Update build for OpenSSL-0.9.8j upgrade.
[dragonfly.git] / secure / lib / libcrypto / man / EVP_EncryptInit.3
CommitLineData
e257b235 1.\" Automatically generated by Pod::Man 2.16 (Pod::Simple 3.05)
8b0cefbb
JR
2.\"
3.\" Standard preamble:
4.\" ========================================================================
5.de Sh \" Subsection heading
984263bc
MD
6.br
7.if t .Sp
8.ne 5
9.PP
10\fB\\$1\fR
11.PP
12..
8b0cefbb 13.de Sp \" Vertical space (when we can't use .PP)
984263bc
MD
14.if t .sp .5v
15.if n .sp
16..
8b0cefbb 17.de Vb \" Begin verbatim text
984263bc
MD
18.ft CW
19.nf
20.ne \\$1
21..
8b0cefbb 22.de Ve \" End verbatim text
984263bc 23.ft R
984263bc
MD
24.fi
25..
8b0cefbb
JR
26.\" Set up some character translations and predefined strings. \*(-- will
27.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
e257b235
PA
28.\" double quote, and \*(R" will give a right double quote. \*(C+ will
29.\" give a nicer C++. Capital omega is used to do unbreakable dashes and
30.\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
31.\" nothing in troff, for use with C<>.
32.tr \(*W-
8b0cefbb 33.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
984263bc 34.ie n \{\
8b0cefbb
JR
35. ds -- \(*W-
36. ds PI pi
37. if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
38. if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch
39. ds L" ""
40. ds R" ""
41. ds C` ""
42. ds C' ""
984263bc
MD
43'br\}
44.el\{\
8b0cefbb
JR
45. ds -- \|\(em\|
46. ds PI \(*p
47. ds L" ``
48. ds R" ''
984263bc 49'br\}
8b0cefbb 50.\"
e257b235
PA
51.\" Escape single quotes in literal strings from groff's Unicode transform.
52.ie \n(.g .ds Aq \(aq
53.el .ds Aq '
54.\"
8b0cefbb
JR
55.\" If the F register is turned on, we'll generate index entries on stderr for
56.\" titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and index
57.\" entries marked with X<> in POD. Of course, you'll have to process the
58.\" output yourself in some meaningful fashion.
e257b235 59.ie \nF \{\
8b0cefbb
JR
60. de IX
61. tm Index:\\$1\t\\n%\t"\\$2"
984263bc 62..
8b0cefbb
JR
63. nr % 0
64. rr F
984263bc 65.\}
e257b235
PA
66.el \{\
67. de IX
68..
69.\}
aac4ff6f 70.\"
8b0cefbb
JR
71.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
72.\" Fear. Run. Save yourself. No user-serviceable parts.
73. \" fudge factors for nroff and troff
984263bc 74.if n \{\
8b0cefbb
JR
75. ds #H 0
76. ds #V .8m
77. ds #F .3m
78. ds #[ \f1
79. ds #] \fP
984263bc
MD
80.\}
81.if t \{\
8b0cefbb
JR
82. ds #H ((1u-(\\\\n(.fu%2u))*.13m)
83. ds #V .6m
84. ds #F 0
85. ds #[ \&
86. ds #] \&
984263bc 87.\}
8b0cefbb 88. \" simple accents for nroff and troff
984263bc 89.if n \{\
8b0cefbb
JR
90. ds ' \&
91. ds ` \&
92. ds ^ \&
93. ds , \&
94. ds ~ ~
95. ds /
984263bc
MD
96.\}
97.if t \{\
8b0cefbb
JR
98. ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
99. ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
100. ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
101. ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
102. ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
103. ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
984263bc 104.\}
8b0cefbb 105. \" troff and (daisy-wheel) nroff accents
984263bc
MD
106.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
107.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
108.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
109.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
110.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
111.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
112.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
113.ds ae a\h'-(\w'a'u*4/10)'e
114.ds Ae A\h'-(\w'A'u*4/10)'E
8b0cefbb 115. \" corrections for vroff
984263bc
MD
116.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
117.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
8b0cefbb 118. \" for low resolution devices (crt and lpr)
984263bc
MD
119.if \n(.H>23 .if \n(.V>19 \
120\{\
8b0cefbb
JR
121. ds : e
122. ds 8 ss
123. ds o a
124. ds d- d\h'-1'\(ga
125. ds D- D\h'-1'\(hy
126. ds th \o'bp'
127. ds Th \o'LP'
128. ds ae ae
129. ds Ae AE
984263bc
MD
130.\}
131.rm #[ #] #H #V #F C
8b0cefbb
JR
132.\" ========================================================================
133.\"
134.IX Title "EVP_EncryptInit 3"
e257b235
PA
135.TH EVP_EncryptInit 3 "2009-01-11" "0.9.8j" "OpenSSL"
136.\" For nroff, turn off justification. Always turn off hyphenation; it makes
137.\" way too many mistakes in technical documents.
