Run util/openssl-format-source -v -c .
[openssl.git] / crypto / ec / ecp_oct.c
index 0fdd8ad31fc73f3cd844c442bb13a74d9b35fbd2..77627bb5c47f4d393ef0c52a13c515ac39dea40a 100644 (file)
@@ -1,8 +1,9 @@
 /* crypto/ec/ecp_oct.c */
-/* Includes code written by Lenka Fibikova <fibikova@exp-math.uni-essen.de>
- * for the OpenSSL project. 
- * Includes code written by Bodo Moeller for the OpenSSL project.
-*/
+/*
+ * Includes code written by Lenka Fibikova <fibikova@exp-math.uni-essen.de>
+ * for the OpenSSL project. Includes code written by Bodo Moeller for the
+ * OpenSSL project.
+ */
 /* ====================================================================
  * Copyright (c) 1998-2002 The OpenSSL Project.  All rights reserved.
  *
@@ -11,7 +12,7 @@
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer. 
+ *    notice, this list of conditions and the following disclaimer.
  *
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in
 
 #include "ec_lcl.h"
 
-int ec_GFp_simple_set_compressed_coordinates(const EC_GROUP *group, EC_POINT *point,
-       const BIGNUM *x_, int y_bit, BN_CTX *ctx)
-       {
-       BN_CTX *new_ctx = NULL;
-       BIGNUM *tmp1, *tmp2, *x, *y;
-       int ret = 0;
-
-       /* clear error queue*/
-       ERR_clear_error();
-
-       if (ctx == NULL)
-               {
-               ctx = new_ctx = BN_CTX_new();
-               if (ctx == NULL)
-                       return 0;
-               }
-
-       y_bit = (y_bit != 0);
-
-       BN_CTX_start(ctx);
-       tmp1 = BN_CTX_get(ctx);
-       tmp2 = BN_CTX_get(ctx);
-       x = BN_CTX_get(ctx);
-       y = BN_CTX_get(ctx);
-       if (y == NULL) goto err;
-
-       /*-
-        * Recover y.  We have a Weierstrass equation
-        *     y^2 = x^3 + a*x + b,
-        * so  y  is one of the square roots of  x^3 + a*x + b.
-        */
-
-       /* tmp1 := x^3 */
-       if (!BN_nnmod(x, x_, &group->field,ctx)) goto err;
-       if (group->meth->field_decode == 0)
-               {
-               /* field_{sqr,mul} work on standard representation */
-               if (!group->meth->field_sqr(group, tmp2, x_, ctx)) goto err;
-               if (!group->meth->field_mul(group, tmp1, tmp2, x_, ctx)) goto err;
-               }
-       else
-               {
-               if (!BN_mod_sqr(tmp2, x_, &group->field, ctx)) goto err;
-               if (!BN_mod_mul(tmp1, tmp2, x_, &group->field, ctx)) goto err;
-               }
-       
-       /* tmp1 := tmp1 + a*x */
-       if (group->a_is_minus3)
-               {
-               if (!BN_mod_lshift1_quick(tmp2, x, &group->field)) goto err;
-               if (!BN_mod_add_quick(tmp2, tmp2, x, &group->field)) goto err;
-               if (!BN_mod_sub_quick(tmp1, tmp1, tmp2, &group->field)) goto err;
-               }
-       else
-               {
-               if (group->meth->field_decode)
-                       {
-                       if (!group->meth->field_decode(group, tmp2, &group->a, ctx)) goto err;
-                       if (!BN_mod_mul(tmp2, tmp2, x, &group->field, ctx)) goto err;
-                       }
-               else
-                       {
-                       /* field_mul works on standard representation */
-                       if (!group->meth->field_mul(group, tmp2, &group->a, x, ctx)) goto err;
-                       }
-               
-               if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field)) goto err;
-               }
-       
-       /* tmp1 := tmp1 + b */
-       if (group->meth->field_decode)
-               {
-               if (!group->meth->field_decode(group, tmp2, &group->b, ctx)) goto err;
-               if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field)) goto err;
-               }
-       else
-               {
-               if (!BN_mod_add_quick(tmp1, tmp1, &group->b, &group->field)) goto err;
-               }
-       
-       if (!BN_mod_sqrt(y, tmp1, &group->field, ctx))
-               {
-               unsigned long err = ERR_peek_last_error();
-               
-               if (ERR_GET_LIB(err) == ERR_LIB_BN && ERR_GET_REASON(err) == BN_R_NOT_A_SQUARE)
-                       {
-                       ERR_clear_error();
-                       ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSED_POINT);
-                       }
-               else
-                       ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, ERR_R_BN_LIB);
-               goto err;
-               }
-
-       if (y_bit != BN_is_odd(y))
-               {
-               if (BN_is_zero(y))
-                       {
-                       int kron;
-
-                       kron = BN_kronecker(x, &group->field, ctx);
-                       if (kron == -2) goto err;
-
-                       if (kron == 1)
-                               ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSION_BIT);
