package im.actor.crypto.primitives.curve25519;
public class open {
//CONVERT #include <string.h>
//CONVERT #include "crypto_sign.h"
//CONVERT #include "crypto_hash_sha512.h"
//CONVERT #include "crypto_verify_32.h"
//CONVERT #include "ge.h"
//CONVERT #include "sc.h"
public static int crypto_sign_open(
Sha512 sha512provider,
byte[] m, long mlen,
byte[] sm, long smlen,
byte[] pk
)
{
byte[] pkcopy = new byte[32];
byte[] rcopy = new byte[32];
byte[] scopy = new byte[32];
byte[] h = new byte[64];
byte[] rcheck = new byte[32];
ge_p3 A = new ge_p3();
ge_p2 R = new ge_p2();
if (smlen < 64) return -1;
if ((sm[63] & 224) != 0) return -1;
if (ge_frombytes.ge_frombytes_negate_vartime(A,pk) != 0) return -1;
byte[] pubkeyhash = new byte[64];
sha512provider.calculateDigest(pubkeyhash,pk,32);
System.arraycopy(pk, 0, pkcopy, 0, 32);
System.arraycopy(sm, 0, rcopy, 0, 32);
System.arraycopy(sm, 32, scopy, 0, 32);
System.arraycopy(sm, 0, m, 0, (int)smlen);
System.arraycopy(pkcopy, 0, m, 32, 32);
sha512provider.calculateDigest(h,m,smlen);
sc_reduce.sc_reduce(h);
ge_double_scalarmult.ge_double_scalarmult_vartime(R,h,A,scopy);
ge_tobytes.ge_tobytes(rcheck,R);
if (crypto_verify_32.crypto_verify_32(rcheck,rcopy) == 0) {
System.arraycopy(m, 64, m, 0, (int)(smlen - 64));
//memset(m + smlen - 64,0,64);
return 0;
}
//badsig:
//memset(m,0,smlen);
return -1;
}
}