138.if n .ad l
139.nh
984263bc
MD
140.SH "NAME"
141EVP_CIPHER_CTX_init, EVP_EncryptInit_ex, EVP_EncryptUpdate,
142EVP_EncryptFinal_ex, EVP_DecryptInit_ex, EVP_DecryptUpdate,
143EVP_DecryptFinal_ex, EVP_CipherInit_ex, EVP_CipherUpdate,
144EVP_CipherFinal_ex, EVP_CIPHER_CTX_set_key_length,
145EVP_CIPHER_CTX_ctrl, EVP_CIPHER_CTX_cleanup, EVP_EncryptInit,
146EVP_EncryptFinal, EVP_DecryptInit, EVP_DecryptFinal,
147EVP_CipherInit, EVP_CipherFinal, EVP_get_cipherbyname,
148EVP_get_cipherbynid, EVP_get_cipherbyobj, EVP_CIPHER_nid,
149EVP_CIPHER_block_size, EVP_CIPHER_key_length, EVP_CIPHER_iv_length,
150EVP_CIPHER_flags, EVP_CIPHER_mode, EVP_CIPHER_type, EVP_CIPHER_CTX_cipher,
151EVP_CIPHER_CTX_nid, EVP_CIPHER_CTX_block_size, EVP_CIPHER_CTX_key_length,
152EVP_CIPHER_CTX_iv_length, EVP_CIPHER_CTX_get_app_data,
153EVP_CIPHER_CTX_set_app_data, EVP_CIPHER_CTX_type, EVP_CIPHER_CTX_flags,
154EVP_CIPHER_CTX_mode, EVP_CIPHER_param_to_asn1, EVP_CIPHER_asn1_to_param,
74dab6c2 155EVP_CIPHER_CTX_set_padding \- EVP cipher routines
984263bc 156.SH "SYNOPSIS"
8b0cefbb 157.IX Header "SYNOPSIS"
984263bc
MD
158.Vb 1
159\& #include <openssl/evp.h>
e257b235 160\&
a561f9ff 161\& void EVP_CIPHER_CTX_init(EVP_CIPHER_CTX *a);
e257b235 162\&
984263bc
MD
163\& int EVP_EncryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
164\& ENGINE *impl, unsigned char *key, unsigned char *iv);
165\& int EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
166\& int *outl, unsigned char *in, int inl);
167\& int EVP_EncryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out,
168\& int *outl);
e257b235 169\&
984263bc
MD
170\& int EVP_DecryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
171\& ENGINE *impl, unsigned char *key, unsigned char *iv);
172\& int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
173\& int *outl, unsigned char *in, int inl);
174\& int EVP_DecryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm,
175\& int *outl);
e257b235 176\&
984263bc
MD
177\& int EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
178\& ENGINE *impl, unsigned char *key, unsigned char *iv, int enc);
179\& int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
180\& int *outl, unsigned char *in, int inl);
181\& int EVP_CipherFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm,
182\& int *outl);
e257b235 183\&
984263bc
MD
184\& int EVP_EncryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
185\& unsigned char *key, unsigned char *iv);
186\& int EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out,
187\& int *outl);
e257b235 188\&
984263bc
MD
189\& int EVP_DecryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
190\& unsigned char *key, unsigned char *iv);
191\& int EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm,
192\& int *outl);
e257b235 193\&
984263bc
MD
194\& int EVP_CipherInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
195\& unsigned char *key, unsigned char *iv, int enc);
196\& int EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm,
197\& int *outl);
e257b235 198\&
984263bc
MD
199\& int EVP_CIPHER_CTX_set_padding(EVP_CIPHER_CTX *x, int padding);
200\& int EVP_CIPHER_CTX_set_key_length(EVP_CIPHER_CTX *x, int keylen);
201\& int EVP_CIPHER_CTX_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg, void *ptr);
202\& int EVP_CIPHER_CTX_cleanup(EVP_CIPHER_CTX *a);
e257b235 203\&
984263bc
MD
204\& const EVP_CIPHER *EVP_get_cipherbyname(const char *name);
205\& #define EVP_get_cipherbynid(a) EVP_get_cipherbyname(OBJ_nid2sn(a))
206\& #define EVP_get_cipherbyobj(a) EVP_get_cipherbynid(OBJ_obj2nid(a))
e257b235
PA
207\&
208\& #define EVP_CIPHER_nid(e) ((e)\->nid)
209\& #define EVP_CIPHER_block_size(e) ((e)\->block_size)
210\& #define EVP_CIPHER_key_length(e) ((e)\->key_len)
211\& #define EVP_CIPHER_iv_length(e) ((e)\->iv_len)
212\& #define EVP_CIPHER_flags(e) ((e)\->flags)
213\& #define EVP_CIPHER_mode(e) ((e)\->flags) & EVP_CIPH_MODE)
984263bc 214\& int EVP_CIPHER_type(const EVP_CIPHER *ctx);
e257b235
PA
215\&
216\& #define EVP_CIPHER_CTX_cipher(e) ((e)\->cipher)
217\& #define EVP_CIPHER_CTX_nid(e) ((e)\->cipher\->nid)
218\& #define EVP_CIPHER_CTX_block_size(e) ((e)\->cipher\->block_size)
219\& #define EVP_CIPHER_CTX_key_length(e) ((e)\->key_len)
220\& #define EVP_CIPHER_CTX_iv_length(e) ((e)\->cipher\->iv_len)
221\& #define EVP_CIPHER_CTX_get_app_data(e) ((e)\->app_data)
222\& #define EVP_CIPHER_CTX_set_app_data(e,d) ((e)\->app_data=(char *)(d))
984263bc 223\& #define EVP_CIPHER_CTX_type(c) EVP_CIPHER_type(EVP_CIPHER_CTX_cipher(c))
e257b235
PA
224\& #define EVP_CIPHER_CTX_flags(e) ((e)\->cipher\->flags)
225\& #define EVP_CIPHER_CTX_mode(e) ((e)\->cipher\->flags & EVP_CIPH_MODE)
226\&
984263bc
MD
227\& int EVP_CIPHER_param_to_asn1(EVP_CIPHER_CTX *c, ASN1_TYPE *type);
228\& int EVP_CIPHER_asn1_to_param(EVP_CIPHER_CTX *c, ASN1_TYPE *type);
229.Ve
230.SH "DESCRIPTION"
8b0cefbb
JR
231.IX Header "DESCRIPTION"
232The \s-1EVP\s0 cipher routines are a high level interface to certain
984263bc
MD
233symmetric ciphers.
