Run util/openssl-format-source on the Curve448 code
[openssl.git] / crypto / ec / curve448 / eddsa.c
index 27f1fd5..0bf9b23 100644 (file)
 
 #if NO_CONTEXT
 const uint8_t NO_CONTEXT_POINTS_HERE = 0;
-const uint8_t * const DECAF_ED448_NO_CONTEXT = &NO_CONTEXT_POINTS_HERE;
+const uint8_t *const DECAF_ED448_NO_CONTEXT = &NO_CONTEXT_POINTS_HERE;
 #endif
 
-/* EDDSA_BASE_POINT_RATIO = 1 or 2
- * Because EdDSA25519 is not on E_d but on the isogenous E_sigma_d,
- * its base point is twice ours.
+/*
+ * EDDSA_BASE_POINT_RATIO = 1 or 2 Because EdDSA25519 is not on E_d but on the
+ * isogenous E_sigma_d, its base point is twice ours.
  */
 #define EDDSA_BASE_POINT_RATIO (1+EDDSA_USE_SIGMA_ISOGENY) /* TODO: remove */
 
@@ -45,8 +45,8 @@ static decaf_error_t oneshot_hash(uint8_t *out, size_t outlen,
         return DECAF_FAILURE;
 
     if (!EVP_DigestInit_ex(hashctx, EVP_shake256(), NULL)
-            || !EVP_DigestUpdate(hashctx, in, inlen)
-            || !EVP_DigestFinalXOF(hashctx, out, outlen)) {
+        || !EVP_DigestUpdate(hashctx, in, inlen)
+        || !EVP_DigestFinalXOF(hashctx, out, outlen)) {
         EVP_MD_CTX_free(hashctx);
         return DECAF_FAILURE;
     }
@@ -55,11 +55,10 @@ static decaf_error_t oneshot_hash(uint8_t *out, size_t outlen,
     return DECAF_SUCCESS;
 }
 
-
-static void clamp (
-    uint8_t secret_scalar_ser[DECAF_EDDSA_448_PRIVATE_BYTES]
-) {
-    uint8_t hibit = (1<<0)>>1;
+static void clamp(uint8_t secret_scalar_ser[DECAF_EDDSA_448_PRIVATE_BYTES]
+    )
+{
+    uint8_t hibit = (1 << 0) >> 1;
 
     /* Blarg */
     secret_scalar_ser[0] &= -COFACTOR;
@@ -67,18 +66,17 @@ static void clamp (
         secret_scalar_ser[DECAF_EDDSA_448_PRIVATE_BYTES - 1] = 0;
         secret_scalar_ser[DECAF_EDDSA_448_PRIVATE_BYTES - 2] |= 0x80;
     } else {
-        secret_scalar_ser[DECAF_EDDSA_448_PRIVATE_BYTES - 1] &= hibit-1;
+        secret_scalar_ser[DECAF_EDDSA_448_PRIVATE_BYTES - 1] &= hibit - 1;
         secret_scalar_ser[DECAF_EDDSA_448_PRIVATE_BYTES - 1] |= hibit;
     }
 }
 
-static decaf_error_t hash_init_with_dom(
-    EVP_MD_CTX *hashctx,
-    uint8_t prehashed,
-    uint8_t for_prehash,
-    const uint8_t *context,
-    size_t context_len
-) {
+static decaf_error_t hash_init_with_dom(EVP_MD_CTX *hashctx,
+                                        uint8_t prehashed,
+                                        uint8_t for_prehash,
+                                        const uint8_t *context,
+                                        size_t context_len)
+{
     const char *dom_s = "SigEd448";
     uint8_t dom[2];
 
