diff options
Diffstat (limited to 'botan/src/kdf/ssl_prf/prf_ssl3.cpp')
-rw-r--r-- | botan/src/kdf/ssl_prf/prf_ssl3.cpp | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/botan/src/kdf/ssl_prf/prf_ssl3.cpp b/botan/src/kdf/ssl_prf/prf_ssl3.cpp new file mode 100644 index 0000000..2b67644 --- /dev/null +++ b/botan/src/kdf/ssl_prf/prf_ssl3.cpp @@ -0,0 +1,76 @@ +/* +* SSLv3 PRF +* (C) 2004-2006 Jack Lloyd +* +* Distributed under the terms of the Botan license +*/ + +#include <botan/prf_ssl3.h> +#include <botan/symkey.h> +#include <botan/exceptn.h> +#include <botan/sha160.h> +#include <botan/md5.h> +#include <memory> + +namespace Botan { + +namespace { + +/* +* Return the next inner hash +*/ +OctetString next_hash(u32bit where, u32bit want, + HashFunction& md5, HashFunction& sha1, + const byte secret[], u32bit secret_len, + const byte seed[], u32bit seed_len) + { + if(want > md5.OUTPUT_LENGTH) + throw Internal_Error("SSL3_PRF:next_hash: want is too big"); + + const byte ASCII_A_CHAR = 0x41; + + for(u32bit j = 0; j != where + 1; j++) + sha1.update(ASCII_A_CHAR + where); + sha1.update(secret, secret_len); + sha1.update(seed, seed_len); + SecureVector<byte> sha1_hash = sha1.final(); + + md5.update(secret, secret_len); + md5.update(sha1_hash); + SecureVector<byte> md5_hash = md5.final(); + + return OctetString(md5_hash, want); + } + +} + +/* +* SSL3 PRF +*/ +SecureVector<byte> SSL3_PRF::derive(u32bit key_len, + const byte secret[], u32bit secret_len, + const byte seed[], u32bit seed_len) const + { + if(key_len > 416) + throw Internal_Error("SSL3_PRF: Requested key length is too large"); + + MD5 md5; + SHA_160 sha1; + + OctetString output; + + int counter = 0; + while(key_len) + { + const u32bit produce = std::min(key_len, md5.OUTPUT_LENGTH); + + output = output + next_hash(counter++, produce, md5, sha1, + secret, secret_len, seed, seed_len); + + key_len -= produce; + } + + return output.bits_of(); + } + +} |