234.PP
8b0cefbb 235\&\fIEVP_CIPHER_CTX_init()\fR initializes cipher contex \fBctx\fR.
984263bc 236.PP
8b0cefbb
JR
237\&\fIEVP_EncryptInit_ex()\fR sets up cipher context \fBctx\fR for encryption
238with cipher \fBtype\fR from \s-1ENGINE\s0 \fBimpl\fR. \fBctx\fR must be initialized
984263bc 239before calling this function. \fBtype\fR is normally supplied
8b0cefbb 240by a function such as \fIEVP_des_cbc()\fR. If \fBimpl\fR is \s-1NULL\s0 then the
984263bc 241default implementation is used. \fBkey\fR is the symmetric key to use
8b0cefbb
JR
242and \fBiv\fR is the \s-1IV\s0 to use (if necessary), the actual number of bytes
243used for the key and \s-1IV\s0 depends on the cipher. It is possible to set
244all parameters to \s-1NULL\s0 except \fBtype\fR in an initial call and supply
984263bc 245the remaining parameters in subsequent calls, all of which have \fBtype\fR
8b0cefbb 246set to \s-1NULL\s0. This is done when the default cipher parameters are not
984263bc
MD
247appropriate.
248.PP
8b0cefbb 249\&\fIEVP_EncryptUpdate()\fR encrypts \fBinl\fR bytes from the buffer \fBin\fR and
984263bc
MD
250writes the encrypted version to \fBout\fR. This function can be called
251multiple times to encrypt successive blocks of data. The amount
252of data written depends on the block alignment of the encrypted data:
253as a result the amount of data written may be anything from zero bytes
254to (inl + cipher_block_size \- 1) so \fBoutl\fR should contain sufficient
255room. The actual number of bytes written is placed in \fBoutl\fR.
256.PP
257If padding is enabled (the default) then \fIEVP_EncryptFinal_ex()\fR encrypts
258the \*(L"final\*(R" data, that is any data that remains in a partial block.
8b0cefbb 259It uses standard block padding (aka \s-1PKCS\s0 padding). The encrypted
984263bc
MD
260final data is written to \fBout\fR which should have sufficient space for
261one cipher block. The number of bytes written is placed in \fBoutl\fR. After
262this function is called the encryption operation is finished and no further
263calls to \fIEVP_EncryptUpdate()\fR should be made.
264.PP
265If padding is disabled then \fIEVP_EncryptFinal_ex()\fR will not encrypt any more
266data and it will return an error if any data remains in a partial block:
e257b235 267that is if the total data length is not a multiple of the block size.
984263bc 268.PP
8b0cefbb 269\&\fIEVP_DecryptInit_ex()\fR, \fIEVP_DecryptUpdate()\fR and \fIEVP_DecryptFinal_ex()\fR are the
984263bc
MD
270corresponding decryption operations. \fIEVP_DecryptFinal()\fR will return an
271error code if padding is enabled and the final block is not correctly
272formatted. The parameters and restrictions are identical to the encryption
273operations except that if padding is enabled the decrypted data buffer \fBout\fR
274passed to \fIEVP_DecryptUpdate()\fR should have sufficient room for
275(\fBinl\fR + cipher_block_size) bytes unless the cipher block size is 1 in
276which case \fBinl\fR bytes is sufficient.
277.PP
8b0cefbb 278\&\fIEVP_CipherInit_ex()\fR, \fIEVP_CipherUpdate()\fR and \fIEVP_CipherFinal_ex()\fR are
984263bc
MD
279functions that can be used for decryption or encryption. The operation
280performed depends on the value of the \fBenc\fR parameter. It should be set
281to 1 for encryption, 0 for decryption and \-1 to leave the value unchanged
8b0cefbb 282(the actual value of 'enc' being supplied in a previous call).
984263bc 283.PP
8b0cefbb 284\&\fIEVP_CIPHER_CTX_cleanup()\fR clears all information from a cipher context
984263bc
MD
285and free up any allocated memory associate with it. It should be called
286after all operations using a cipher are complete so sensitive information
287does not remain in memory.
288.PP
8b0cefbb 289\&\fIEVP_EncryptInit()\fR, \fIEVP_DecryptInit()\fR and \fIEVP_CipherInit()\fR behave in a
984263bc 290similar way to \fIEVP_EncryptInit_ex()\fR, EVP_DecryptInit_ex and
8b0cefbb 291\&\fIEVP_CipherInit_ex()\fR except the \fBctx\fR paramter does not need to be
984263bc
MD
292initialized and they always use the default cipher implementation.