-                       else
-                               /* BN_mod_sqrt() should have cought this error (not a square) */
-                               ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSED_POINT);
-                       goto err;
-                       }
-               if (!BN_usub(y, &group->field, y)) goto err;
-               }
-       if (y_bit != BN_is_odd(y))
-               {
-               ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, ERR_R_INTERNAL_ERROR);
-               goto err;
-               }
-
-       if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) goto err;
-
-       ret = 1;
+int ec_GFp_simple_set_compressed_coordinates(const EC_GROUP *group,
+                                             EC_POINT *point,
+                                             const BIGNUM *x_, int y_bit,
+                                             BN_CTX *ctx)
+{
+    BN_CTX *new_ctx = NULL;
+    BIGNUM *tmp1, *tmp2, *x, *y;
+    int ret = 0;
+
+    /* clear error queue */
+    ERR_clear_error();
+
+    if (ctx == NULL) {
+        ctx = new_ctx = BN_CTX_new();
+        if (ctx == NULL)
+            return 0;
+    }
+
+    y_bit = (y_bit != 0);
+
+    BN_CTX_start(ctx);
+    tmp1 = BN_CTX_get(ctx);
+    tmp2 = BN_CTX_get(ctx);
+    x = BN_CTX_get(ctx);
+    y = BN_CTX_get(ctx);
+    if (y == NULL)
+        goto err;
+
+        /*-
+         * Recover y.  We have a Weierstrass equation
+         *     y^2 = x^3 + a*x + b,
+         * so  y  is one of the square roots of  x^3 + a*x + b.
+         */
+
+    /* tmp1 := x^3 */
+    if (!BN_nnmod(x, x_, &group->field, ctx))
+        goto err;
+    if (group->meth->field_decode == 0) {
+        /* field_{sqr,mul} work on standard representation */
+        if (!group->meth->field_sqr(group, tmp2, x_, ctx))
+            goto err;
+        if (!group->meth->field_mul(group, tmp1, tmp2, x_, ctx))
+            goto err;
+    } else {
+        if (!BN_mod_sqr(tmp2, x_, &group->field, ctx))
+            goto err;
+        if (!BN_mod_mul(tmp1, tmp2, x_, &group->field, ctx))
+            goto err;
+    }
+
+    /* tmp1 := tmp1 + a*x */
+    if (group->a_is_minus3) {
+        if (!BN_mod_lshift1_quick(tmp2, x, &group->field))
+            goto err;
+        if (!BN_mod_add_quick(tmp2, tmp2, x, &group->field))
+            goto err;
+        if (!BN_mod_sub_quick(tmp1, tmp1, tmp2, &group->field))
+            goto err;
+    } else {
+        if (group->meth->field_decode) {
+            if (!group->meth->field_decode(group, tmp2, &group->a, ctx))
+                goto err;
+            if (!BN_mod_mul(tmp2, tmp2, x, &group->field, ctx))
+                goto err;
+        } else {
+            /* field_mul works on standard representation */
+            if (!group->meth->field_mul(group, tmp2, &group->a, x, ctx))
+                goto err;
+        }
+
+        if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field))
+            goto err;
+    }
+
+    /* tmp1 := tmp1 + b */
+    if (group->meth->field_decode) {
+        if (!group->meth->field_decode(group, tmp2, &group->b, ctx))
+            goto err;
+        if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field))
+            goto err;
+    } else {
+        if (!BN_mod_add_quick(tmp1, tmp1, &group->b, &group->field))
+            goto err;
+    }
+
+    if (!BN_mod_sqrt(y, tmp1, &group->field, ctx)) {
+        unsigned long err = ERR_peek_last_error();
+
+        if (ERR_GET_LIB(err) == ERR_LIB_BN
+            && ERR_GET_REASON(err) == BN_R_NOT_A_SQUARE) {
+            ERR_clear_error();
+            ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
+                  EC_R_INVALID_COMPRESSED_POINT);
+        } else
+            ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
+                  ERR_R_BN_LIB);
+        goto err;
+    }
+
+    if (y_bit != BN_is_odd(y)) {
+        if (BN_is_zero(y)) {
+            int kron;
+
+            kron = BN_kronecker(x, &group->field, ctx);
+            if (kron == -2)
+                goto err;
+
+            if (kron == 1)
+                ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
+                      EC_R_INVALID_COMPRESSION_BIT);
+            else
+                /*
+                 * BN_mod_sqrt() should have cought this error (not a square)
+                 */
+                ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
+                      EC_R_INVALID_COMPRESSED_POINT);
+            goto err;
+        }
+        if (!BN_usub(y, &group->field, y))
+            goto err;
+    }
+    if (y_bit != BN_is_odd(y)) {
+        ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
+              ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+
+    if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx))
+        goto err;
+
+    ret = 1;
 
  err:
-       BN_CTX_end(ctx);
-       if (new_ctx != NULL)