@@ -99,33 +97,38 @@ static decaf_error_t hash_init_with_dom(
 #endif
 
     if (!EVP_DigestInit_ex(hashctx, EVP_shake256(), NULL)
-            || !EVP_DigestUpdate(hashctx, dom_s, strlen(dom_s))
-            || !EVP_DigestUpdate(hashctx, dom, sizeof(dom))
-            || !EVP_DigestUpdate(hashctx, context, context_len))
+        || !EVP_DigestUpdate(hashctx, dom_s, strlen(dom_s))
+        || !EVP_DigestUpdate(hashctx, dom, sizeof(dom))
+        || !EVP_DigestUpdate(hashctx, context, context_len))
         return DECAF_FAILURE;
 
     return DECAF_SUCCESS;
 }
 
 /* In this file because it uses the hash */
-decaf_error_t decaf_ed448_convert_private_key_to_x448 (
-    uint8_t x[DECAF_X448_PRIVATE_BYTES],
-    const uint8_t ed[DECAF_EDDSA_448_PRIVATE_BYTES]
-) {
+decaf_error_t decaf_ed448_convert_private_key_to_x448(uint8_t
+                                                      x
+                                                      [DECAF_X448_PRIVATE_BYTES],
+                                                      const uint8_t
+                                                      ed
+                                                      [DECAF_EDDSA_448_PRIVATE_BYTES]
+    )
+{
     /* pass the private key through oneshot_hash function */
     /* and keep the first DECAF_X448_PRIVATE_BYTES bytes */
-    return oneshot_hash(
-        x,
-        DECAF_X448_PRIVATE_BYTES,
-        ed,
-        DECAF_EDDSA_448_PRIVATE_BYTES
-    );
+    return oneshot_hash(x,
+                        DECAF_X448_PRIVATE_BYTES,
+                        ed, DECAF_EDDSA_448_PRIVATE_BYTES);
 }
-    
-decaf_error_t decaf_ed448_derive_public_key (
-    uint8_t pubkey[DECAF_EDDSA_448_PUBLIC_BYTES],
-    const uint8_t privkey[DECAF_EDDSA_448_PRIVATE_BYTES]
-) {
+
+decaf_error_t decaf_ed448_derive_public_key(uint8_t
+                                            pubkey
+                                            [DECAF_EDDSA_448_PUBLIC_BYTES],
+                                            const uint8_t
+                                            privkey
+                                            [DECAF_EDDSA_448_PRIVATE_BYTES]
+    )
+{
     /* only this much used for keygen */
     uint8_t secret_scalar_ser[DECAF_EDDSA_448_PRIVATE_BYTES];
     curve448_scalar_t secret_scalar;
@@ -138,22 +141,25 @@ decaf_error_t decaf_ed448_derive_public_key (
     }
     clamp(secret_scalar_ser);
 
-    curve448_scalar_decode_long(secret_scalar, secret_scalar_ser, sizeof(secret_scalar_ser));
-    
-    /* Since we are going to mul_by_cofactor during encoding, divide by it here.
-     * However, the EdDSA base point is not the same as the decaf base point if
-     * the sigma isogeny is in use: the EdDSA base point is on Etwist_d/(1-d) and
-     * the decaf base point is on Etwist_d, and when converted it effectively
-     * picks up a factor of 2 from the isogenies.  So we might start at 2 instead of 1. 
+    curve448_scalar_decode_long(secret_scalar, secret_scalar_ser,
+                                sizeof(secret_scalar_ser));
+
+    /*
+     * Since we are going to mul_by_cofactor during encoding, divide by it
+     * here. However, the EdDSA base point is not the same as the decaf base
+     * point if the sigma isogeny is in use: the EdDSA base point is on
+     * Etwist_d/(1-d) and the decaf base point is on Etwist_d, and when
+     * converted it effectively picks up a factor of 2 from the isogenies.  So
+     * we might start at 2 instead of 1.
      */
-    for (c=1; c<DECAF_448_EDDSA_ENCODE_RATIO; c <<= 1) {
-        curve448_scalar_halve(secret_scalar,secret_scalar);
+    for (c = 1; c < DECAF_448_EDDSA_ENCODE_RATIO; c <<= 1) {
+        curve448_scalar_halve(secret_scalar, secret_scalar);
     }
-    
-    curve448_precomputed_scalarmul(p,curve448_precomputed_base,secret_scalar);
-    
+
+    curve448_precomputed_scalarmul(p, curve448_precomputed_base, secret_scalar);
+
     curve448_point_mul_by_ratio_and_encode_like_eddsa(pubkey, p);
-        
+
     /* Cleanup */
     curve448_scalar_destroy(secret_scalar);
     curve448_point_destroy(p);
@@ -162,21 +168,21 @@ decaf_error_t decaf_ed448_derive_public_key (
     return DECAF_SUCCESS;
 }
 
