EXAMPLES
332
333Get the number of rounds used in RC5:
334
335 int nrounds;
336 EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GET_RC5_ROUNDS, 0, &i);
337
338Get the RC2 effective key length:
339
340 int key_bits;
341 EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GET_RC2_KEY_BITS, 0, &i);
342
343Set the number of rounds used in RC5:
344
345 int nrounds;
346 EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_SET_RC5_ROUNDS, i, NULL);
347
348Set the number of rounds used in RC2:
214 349
215Several of the functions do not return error codes because the software versions 350 int nrounds;
216can never fail. This is not true of hardware versions. 351 EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_SET_RC2_KEY_BITS, i, NULL);
217 352
218=head1 SEE ALSO 353=head1 SEE ALSO
219 354