293.PP
8b0cefbb 294\&\fIEVP_EncryptFinal()\fR, \fIEVP_DecryptFinal()\fR and \fIEVP_CipherFinal()\fR behave in a
984263bc 295similar way to \fIEVP_EncryptFinal_ex()\fR, \fIEVP_DecryptFinal_ex()\fR and
8b0cefbb 296\&\fIEVP_CipherFinal_ex()\fR except \fBctx\fR is automatically cleaned up
984263bc
MD
297after the call.
298.PP
8b0cefbb
JR
299\&\fIEVP_get_cipherbyname()\fR, \fIEVP_get_cipherbynid()\fR and \fIEVP_get_cipherbyobj()\fR
300return an \s-1EVP_CIPHER\s0 structure when passed a cipher name, a \s-1NID\s0 or an
301\&\s-1ASN1_OBJECT\s0 structure.
984263bc 302.PP
8b0cefbb
JR
303\&\fIEVP_CIPHER_nid()\fR and \fIEVP_CIPHER_CTX_nid()\fR return the \s-1NID\s0 of a cipher when
304passed an \fB\s-1EVP_CIPHER\s0\fR or \fB\s-1EVP_CIPHER_CTX\s0\fR structure. The actual \s-1NID\s0
305value is an internal value which may not have a corresponding \s-1OBJECT\s0
306\&\s-1IDENTIFIER\s0.
984263bc 307.PP
8b0cefbb 308\&\fIEVP_CIPHER_CTX_set_padding()\fR enables or disables padding. By default
984263bc
MD
309encryption operations are padded using standard block padding and the
310padding is checked and removed when decrypting. If the \fBpad\fR parameter
311is zero then no padding is performed, the total amount of data encrypted
312or decrypted must then be a multiple of the block size or an error will
313occur.
314.PP
8b0cefbb
JR
315\&\fIEVP_CIPHER_key_length()\fR and \fIEVP_CIPHER_CTX_key_length()\fR return the key
316length of a cipher when passed an \fB\s-1EVP_CIPHER\s0\fR or \fB\s-1EVP_CIPHER_CTX\s0\fR
317structure. The constant \fB\s-1EVP_MAX_KEY_LENGTH\s0\fR is the maximum key length
984263bc
MD
318for all ciphers. Note: although \fIEVP_CIPHER_key_length()\fR is fixed for a
319given cipher, the value of \fIEVP_CIPHER_CTX_key_length()\fR may be different
320for variable key length ciphers.
321.PP
8b0cefbb 322\&\fIEVP_CIPHER_CTX_set_key_length()\fR sets the key length of the cipher ctx.
984263bc
MD
323If the cipher is a fixed length cipher then attempting to set the key
324length to any value other than the fixed value is an error.
325.PP
8b0cefbb
JR
326\&\fIEVP_CIPHER_iv_length()\fR and \fIEVP_CIPHER_CTX_iv_length()\fR return the \s-1IV\s0
327length of a cipher when passed an \fB\s-1EVP_CIPHER\s0\fR or \fB\s-1EVP_CIPHER_CTX\s0\fR.
328It will return zero if the cipher does not use an \s-1IV\s0. The constant
329\&\fB\s-1EVP_MAX_IV_LENGTH\s0\fR is the maximum \s-1IV\s0 length for all ciphers.
984263bc 330.PP
8b0cefbb
JR
331\&\fIEVP_CIPHER_block_size()\fR and \fIEVP_CIPHER_CTX_block_size()\fR return the block
332size of a cipher when passed an \fB\s-1EVP_CIPHER\s0\fR or \fB\s-1EVP_CIPHER_CTX\s0\fR
333structure. The constant \fB\s-1EVP_MAX_IV_LENGTH\s0\fR is also the maximum block
984263bc
MD
334length for all ciphers.
335.PP
8b0cefbb
JR
336\&\fIEVP_CIPHER_type()\fR and \fIEVP_CIPHER_CTX_type()\fR return the type of the passed
337cipher or context. This \*(L"type\*(R" is the actual \s-1NID\s0 of the cipher \s-1OBJECT\s0
338\&\s-1IDENTIFIER\s0 as such it ignores the cipher parameters and 40 bit \s-1RC2\s0 and
339128 bit \s-1RC2\s0 have the same \s-1NID\s0. If the cipher does not have an object
340identifier or does not have \s-1ASN1\s0 support this function will return
341\&\fBNID_undef\fR.
984263bc 342.PP
8b0cefbb
JR
343\&\fIEVP_CIPHER_CTX_cipher()\fR returns the \fB\s-1EVP_CIPHER\s0\fR structure when passed
344an \fB\s-1EVP_CIPHER_CTX\s0\fR structure.
984263bc 345.PP
8b0cefbb
JR
346\&\fIEVP_CIPHER_mode()\fR and \fIEVP_CIPHER_CTX_mode()\fR return the block cipher mode:
347\&\s-1EVP_CIPH_ECB_MODE\s0, \s-1EVP_CIPH_CBC_MODE\s0, \s-1EVP_CIPH_CFB_MODE\s0 or
348\&\s-1EVP_CIPH_OFB_MODE\s0. If the cipher is a stream cipher then
349\&\s-1EVP_CIPH_STREAM_CIPHER\s0 is returned.