-decaf_error_t decaf_ed448_sign (
-    uint8_t signature[DECAF_EDDSA_448_SIGNATURE_BYTES],
-    const uint8_t privkey[DECAF_EDDSA_448_PRIVATE_BYTES],
-    const uint8_t pubkey[DECAF_EDDSA_448_PUBLIC_BYTES],
-    const uint8_t *message,
-    size_t message_len,
-    uint8_t prehashed,
-    const uint8_t *context,
-    size_t context_len
-{
+decaf_error_t decaf_ed448_sign(uint8_t
+                               signature[DECAF_EDDSA_448_SIGNATURE_BYTES],
+                               const uint8_t
+                               privkey[DECAF_EDDSA_448_PRIVATE_BYTES],
+                               const uint8_t
+                               pubkey[DECAF_EDDSA_448_PUBLIC_BYTES],
+                               const uint8_t *message, size_t message_len,
+                               uint8_t prehashed, const uint8_t *context,
+                               size_t context_len)
+{
     curve448_scalar_t secret_scalar;
     EVP_MD_CTX *hashctx = EVP_MD_CTX_new();
     decaf_error_t ret = DECAF_FAILURE;
     curve448_scalar_t nonce_scalar;
-    uint8_t nonce_point[DECAF_EDDSA_448_PUBLIC_BYTES] = {0};
+    uint8_t nonce_point[DECAF_EDDSA_448_PUBLIC_BYTES] = { 0 };
     unsigned int c;
     curve448_scalar_t challenge_scalar;
 
@@ -188,28 +194,28 @@ decaf_error_t decaf_ed448_sign (
         struct {
             uint8_t secret_scalar_ser[DECAF_EDDSA_448_PRIVATE_BYTES];
             uint8_t seed[DECAF_EDDSA_448_PRIVATE_BYTES];
-        } __attribute__((packed)) expanded;
+        } __attribute__ ((packed)) expanded;
 
         if (!oneshot_hash((uint8_t *)&expanded, sizeof(expanded), privkey,
                           DECAF_EDDSA_448_PRIVATE_BYTES))
             goto err;
-        clamp(expanded.secret_scalar_ser);   
-        curve448_scalar_decode_long(secret_scalar, expanded.secret_scalar_ser, sizeof(expanded.secret_scalar_ser));
-    
+        clamp(expanded.secret_scalar_ser);
+        curve448_scalar_decode_long(secret_scalar, expanded.secret_scalar_ser,
+                                    sizeof(expanded.secret_scalar_ser));
+
         /* Hash to create the nonce */
         if (!hash_init_with_dom(hashctx, prehashed, 0, context, context_len)
-                || !EVP_DigestUpdate(hashctx, expanded.seed,
-                                     sizeof(expanded.seed))
-                || !EVP_DigestUpdate(hashctx, message, message_len)) {
+            || !EVP_DigestUpdate(hashctx, expanded.seed, sizeof(expanded.seed))
+            || !EVP_DigestUpdate(hashctx, message, message_len)) {
             OPENSSL_cleanse(&expanded, sizeof(expanded));
             goto err;
         }
         OPENSSL_cleanse(&expanded, sizeof(expanded));
     }
-    
+
     /* Decode the nonce */
     {
-        uint8_t nonce[2*DECAF_EDDSA_448_PRIVATE_BYTES];
+        uint8_t nonce[2 * DECAF_EDDSA_448_PRIVATE_BYTES];
 
         if (!EVP_DigestFinalXOF(hashctx, nonce, sizeof(nonce)))
             goto err;
@@ -222,40 +228,42 @@ decaf_error_t decaf_ed448_sign (
         curve448_scalar_t nonce_scalar_2;
         curve448_point_t p;
 
