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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/dsasign.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/dsasign.c')
-rw-r--r-- | src/libsec/port/dsasign.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/src/libsec/port/dsasign.c b/src/libsec/port/dsasign.c new file mode 100644 index 00000000..137134be --- /dev/null +++ b/src/libsec/port/dsasign.c @@ -0,0 +1,52 @@ +#include "os.h" +#include <mp.h> +#include <libsec.h> + +DSAsig* +dsasign(DSApriv *priv, mpint *m) +{ + DSApub *pub = &priv->pub; + DSAsig *sig; + mpint *qm1, *k, *kinv, *r, *s; + mpint *q = pub->q, *p = pub->p, *alpha = pub->alpha; + int qlen = mpsignif(q); + + qm1 = mpnew(0); + kinv = mpnew(0); + r = mpnew(0); + s = mpnew(0); + k = mpnew(0); + mpsub(pub->q, mpone, qm1); + + // find a k that has an inverse mod q + while(1){ + mprand(qlen, genrandom, k); + if((mpcmp(mpone, k) > 0) || (mpcmp(k, pub->q) >= 0)) + continue; + mpextendedgcd(k, q, r, kinv, s); + if(mpcmp(r, mpone) != 0) + sysfatal("dsasign: pub->q not prime"); + break; + } + + // make kinv positive + mpmod(kinv, pub->q, kinv); + + // r = ((alpha**k) mod p) mod q + mpexp(alpha, k, p, r); + mpmod(r, q, r); + + // s = (kinv*(m + ar)) mod q + mpmul(r, priv->secret, s); + mpadd(s, m, s); + mpmul(s, kinv, s); + mpmod(s, q, s); + + sig = dsasigalloc(); + sig->r = r; + sig->s = s; + mpfree(qm1); + mpfree(k); + mpfree(kinv); + return sig; +} |