984263bc 350.PP
8b0cefbb 351\&\fIEVP_CIPHER_param_to_asn1()\fR sets the AlgorithmIdentifier \*(L"parameter\*(R" based
984263bc 352on the passed cipher. This will typically include any parameters and an
8b0cefbb 353\&\s-1IV\s0. The cipher \s-1IV\s0 (if any) must be set when this call is made. This call
984263bc 354should be made before the cipher is actually \*(L"used\*(R" (before any
8b0cefbb
JR
355\&\fIEVP_EncryptUpdate()\fR, \fIEVP_DecryptUpdate()\fR calls for example). This function
356may fail if the cipher does not have any \s-1ASN1\s0 support.
984263bc 357.PP
8b0cefbb 358\&\fIEVP_CIPHER_asn1_to_param()\fR sets the cipher parameters based on an \s-1ASN1\s0
984263bc 359AlgorithmIdentifier \*(L"parameter\*(R". The precise effect depends on the cipher
8b0cefbb 360In the case of \s-1RC2\s0, for example, it will set the \s-1IV\s0 and effective key length.
984263bc 361This function should be called after the base cipher type is set but before
8b0cefbb
JR
362the key is set. For example \fIEVP_CipherInit()\fR will be called with the \s-1IV\s0 and
363key set to \s-1NULL\s0, \fIEVP_CIPHER_asn1_to_param()\fR will be called and finally
364\&\fIEVP_CipherInit()\fR again with all parameters except the key set to \s-1NULL\s0. It is
365possible for this function to fail if the cipher does not have any \s-1ASN1\s0 support
366or the parameters cannot be set (for example the \s-1RC2\s0 effective key length
984263bc
MD
367is not supported.
368.PP
8b0cefbb
JR
369\&\fIEVP_CIPHER_CTX_ctrl()\fR allows various cipher specific parameters to be determined
370and set. Currently only the \s-1RC2\s0 effective key length and the number of rounds of
371\&\s-1RC5\s0 can be set.
984263bc 372.SH "RETURN VALUES"
8b0cefbb 373.IX Header "RETURN VALUES"
a561f9ff
SS
374\&\fIEVP_EncryptInit_ex()\fR, \fIEVP_EncryptUpdate()\fR and \fIEVP_EncryptFinal_ex()\fR
375return 1 for success and 0 for failure.
984263bc 376.PP
8b0cefbb
JR
377\&\fIEVP_DecryptInit_ex()\fR and \fIEVP_DecryptUpdate()\fR return 1 for success and 0 for failure.
378\&\fIEVP_DecryptFinal_ex()\fR returns 0 if the decrypt failed or 1 for success.
984263bc 379.PP
8b0cefbb
JR
380\&\fIEVP_CipherInit_ex()\fR and \fIEVP_CipherUpdate()\fR return 1 for success and 0 for failure.
381\&\fIEVP_CipherFinal_ex()\fR returns 0 for a decryption failure or 1 for success.
984263bc 382.PP
8b0cefbb 383\&\fIEVP_CIPHER_CTX_cleanup()\fR returns 1 for success and 0 for failure.
984263bc 384.PP
8b0cefbb
JR
385\&\fIEVP_get_cipherbyname()\fR, \fIEVP_get_cipherbynid()\fR and \fIEVP_get_cipherbyobj()\fR
386return an \fB\s-1EVP_CIPHER\s0\fR structure or \s-1NULL\s0 on error.
984263bc 387.PP
8b0cefbb 388\&\fIEVP_CIPHER_nid()\fR and \fIEVP_CIPHER_CTX_nid()\fR return a \s-1NID\s0.
984263bc 389.PP
8b0cefbb 390\&\fIEVP_CIPHER_block_size()\fR and \fIEVP_CIPHER_CTX_block_size()\fR return the block
984263bc
MD
391size.
392.PP
8b0cefbb 393\&\fIEVP_CIPHER_key_length()\fR and \fIEVP_CIPHER_CTX_key_length()\fR return the key
984263bc
MD
394length.
395.PP
8b0cefbb 396\&\fIEVP_CIPHER_CTX_set_padding()\fR always returns 1.
984263bc 397.PP
8b0cefbb
JR
398\&\fIEVP_CIPHER_iv_length()\fR and \fIEVP_CIPHER_CTX_iv_length()\fR return the \s-1IV\s0
399length or zero if the cipher does not use an \s-1IV\s0.
984263bc 400.PP
8b0cefbb
JR
401\&\fIEVP_CIPHER_type()\fR and \fIEVP_CIPHER_CTX_type()\fR return the \s-1NID\s0 of the cipher's
402\&\s-1OBJECT\s0 \s-1IDENTIFIER\s0 or NID_undef if it has no defined \s-1OBJECT\s0 \s-1IDENTIFIER\s0.
984263bc 403.PP
8b0cefbb 404\&\fIEVP_CIPHER_CTX_cipher()\fR returns an \fB\s-1EVP_CIPHER\s0\fR structure.