-        curve448_scalar_halve(nonce_scalar_2,nonce_scalar);
+        curve448_scalar_halve(nonce_scalar_2, nonce_scalar);
         for (c = 2; c < DECAF_448_EDDSA_ENCODE_RATIO; c <<= 1) {
-            curve448_scalar_halve(nonce_scalar_2,nonce_scalar_2);
+            curve448_scalar_halve(nonce_scalar_2, nonce_scalar_2);
         }
 
-        curve448_precomputed_scalarmul(p,curve448_precomputed_base,nonce_scalar_2);
+        curve448_precomputed_scalarmul(p, curve448_precomputed_base,
+                                       nonce_scalar_2);
         curve448_point_mul_by_ratio_and_encode_like_eddsa(nonce_point, p);
         curve448_point_destroy(p);
         curve448_scalar_destroy(nonce_scalar_2);
     }
 
     {
-        uint8_t challenge[2*DECAF_EDDSA_448_PRIVATE_BYTES];
+        uint8_t challenge[2 * DECAF_EDDSA_448_PRIVATE_BYTES];
 
         /* Compute the challenge */
         if (!hash_init_with_dom(hashctx, prehashed, 0, context, context_len)
-                || !EVP_DigestUpdate(hashctx, nonce_point, sizeof(nonce_point))
-                || !EVP_DigestUpdate(hashctx, pubkey,
-                                     DECAF_EDDSA_448_PUBLIC_BYTES)
-                || !EVP_DigestUpdate(hashctx, message, message_len)
-                || !EVP_DigestFinalXOF(hashctx, challenge, sizeof(challenge)))
+            || !EVP_DigestUpdate(hashctx, nonce_point, sizeof(nonce_point))
+            || !EVP_DigestUpdate(hashctx, pubkey, DECAF_EDDSA_448_PUBLIC_BYTES)
+            || !EVP_DigestUpdate(hashctx, message, message_len)
+            || !EVP_DigestFinalXOF(hashctx, challenge, sizeof(challenge)))
             goto err;
 
-        curve448_scalar_decode_long(challenge_scalar,challenge,sizeof(challenge));
-        OPENSSL_cleanse(challenge,sizeof(challenge));
+        curve448_scalar_decode_long(challenge_scalar, challenge,
+                                    sizeof(challenge));
+        OPENSSL_cleanse(challenge, sizeof(challenge));
     }
-    
-    curve448_scalar_mul(challenge_scalar,challenge_scalar,secret_scalar);
-    curve448_scalar_add(challenge_scalar,challenge_scalar,nonce_scalar);
-    
-    OPENSSL_cleanse(signature,DECAF_EDDSA_448_SIGNATURE_BYTES);
-    memcpy(signature,nonce_point,sizeof(nonce_point));
-    curve448_scalar_encode(&signature[DECAF_EDDSA_448_PUBLIC_BYTES],challenge_scalar);
-    
+
+    curve448_scalar_mul(challenge_scalar, challenge_scalar, secret_scalar);
+    curve448_scalar_add(challenge_scalar, challenge_scalar, nonce_scalar);
+
+    OPENSSL_cleanse(signature, DECAF_EDDSA_448_SIGNATURE_BYTES);
+    memcpy(signature, nonce_point, sizeof(nonce_point));
+    curve448_scalar_encode(&signature[DECAF_EDDSA_448_PUBLIC_BYTES],
+                           challenge_scalar);
+
     curve448_scalar_destroy(secret_scalar);
     curve448_scalar_destroy(nonce_scalar);
     curve448_scalar_destroy(challenge_scalar);
@@ -266,97 +274,103 @@ decaf_error_t decaf_ed448_sign (
     return ret;
 }
 
