1 files changed, 93 insertions, 0 deletions
diff --git a/libs/libsodium/src/crypto_sign/ed25519/ref10/open.c b/libs/libsodium/src/crypto_sign/ed25519/ref10/open.c
new file mode 100644
index 0000000000..c9e8843c1e
--- /dev/null
+++ b/libs/libsodium/src/crypto_sign/ed25519/ref10/open.c
@@ -0,0 +1,93 @@
+
+#include <limits.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "crypto_hash_sha512.h"
+#include "crypto_sign_ed25519.h"
+#include "crypto_verify_32.h"
+#include "sign_ed25519_ref10.h"
+#include "private/ed25519_ref10.h"
+#include "utils.h"
+
+int
+_crypto_sign_ed25519_verify_detached(const unsigned char *sig,
+                                     const unsigned char *m,
+                                     unsigned long long   mlen,
+                                     const unsigned char *pk,
+                                     int prehashed)
+{
+    crypto_hash_sha512_state hs;
+    unsigned char            h[64];
+    unsigned char            rcheck[32];
+    ge25519_p3               A;
+    ge25519_p2               R;
+
+#ifndef ED25519_COMPAT
+    if (sc25519_is_canonical(sig + 32) == 0 ||
+        ge25519_has_small_order(sig) != 0) {
+        return -1;
+    }
+    if (ge25519_is_canonical(pk) == 0) {
+        return -1;
+    }
+#else
+    if (sig[63] & 224) {
+        return -1;
+    }
+#endif
+    if (ge25519_has_small_order(pk) != 0 ||
+        ge25519_frombytes_negate_vartime(&A, pk) != 0) {
+        return -1;
+    }
+    _crypto_sign_ed25519_ref10_hinit(&hs, prehashed);
+    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);
+    sc25519_reduce(h);
+
+    ge25519_double_scalarmult_vartime(&R, h, &A, sig + 32);
+    ge25519_tobytes(rcheck, &R);
+
+    return crypto_verify_32(rcheck, sig) | (-(rcheck == sig)) |
+           sodium_memcmp(sig, rcheck, 32);
+}
+
+int
+crypto_sign_ed25519_verify_detached(const unsigned char *sig,
+                                    const unsigned char *m,
+                                    unsigned long long   mlen,
+                                    const unsigned char *pk)
+{
+    return _crypto_sign_ed25519_verify_detached(sig, m, mlen, pk, 0);
+}
+
+int
+crypto_sign_ed25519_open(unsigned char *m, unsigned long long *mlen_p,
+                         const unsigned char *sm, unsigned long long smlen,
+                         const unsigned char *pk)
+{
+    unsigned long long mlen;
+
+    if (smlen < 64 || smlen - 64 > crypto_sign_ed25519_MESSAGEBYTES_MAX) {
+        goto badsig;
+    }
+    mlen = smlen - 64;
+    if (crypto_sign_ed25519_verify_detached(sm, sm + 64, mlen, pk) != 0) {
+        memset(m, 0, mlen);
+        goto badsig;
+    }
+    if (mlen_p != NULL) {
+        *mlen_p = mlen;
+    }
+    memmove(m, sm + 64, mlen);
+
+    return 0;
+
+badsig:
+    if (mlen_p != NULL) {
+        *mlen_p = 0;
+    }
+    return -1;
+}