984263bc 405.PP
8b0cefbb 406\&\fIEVP_CIPHER_param_to_asn1()\fR and \fIEVP_CIPHER_asn1_to_param()\fR return 1 for
984263bc
MD
407success or zero for failure.
408.SH "CIPHER LISTING"
8b0cefbb 409.IX Header "CIPHER LISTING"
984263bc 410All algorithms have a fixed key length unless otherwise stated.
8b0cefbb
JR
411.IP "\fIEVP_enc_null()\fR" 4
412.IX Item "EVP_enc_null()"
984263bc 413Null cipher: does nothing.
8b0cefbb
JR
414.IP "EVP_des_cbc(void), EVP_des_ecb(void), EVP_des_cfb(void), EVP_des_ofb(void)" 4
415.IX Item "EVP_des_cbc(void), EVP_des_ecb(void), EVP_des_cfb(void), EVP_des_ofb(void)"
e257b235 416\&\s-1DES\s0 in \s-1CBC\s0, \s-1ECB\s0, \s-1CFB\s0 and \s-1OFB\s0 modes respectively.
8b0cefbb
JR
417.IP "EVP_des_ede_cbc(void), \fIEVP_des_ede()\fR, EVP_des_ede_ofb(void), EVP_des_ede_cfb(void)" 4
418.IX Item "EVP_des_ede_cbc(void), EVP_des_ede(), EVP_des_ede_ofb(void), EVP_des_ede_cfb(void)"
984263bc 419Two key triple \s-1DES\s0 in \s-1CBC\s0, \s-1ECB\s0, \s-1CFB\s0 and \s-1OFB\s0 modes respectively.
8b0cefbb
JR
420.IP "EVP_des_ede3_cbc(void), \fIEVP_des_ede3()\fR, EVP_des_ede3_ofb(void), EVP_des_ede3_cfb(void)" 4
421.IX Item "EVP_des_ede3_cbc(void), EVP_des_ede3(), EVP_des_ede3_ofb(void), EVP_des_ede3_cfb(void)"
984263bc 422Three key triple \s-1DES\s0 in \s-1CBC\s0, \s-1ECB\s0, \s-1CFB\s0 and \s-1OFB\s0 modes respectively.
8b0cefbb
JR
423.IP "EVP_desx_cbc(void)" 4
424.IX Item "EVP_desx_cbc(void)"
425\&\s-1DESX\s0 algorithm in \s-1CBC\s0 mode.
426.IP "EVP_rc4(void)" 4
427.IX Item "EVP_rc4(void)"
428\&\s-1RC4\s0 stream cipher. This is a variable key length cipher with default key length 128 bits.
429.IP "EVP_rc4_40(void)" 4
430.IX Item "EVP_rc4_40(void)"
431\&\s-1RC4\s0 stream cipher with 40 bit key length. This is obsolete and new code should use \fIEVP_rc4()\fR
984263bc 432and the \fIEVP_CIPHER_CTX_set_key_length()\fR function.
8b0cefbb
JR
433.IP "\fIEVP_idea_cbc()\fR EVP_idea_ecb(void), EVP_idea_cfb(void), EVP_idea_ofb(void), EVP_idea_cbc(void)" 4
434.IX Item "EVP_idea_cbc() EVP_idea_ecb(void), EVP_idea_cfb(void), EVP_idea_ofb(void), EVP_idea_cbc(void)"
435\&\s-1IDEA\s0 encryption algorithm in \s-1CBC\s0, \s-1ECB\s0, \s-1CFB\s0 and \s-1OFB\s0 modes respectively.
436.IP "EVP_rc2_cbc(void), EVP_rc2_ecb(void), EVP_rc2_cfb(void), EVP_rc2_ofb(void)" 4
437.IX Item "EVP_rc2_cbc(void), EVP_rc2_ecb(void), EVP_rc2_cfb(void), EVP_rc2_ofb(void)"
438\&\s-1RC2\s0 encryption algorithm in \s-1CBC\s0, \s-1ECB\s0, \s-1CFB\s0 and \s-1OFB\s0 modes respectively. This is a variable key
984263bc
MD
439length cipher with an additional parameter called \*(L"effective key bits\*(R" or \*(L"effective key length\*(R".
440By default both are set to 128 bits.
8b0cefbb
JR
441.IP "EVP_rc2_40_cbc(void), EVP_rc2_64_cbc(void)" 4
442.IX Item "EVP_rc2_40_cbc(void), EVP_rc2_64_cbc(void)"
443\&\s-1RC2\s0 algorithm in \s-1CBC\s0 mode with a default key length and effective key length of 40 and 64 bits.
984263bc 444These are obsolete and new code should use \fIEVP_rc2_cbc()\fR, \fIEVP_CIPHER_CTX_set_key_length()\fR and
8b0cefbb
JR
445\&\fIEVP_CIPHER_CTX_ctrl()\fR to set the key length and effective key length.
446.IP "EVP_bf_cbc(void), EVP_bf_ecb(void), EVP_bf_cfb(void), EVP_bf_ofb(void);" 4
447.IX Item "EVP_bf_cbc(void), EVP_bf_ecb(void), EVP_bf_cfb(void), EVP_bf_ofb(void);"
984263bc
MD
448Blowfish encryption algorithm in \s-1CBC\s0, \s-1ECB\s0, \s-1CFB\s0 and \s-1OFB\s0 modes respectively. This is a variable key
449length cipher.
