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-rw-r--r--Documentation/crypto/api-intro.txt41
1 files changed, 16 insertions, 25 deletions
diff --git a/Documentation/crypto/api-intro.txt b/Documentation/crypto/api-intro.txt
index a2ac6d294793..8b49302712a8 100644
--- a/Documentation/crypto/api-intro.txt
+++ b/Documentation/crypto/api-intro.txt
@@ -33,9 +33,16 @@ The idea is to make the user interface and algorithm registration API
33very simple, while hiding the core logic from both. Many good ideas 33very simple, while hiding the core logic from both. Many good ideas
34from existing APIs such as Cryptoapi and Nettle have been adapted for this. 34from existing APIs such as Cryptoapi and Nettle have been adapted for this.
35 35
36The API currently supports three types of transforms: Ciphers, Digests and 36The API currently supports five main types of transforms: AEAD (Authenticated
37Compressors. The compression algorithms especially seem to be performing 37Encryption with Associated Data), Block Ciphers, Ciphers, Compressors and
38very well so far. 38Hashes.
39
40Please note that Block Ciphers is somewhat of a misnomer. It is in fact
41meant to support all ciphers including stream ciphers. The difference
42between Block Ciphers and Ciphers is that the latter operates on exactly
43one block while the former can operate on an arbitrary amount of data,
44subject to block size requirements (i.e., non-stream ciphers can only
45process multiples of blocks).
39 46
40Support for hardware crypto devices via an asynchronous interface is 47Support for hardware crypto devices via an asynchronous interface is
41under development. 48under development.
@@ -69,29 +76,12 @@ Here's an example of how to use the API:
69Many real examples are available in the regression test module (tcrypt.c). 76Many real examples are available in the regression test module (tcrypt.c).
70 77
71 78
72CONFIGURATION NOTES
73
74As Triple DES is part of the DES module, for those using modular builds,
75add the following line to /etc/modprobe.conf:
76
77 alias des3_ede des
78
79The Null algorithms reside in the crypto_null module, so these lines
80should also be added:
81
82 alias cipher_null crypto_null
83 alias digest_null crypto_null
84 alias compress_null crypto_null
85
86The SHA384 algorithm shares code within the SHA512 module, so you'll
87also need:
88 alias sha384 sha512
89
90
91DEVELOPER NOTES 79DEVELOPER NOTES
92 80
93Transforms may only be allocated in user context, and cryptographic 81Transforms may only be allocated in user context, and cryptographic
94methods may only be called from softirq and user contexts. 82methods may only be called from softirq and user contexts. For
83transforms with a setkey method it too should only be called from
84user context.
95 85
96When using the API for ciphers, performance will be optimal if each 86When using the API for ciphers, performance will be optimal if each
97scatterlist contains data which is a multiple of the cipher's block 87scatterlist contains data which is a multiple of the cipher's block
@@ -130,8 +120,9 @@ might already be working on.
130BUGS 120BUGS
131 121
132Send bug reports to: 122Send bug reports to:
133Herbert Xu <herbert@gondor.apana.org.au> 123linux-crypto@vger.kernel.org
134Cc: David S. Miller <davem@redhat.com> 124Cc: Herbert Xu <herbert@gondor.apana.org.au>,
125 David S. Miller <davem@redhat.com>
135 126
136 127
137FURTHER INFORMATION 128FURTHER INFORMATION