-               BN_CTX_free(new_ctx);
-       return ret;
-       }
-
-
-size_t ec_GFp_simple_point2oct(const EC_GROUP *group, const EC_POINT *point, point_conversion_form_t form,
-       unsigned char *buf, size_t len, BN_CTX *ctx)
-       {
-       size_t ret;
-       BN_CTX *new_ctx = NULL;
-       int used_ctx = 0;
-       BIGNUM *x, *y;
-       size_t field_len, i, skip;
-
-       if ((form != POINT_CONVERSION_COMPRESSED)
-               && (form != POINT_CONVERSION_UNCOMPRESSED)
-               && (form != POINT_CONVERSION_HYBRID))
-               {
-               ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_INVALID_FORM);
-               goto err;
-               }
-
-       if (EC_POINT_is_at_infinity(group, point))
-               {
-               /* encodes to a single 0 octet */
-               if (buf != NULL)
-                       {
-                       if (len < 1)
-                               {
-                               ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
-                               return 0;
-                               }
-                       buf[0] = 0;
-                       }
-               return 1;
-               }
-
-
-       /* ret := required output buffer length */
-       field_len = BN_num_bytes(&group->field);
-       ret = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2*field_len;
-
-       /* if 'buf' is NULL, just return required length */
-       if (buf != NULL)
-               {
-               if (len < ret)
-                       {
-                       ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
-                       goto err;
-                       }
-
-               if (ctx == NULL)
-                       {
-                       ctx = new_ctx = BN_CTX_new();
-                       if (ctx == NULL)
-                               return 0;
-                       }
-
-               BN_CTX_start(ctx);
-               used_ctx = 1;
-               x = BN_CTX_get(ctx);
-               y = BN_CTX_get(ctx);
-               if (y == NULL) goto err;
-
-               if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx)) goto err;
-
-               if ((form == POINT_CONVERSION_COMPRESSED || form == POINT_CONVERSION_HYBRID) && BN_is_odd(y))
-                       buf[0] = form + 1;
-               else
-                       buf[0] = form;
-       
-               i = 1;
-               
-               skip = field_len - BN_num_bytes(x);
-               if (skip > field_len)
-                       {
-                       ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
-                       goto err;
-                       }
-               while (skip > 0)
-                       {
-                       buf[i++] = 0;
-                       skip--;
-                       }
-               skip = BN_bn2bin(x, buf + i);
-               i += skip;
-               if (i != 1 + field_len)
-                       {
-                       ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
-                       goto err;
-                       }
-
-               if (form == POINT_CONVERSION_UNCOMPRESSED || form == POINT_CONVERSION_HYBRID)
-                       {
-                       skip = field_len - BN_num_bytes(y);
-                       if (skip > field_len)
-                               {
-                               ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
-                               goto err;
-                               }
-                       while (skip > 0)
-                               {
-                               buf[i++] = 0;
-                               skip--;
-                               }
-                       skip = BN_bn2bin(y, buf + i);
-                       i += skip;
-                       }
-
-               if (i != ret)
-                       {
-                       ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
-                       goto err;
-                       }
-               }
-       
-       if (used_ctx)
-               BN_CTX_end(ctx);
-       if (new_ctx != NULL)
-               BN_CTX_free(new_ctx);
-       return ret;
+    BN_CTX_end(ctx);
+    if (new_ctx != NULL)
+        BN_CTX_free(new_ctx);
+    return ret;
+}
+
+size_t ec_GFp_simple_point2oct(const EC_GROUP *group, const EC_POINT *point,
+                               point_conversion_form_t form,
+                               unsigned char *buf, size_t len, BN_CTX *ctx)
+{
+    size_t ret;
+    BN_CTX *new_ctx = NULL;
+    int used_ctx = 0;
+    BIGNUM *x, *y;
+    size_t field_len, i, skip;
+
+    if ((form != POINT_CONVERSION_COMPRESSED)
+        && (form != POINT_CONVERSION_UNCOMPRESSED)
+        && (form != POINT_CONVERSION_HYBRID)) {
+        ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_INVALID_FORM);