8b0cefbb
JR
450.IP "EVP_cast5_cbc(void), EVP_cast5_ecb(void), EVP_cast5_cfb(void), EVP_cast5_ofb(void)" 4
451.IX Item "EVP_cast5_cbc(void), EVP_cast5_ecb(void), EVP_cast5_cfb(void), EVP_cast5_ofb(void)"
452\&\s-1CAST\s0 encryption algorithm in \s-1CBC\s0, \s-1ECB\s0, \s-1CFB\s0 and \s-1OFB\s0 modes respectively. This is a variable key
984263bc 453length cipher.
8b0cefbb
JR
454.IP "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)" 4
455.IX 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)"
456\&\s-1RC5\s0 encryption algorithm in \s-1CBC\s0, \s-1ECB\s0, \s-1CFB\s0 and \s-1OFB\s0 modes respectively. This is a variable key length
984263bc
MD
457cipher with an additional \*(L"number of rounds\*(R" parameter. By default the key length is set to 128
458bits and 12 rounds.
459.SH "NOTES"
8b0cefbb
JR
460.IX Header "NOTES"
461Where possible the \fB\s-1EVP\s0\fR interface to symmetric ciphers should be used in
984263bc
MD
462preference to the low level interfaces. This is because the code then becomes
463transparent to the cipher used and much more flexible.
464.PP
8b0cefbb 465\&\s-1PKCS\s0 padding works by adding \fBn\fR padding bytes of value \fBn\fR to make the total
984263bc
MD
466length of the encrypted data a multiple of the block size. Padding is always
467added so if the data is already a multiple of the block size \fBn\fR will equal
468the block size. For example if the block size is 8 and 11 bytes are to be
469encrypted then 5 padding bytes of value 5 will be added.
470.PP
471When decrypting the final block is checked to see if it has the correct form.
472.PP
473Although the decryption operation can produce an error if padding is enabled,
474it is not a strong test that the input data or key is correct. A random block
475has better than 1 in 256 chance of being of the correct format and problems with
476the input data earlier on will not produce a final decrypt error.
477.PP
478If padding is disabled then the decryption operation will always succeed if
479the total amount of data decrypted is a multiple of the block size.
480.PP
481The functions \fIEVP_EncryptInit()\fR, \fIEVP_EncryptFinal()\fR, \fIEVP_DecryptInit()\fR,
8b0cefbb 482\&\fIEVP_CipherInit()\fR and \fIEVP_CipherFinal()\fR are obsolete but are retained for
984263bc 483compatibility with existing code. New code should use \fIEVP_EncryptInit_ex()\fR,
8b0cefbb
JR
484\&\fIEVP_EncryptFinal_ex()\fR, \fIEVP_DecryptInit_ex()\fR, \fIEVP_DecryptFinal_ex()\fR,
485\&\fIEVP_CipherInit_ex()\fR and \fIEVP_CipherFinal_ex()\fR because they can reuse an
984263bc
MD
486existing context without allocating and freeing it up on each call.
487.SH "BUGS"
8b0cefbb
JR
488.IX Header "BUGS"
489For \s-1RC5\s0 the number of rounds can currently only be set to 8, 12 or 16. This is
490a limitation of the current \s-1RC5\s0 code rather than the \s-1EVP\s0 interface.
984263bc 491.PP
8b0cefbb 492\&\s-1EVP_MAX_KEY_LENGTH\s0 and \s-1EVP_MAX_IV_LENGTH\s0 only refer to the internal ciphers with
984263bc
MD
493default key lengths. If custom ciphers exceed these values the results are
494unpredictable. This is because it has become standard practice to define a
8b0cefbb 495generic key as a fixed unsigned char array containing \s-1EVP_MAX_KEY_LENGTH\s0 bytes.
984263bc 496.PP
8b0cefbb
JR
497The \s-1ASN1\s0 code is incomplete (and sometimes inaccurate) it has only been tested
498for certain common S/MIME ciphers (\s-1RC2\s0, \s-1DES\s0, triple \s-1DES\s0) in \s-1CBC\s0 mode.
984263bc 499.SH "EXAMPLES"
8b0cefbb
JR
500.IX Header "EXAMPLES"
501Get the number of rounds used in \s-1RC5:\s0
984263bc
MD
502.PP
503.Vb 2
504\& int nrounds;
505\& EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GET_RC5_ROUNDS, 0, &nrounds);
506.Ve
8b0cefbb
JR
507.PP
508Get the \s-1RC2\s0 effective key length:
984263bc
MD
509.PP
510.Vb 2
511\& int key_bits;
512\& EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GET_RC2_KEY_BITS, 0, &key_bits);
513.Ve
8b0cefbb
JR
514.PP
515Set the number of rounds used in \s-1RC5:\s0
984263bc
MD
516.PP
517.Vb 2
518\& int nrounds;
519\& EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_SET_RC5_ROUNDS, nrounds, NULL);
520.Ve
8b0cefbb
JR
521.PP
522Set the effective key length used in \s-1RC2:\s0
984263bc
MD
523.PP
524.Vb 2
525\& int key_bits;
526\& EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_SET_RC2_KEY_BITS, key_bits, NULL);
527.Ve
8b0cefbb 528.PP
984263bc
MD
529Encrypt a string using blowfish:
530.PP
e257b235 531.Vb 10
984263bc
MD
532\& int do_crypt(char *outfile)
533\& {
534\& unsigned char outbuf[1024];
535\& int outlen, tmplen;
e257b235 536\& /* Bogus key and IV: we\*(Aqd normally set these from
984263bc
MD
537\& * another source.