-
-decaf_error_t decaf_ed448_sign_prehash (
-    uint8_t signature[DECAF_EDDSA_448_SIGNATURE_BYTES],
-    const uint8_t privkey[DECAF_EDDSA_448_PRIVATE_BYTES],
-    const uint8_t pubkey[DECAF_EDDSA_448_PUBLIC_BYTES],
-    const uint8_t hash[64],
-    const uint8_t *context,
-    size_t context_len
-) {
-    return decaf_ed448_sign(signature,privkey,pubkey,hash,64,1,context,
+decaf_error_t decaf_ed448_sign_prehash(uint8_t
+                                       signature
+                                       [DECAF_EDDSA_448_SIGNATURE_BYTES],
+                                       const uint8_t
+                                       privkey[DECAF_EDDSA_448_PRIVATE_BYTES],
+                                       const uint8_t
+                                       pubkey[DECAF_EDDSA_448_PUBLIC_BYTES],
+                                       const uint8_t hash[64],
+                                       const uint8_t *context,
+                                       size_t context_len)
+{
+    return decaf_ed448_sign(signature, privkey, pubkey, hash, 64, 1, context,
                             context_len);
-    /*OPENSSL_cleanse(hash,sizeof(hash));*/
+    /*
+     * OPENSSL_cleanse(hash,sizeof(hash));
+     */
 }
 
-decaf_error_t decaf_ed448_verify (
-    const uint8_t signature[DECAF_EDDSA_448_SIGNATURE_BYTES],
-    const uint8_t pubkey[DECAF_EDDSA_448_PUBLIC_BYTES],
-    const uint8_t *message,
-    size_t message_len,
-    uint8_t prehashed,
-    const uint8_t *context,
-    uint8_t context_len
-) { 
+decaf_error_t decaf_ed448_verify(const uint8_t
+                                 signature[DECAF_EDDSA_448_SIGNATURE_BYTES],
+                                 const uint8_t
+                                 pubkey[DECAF_EDDSA_448_PUBLIC_BYTES],
+                                 const uint8_t *message, size_t message_len,
+                                 uint8_t prehashed, const uint8_t *context,
+                                 uint8_t context_len)
+{
     curve448_point_t pk_point, r_point;
-    decaf_error_t error = curve448_point_decode_like_eddsa_and_mul_by_ratio(pk_point,pubkey);
+    decaf_error_t error =
+        curve448_point_decode_like_eddsa_and_mul_by_ratio(pk_point, pubkey);
     curve448_scalar_t challenge_scalar;
     curve448_scalar_t response_scalar;
     unsigned int c;
 
-    if (DECAF_SUCCESS != error) { return error; }
-    
-    error = curve448_point_decode_like_eddsa_and_mul_by_ratio(r_point,signature);
-    if (DECAF_SUCCESS != error) { return error; }
-    
+    if (DECAF_SUCCESS != error) {
+        return error;
+    }
+
+    error =
+        curve448_point_decode_like_eddsa_and_mul_by_ratio(r_point, signature);
+    if (DECAF_SUCCESS != error) {
+        return error;
+    }
+
     {
         /* Compute the challenge */
         EVP_MD_CTX *hashctx = EVP_MD_CTX_new();
-        uint8_t challenge[2*DECAF_EDDSA_448_PRIVATE_BYTES];
+        uint8_t challenge[2 * DECAF_EDDSA_448_PRIVATE_BYTES];
 
         if (hashctx == NULL
-                || !hash_init_with_dom(hashctx, prehashed, 0, context,
-                                       context_len)
-                || !EVP_DigestUpdate(hashctx, signature,
-                                     DECAF_EDDSA_448_PUBLIC_BYTES)
-                || !EVP_DigestUpdate(hashctx, pubkey,
-                                     DECAF_EDDSA_448_PUBLIC_BYTES)
-                || !EVP_DigestUpdate(hashctx, message, message_len)
-                || !EVP_DigestFinalXOF(hashctx, challenge, sizeof(challenge))) {
+            || !hash_init_with_dom(hashctx, prehashed, 0, context, context_len)
+            || !EVP_DigestUpdate(hashctx, signature,
+                                 DECAF_EDDSA_448_PUBLIC_BYTES)
+            || !EVP_DigestUpdate(hashctx, pubkey, DECAF_EDDSA_448_PUBLIC_BYTES)
+            || !EVP_DigestUpdate(hashctx, message, message_len)
+            || !EVP_DigestFinalXOF(hashctx, challenge, sizeof(challenge))) {
             EVP_MD_CTX_free(hashctx);
             return DECAF_FAILURE;
         }
 
