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ZenUtils:

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* add FRESC encryption
 * clean up code a bit


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@18345 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Maurus Cuelenaere 2008-08-26 13:21:52 +00:00
parent af5f8665e8
commit bea2ab2398
3 changed files with 52 additions and 26 deletions
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16
utils/zenutils/source/shared/updater.cpp
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@ -115,18 +115,18 @@ bool zen::crypt_firmware(const char* key, byte* buffer, size_t len)
return true;
#else
// Determine if the key length is dword aligned.
/* Determine if the key length is dword aligned. */
int keylen = strlen(key);
int keylen_rem = keylen % sizeof(dword);
// Determine how many times the key must be repeated to be dword aligned.
/* Determine how many times the key must be repeated to be dword aligned. */
int keycycle = keylen_rem ? (sizeof(dword) / keylen_rem) : 1;
int keyscount = (keylen * keycycle) / sizeof(dword);
// Allocate a buffer to hold the key as an array of dwords.
/* Allocate a buffer to hold the key as an array of dwords. */
dword* keys = new dword[keyscount];
// Copy the key into the key array, whilst mutating it.
/* Copy the key into the key array, whilst mutating it. */
for (int i = 0; i < keyscount; i++)
{
dword val;
@ -145,19 +145,19 @@ bool zen::crypt_firmware(const char* key, byte* buffer, size_t len)
keys[i] = (val - 0x01010101) | 0x80808080;
}
// Determine the number of dwords in the buffer.
/* Determine the number of dwords in the buffer. */
int len_div = len / sizeof(dword);
// Decrypt all dwords of the buffer.
/* Decrypt all dwords of the buffer. */
for (int i = 0; i < len_div; i++)
{
((dword*)buffer)[i] ^= keys[i % keyscount];
}
// Determine the remaining number of bytes in the buffer.
/* Determine the remaining number of bytes in the buffer. */
int len_rem = len % sizeof(dword);
// Decrypt the remaining number of bytes in the buffer.
/* Decrypt the remaining number of bytes in the buffer. */
for (int i = len_div * sizeof(dword); i < len; i++)
{
buffer[i] ^= ((key[i % keylen] - 0x01) | 0x80);