538\& */
539\& unsigned char key[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
540\& unsigned char iv[] = {1,2,3,4,5,6,7,8};
541\& char intext[] = "Some Crypto Text";
542\& EVP_CIPHER_CTX ctx;
543\& FILE *out;
544\& EVP_CIPHER_CTX_init(&ctx);
545\& EVP_EncryptInit_ex(&ctx, EVP_bf_cbc(), NULL, key, iv);
e257b235 546\&
984263bc
MD
547\& if(!EVP_EncryptUpdate(&ctx, outbuf, &outlen, intext, strlen(intext)))
548\& {
549\& /* Error */
550\& return 0;
551\& }
552\& /* Buffer passed to EVP_EncryptFinal() must be after data just
553\& * encrypted to avoid overwriting it.
554\& */
555\& if(!EVP_EncryptFinal_ex(&ctx, outbuf + outlen, &tmplen))
556\& {
557\& /* Error */
558\& return 0;
559\& }
560\& outlen += tmplen;
561\& EVP_CIPHER_CTX_cleanup(&ctx);
562\& /* Need binary mode for fopen because encrypted data is
563\& * binary data. Also cannot use strlen() on it because
564\& * it wont be null terminated and may contain embedded
565\& * nulls.
566\& */
567\& out = fopen(outfile, "wb");
568\& fwrite(outbuf, 1, outlen, out);
569\& fclose(out);
570\& return 1;
571\& }
572.Ve
8b0cefbb 573.PP
984263bc
MD
574The ciphertext from the above example can be decrypted using the \fBopenssl\fR
575utility with the command line:
576.PP
8b0cefbb 577.Vb 1
e257b235 578\& S<openssl bf \-in cipher.bin \-K 000102030405060708090A0B0C0D0E0F \-iv 0102030405060708 \-d>
8b0cefbb
JR
579.Ve
580.PP
581General encryption, decryption function example using \s-1FILE\s0 I/O and \s-1RC2\s0 with an
984263bc
MD
58280 bit key:
583.PP
e257b235 584.Vb 10
984263bc
MD
585\& int do_crypt(FILE *in, FILE *out, int do_encrypt)
586\& {
587\& /* Allow enough space in output buffer for additional block */
588\& inbuf[1024], outbuf[1024 + EVP_MAX_BLOCK_LENGTH];
589\& int inlen, outlen;
e257b235 590\& /* Bogus key and IV: we\*(Aqd normally set these from
984263bc
MD
591\& * another source.
592\& */
593\& unsigned char key[] = "0123456789";
594\& unsigned char iv[] = "12345678";
e257b235 595\& /* Don\*(Aqt set key or IV because we will modify the parameters */
984263bc
MD
596\& EVP_CIPHER_CTX_init(&ctx);
597\& EVP_CipherInit_ex(&ctx, EVP_rc2(), NULL, NULL, NULL, do_encrypt);
598\& EVP_CIPHER_CTX_set_key_length(&ctx, 10);
599\& /* We finished modifying parameters so now we can set key and IV */
600\& EVP_CipherInit_ex(&ctx, NULL, NULL, key, iv, do_encrypt);
e257b235 601\&
984263bc
MD
602\& for(;;)
603\& {
604\& inlen = fread(inbuf, 1, 1024, in);
605\& if(inlen <= 0) break;
606\& if(!EVP_CipherUpdate(&ctx, outbuf, &outlen, inbuf, inlen))
607\& {
608\& /* Error */
a561f9ff 609\& EVP_CIPHER_CTX_cleanup(&ctx);
984263bc
MD
610\& return 0;
611\& }
612\& fwrite(outbuf, 1, outlen, out);
613\& }
614\& if(!EVP_CipherFinal_ex(&ctx, outbuf, &outlen))
615\& {
616\& /* Error */
a561f9ff 617\& EVP_CIPHER_CTX_cleanup(&ctx);
984263bc
MD
618\& return 0;
619\& }
620\& fwrite(outbuf, 1, outlen, out);
e257b235 621\&
984263bc
MD
622\& EVP_CIPHER_CTX_cleanup(&ctx);
623\& return 1;
624\& }
625.Ve
626.SH "SEE ALSO"
74dab6c2 627.IX Header "SEE ALSO"
8b0cefbb
JR
628\&\fIevp\fR\|(3)
629.SH "HISTORY"
74dab6c2 630.IX Header "HISTORY"
8b0cefbb
JR
631\&\fIEVP_CIPHER_CTX_init()\fR, \fIEVP_EncryptInit_ex()\fR, \fIEVP_EncryptFinal_ex()\fR,
632\&\fIEVP_DecryptInit_ex()\fR, \fIEVP_DecryptFinal_ex()\fR, \fIEVP_CipherInit_ex()\fR,
633\&\fIEVP_CipherFinal_ex()\fR and \fIEVP_CIPHER_CTX_set_padding()\fR appeared in
634OpenSSL 0.9.7.