         EVP_MD_CTX_free(hashctx);
-        curve448_scalar_decode_long(challenge_scalar,challenge,sizeof(challenge));
-        OPENSSL_cleanse(challenge,sizeof(challenge));
+        curve448_scalar_decode_long(challenge_scalar, challenge,
+                                    sizeof(challenge));
+        OPENSSL_cleanse(challenge, sizeof(challenge));
     }
-    curve448_scalar_sub(challenge_scalar, curve448_scalar_zero, challenge_scalar);
-
-    curve448_scalar_decode_long(
-        response_scalar,
-        &signature[DECAF_EDDSA_448_PUBLIC_BYTES],
-        DECAF_EDDSA_448_PRIVATE_BYTES
-    );
-    
-    for (c=1; c<DECAF_448_EDDSA_DECODE_RATIO; c<<=1) {
-        curve448_scalar_add(response_scalar,response_scalar,response_scalar);
+    curve448_scalar_sub(challenge_scalar, curve448_scalar_zero,
+                        challenge_scalar);
+
+    curve448_scalar_decode_long(response_scalar,
+                                &signature[DECAF_EDDSA_448_PUBLIC_BYTES],
+                                DECAF_EDDSA_448_PRIVATE_BYTES);
+
+    for (c = 1; c < DECAF_448_EDDSA_DECODE_RATIO; c <<= 1) {
+        curve448_scalar_add(response_scalar, response_scalar, response_scalar);
     }
-    
-    
+
     /* pk_point = -c(x(P)) + (cx + k)G = kG */
-    curve448_base_double_scalarmul_non_secret(
-        pk_point,
-        response_scalar,
-        pk_point,
-        challenge_scalar
-    );
-    return decaf_succeed_if(curve448_point_eq(pk_point,r_point));
+    curve448_base_double_scalarmul_non_secret(pk_point,
+                                              response_scalar,
+                                              pk_point, challenge_scalar);
+    return decaf_succeed_if(curve448_point_eq(pk_point, r_point));
 }
 
-
-decaf_error_t decaf_ed448_verify_prehash (
-    const uint8_t signature[DECAF_EDDSA_448_SIGNATURE_BYTES],
-    const uint8_t pubkey[DECAF_EDDSA_448_PUBLIC_BYTES],
-    const uint8_t hash[64],
-    const uint8_t *context,
-    uint8_t context_len
-) {
+decaf_error_t decaf_ed448_verify_prehash(const uint8_t
+                                         signature
+                                         [DECAF_EDDSA_448_SIGNATURE_BYTES],
+                                         const uint8_t
+                                         pubkey[DECAF_EDDSA_448_PUBLIC_BYTES],
+                                         const uint8_t hash[64],
+                                         const uint8_t *context,
+                                         uint8_t context_len)
+{
     decaf_error_t ret;
-    
-    ret = decaf_ed448_verify(signature,pubkey,hash,64,1,context,context_len);
-    
+
+    ret =
+        decaf_ed448_verify(signature, pubkey, hash, 64, 1, context,
+                           context_len);
+
     return ret;
 }
 
@@ -367,10 +381,9 @@ int ED448_sign(uint8_t *out_sig, const uint8_t *message, size_t message_len,
 
     return decaf_ed448_sign(out_sig, private_key, public_key, message,
                             message_len, 0, context, context_len)
-                            == DECAF_SUCCESS;
+        == DECAF_SUCCESS;
 }
 
-
 int ED448_verify(const uint8_t *message, size_t message_len,
                  const uint8_t signature[114], const uint8_t public_key[57],
                  const uint8_t *context, size_t context_len)
@@ -397,8 +410,8 @@ int ED448ph_verify(const uint8_t hash[64], const uint8_t signature[114],
 }
 
 int ED448_public_from_private(uint8_t out_public_key[57],
-                               const uint8_t private_key[57])
+                              const uint8_t private_key[57])
 {
     return decaf_ed448_derive_public_key(out_public_key, private_key)
-           == DECAF_SUCCESS;
+        == DECAF_SUCCESS;
 }