1 files changed, 78 insertions, 0 deletions
diff --git a/src/libsodium/crypto_sign/ed25519/ref10/open.c b/src/libsodium/crypto_sign/ed25519/ref10/open.c
new file mode 100644
index 0000000..36eb084
--- /dev/null
+++ b/src/libsodium/crypto_sign/ed25519/ref10/open.c
@@ -0,0 +1,78 @@
+
+#include <limits.h>
+#include <string.h>
+
+#include "api.h"
+#include "crypto_hash_sha512.h"
+#include "crypto_verify_32.h"
+#include "ge.h"
+#include "sc.h"
+#include "utils.h"
+
+int
+crypto_sign_verify_detached(const unsigned char *sig, const unsigned char *m,
+                            unsigned long long mlen, const unsigned char *pk)
+{
+    crypto_hash_sha512_state hs;
+    unsigned char h[64];
+    unsigned char rcheck[32];
+    unsigned int  i;
+    unsigned char d = 0;
+    ge_p3 A;
+    ge_p2 R;
+
+    if (sig[63] & 224) {
+        return -1;
+    }
+    if (ge_frombytes_negate_vartime(&A, pk) != 0) {
+        return -1;
+    }
+    for (i = 0; i < 32; ++i) {
+        d |= pk[i];
+    }
+    if (d == 0) {
+        return -1;
+    }
+    crypto_hash_sha512_init(&hs);
+    crypto_hash_sha512_update(&hs, sig, 32);
+    crypto_hash_sha512_update(&hs, pk, 32);
+    crypto_hash_sha512_update(&hs, m, mlen);
+    crypto_hash_sha512_final(&hs, h);
+    sc_reduce(h);
+
+    ge_double_scalarmult_vartime(&R, h, &A, sig + 32);
+    ge_tobytes(rcheck, &R);
+
+    if (crypto_verify_32(rcheck, sig) != 0) {
+        return -1;
+    }
+    if (sig == rcheck) {
+        return -1;
+    }
+    if (sodium_memcmp(sig, rcheck, 32) != 0) {
+        return -1;
+    }
+    return 0;
+}
+
+int
+crypto_sign_open(unsigned char *m, unsigned long long *mlen,
+                 const unsigned char *sm, unsigned long long smlen,
+                 const unsigned char *pk)
+{
+    if (smlen < 64 || smlen > SIZE_MAX) {
+        goto badsig;
+    }
+    if (crypto_sign_verify_detached(sm, sm + 64, smlen - 64, pk) != 0) {
+        memset(m, 0, smlen - 64);
+        goto badsig;
+    }
+    *mlen = smlen - 64;
+    memmove(m, sm + 64, *mlen);
+
+    return 0;
+
+badsig:
+    *mlen = 0;
+    return -1;
+}