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author | rsc <devnull@localhost> | 2004-03-21 14:04:56 +0000 |
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committer | rsc <devnull@localhost> | 2004-03-21 14:04:56 +0000 |
commit | 0fc65b37a1e7585ca2347bf61dcb8bc3a6b146a4 (patch) | |
tree | dd9189a823998f494082adb769451f12be056566 /src/libsec/port/rsadecrypt.c | |
parent | 768206abfcf505fb034a0151bf263bc0b1f2380c (diff) | |
download | plan9port-0fc65b37a1e7585ca2347bf61dcb8bc3a6b146a4.tar.gz plan9port-0fc65b37a1e7585ca2347bf61dcb8bc3a6b146a4.tar.bz2 plan9port-0fc65b37a1e7585ca2347bf61dcb8bc3a6b146a4.zip |
Add most of libsec.
Diffstat (limited to 'src/libsec/port/rsadecrypt.c')
-rw-r--r-- | src/libsec/port/rsadecrypt.c | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/src/libsec/port/rsadecrypt.c b/src/libsec/port/rsadecrypt.c new file mode 100644 index 00000000..1e937bec --- /dev/null +++ b/src/libsec/port/rsadecrypt.c @@ -0,0 +1,37 @@ +#include "os.h" +#include <mp.h> +#include <libsec.h> + +// decrypt rsa using garner's algorithm for the chinese remainder theorem +// seminumerical algorithms, knuth, pp 253-254 +// applied cryptography, menezes et al, pg 612 +mpint* +rsadecrypt(RSApriv *rsa, mpint *in, mpint *out) +{ + mpint *v1, *v2; + + if(out == nil) + out = mpnew(0); + + // convert in to modular representation + v1 = mpnew(0); + mpmod(in, rsa->p, v1); + v2 = mpnew(0); + mpmod(in, rsa->q, v2); + + // exponentiate the modular rep + mpexp(v1, rsa->kp, rsa->p, v1); + mpexp(v2, rsa->kq, rsa->q, v2); + + // out = v1 + p*((v2-v1)*c2 mod q) + mpsub(v2, v1, v2); + mpmul(v2, rsa->c2, v2); + mpmod(v2, rsa->q, v2); + mpmul(v2, rsa->p, out); + mpadd(v1, out, out); + + mpfree(v1); + mpfree(v2); + + return out; +} |