+        goto err;
+    }
+
+    if (EC_POINT_is_at_infinity(group, point)) {
+        /* encodes to a single 0 octet */
+        if (buf != NULL) {
+            if (len < 1) {
+                ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
+                return 0;
+            }
+            buf[0] = 0;
+        }
+        return 1;
+    }
+
+    /* ret := required output buffer length */
+    field_len = BN_num_bytes(&group->field);
+    ret =
+        (form ==
+         POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;
+
+    /* if 'buf' is NULL, just return required length */
+    if (buf != NULL) {
+        if (len < ret) {
+            ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
+            goto err;
+        }
+
+        if (ctx == NULL) {
+            ctx = new_ctx = BN_CTX_new();
+            if (ctx == NULL)
+                return 0;
+        }
+
+        BN_CTX_start(ctx);
+        used_ctx = 1;
+        x = BN_CTX_get(ctx);
+        y = BN_CTX_get(ctx);
+        if (y == NULL)
+            goto err;
+
+        if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx))
+            goto err;
+
+        if ((form == POINT_CONVERSION_COMPRESSED
+             || form == POINT_CONVERSION_HYBRID) && BN_is_odd(y))
+            buf[0] = form + 1;
+        else
+            buf[0] = form;
+
+        i = 1;
+
+        skip = field_len - BN_num_bytes(x);
+        if (skip > field_len) {
+            ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
+            goto err;
+        }
+        while (skip > 0) {
+            buf[i++] = 0;
+            skip--;
+        }
+        skip = BN_bn2bin(x, buf + i);
+        i += skip;
+        if (i != 1 + field_len) {
+            ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
+            goto err;
+        }
+
+        if (form == POINT_CONVERSION_UNCOMPRESSED
+            || form == POINT_CONVERSION_HYBRID) {
+            skip = field_len - BN_num_bytes(y);
+            if (skip > field_len) {
+                ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
+                goto err;
+            }
+            while (skip > 0) {
+                buf[i++] = 0;
+                skip--;
+            }
+            skip = BN_bn2bin(y, buf + i);
+            i += skip;
+        }
+
+        if (i != ret) {
+            ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
+            goto err;
+        }
+    }
+
+    if (used_ctx)
+        BN_CTX_end(ctx);
+    if (new_ctx != NULL)
+        BN_CTX_free(new_ctx);
+    return ret;
 
  err:
-       if (used_ctx)
-               BN_CTX_end(ctx);
-       if (new_ctx != NULL)
-               BN_CTX_free(new_ctx);
-       return 0;
-       }
-
+    if (used_ctx)
+        BN_CTX_end(ctx);
+    if (new_ctx != NULL)
+        BN_CTX_free(new_ctx);
+    return 0;
+}
 
 int ec_GFp_simple_oct2point(const EC_GROUP *group, EC_POINT *point,
-       const unsigned char *buf, size_t len, BN_CTX *ctx)
-       {
-       point_conversion_form_t form;
-       int y_bit;
-       BN_CTX *new_ctx = NULL;
-       BIGNUM *x, *y;
-       size_t field_len, enc_len;
-       int ret = 0;
-
-       if (len == 0)
-               {
-               ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_BUFFER_TOO_SMALL);
-               return 0;
-               }
-       form = buf[0];
-       y_bit = form & 1;
-       form = form & ~1U;
-       if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED)
-               && (form != POINT_CONVERSION_UNCOMPRESSED)
-               && (form != POINT_CONVERSION_HYBRID))
-               {
-               ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
-               return 0;
-               }
-       if ((form == 0 || form == POINT_CONVERSION_UNCOMPRESSED) && y_bit)
-               {
-               ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
-               return 0;
-               }
-
-       if (form == 0)
-               {
-               if (len != 1)
-                       {
-                       ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
-                       return 0;
-                       }
-
-               return EC_POINT_set_to_infinity(group, point);
-               }
-       
-       field_len = BN_num_bytes(&group->field);
-       enc_len = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2*field_len;
-
-       if (len != enc_len)
-               {
-               ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
-               return 0;
-               }
-
-       if (ctx == NULL)
-               {
-               ctx = new_ctx = BN_CTX_new();
-               if (ctx == NULL)
-                       return 0;
-               }
-
-       BN_CTX_start(ctx);
-       x = BN_CTX_get(ctx);
-       y = BN_CTX_get(ctx);
-       if (y == NULL) goto err;
-
-       if (!BN_bin2bn(buf + 1, field_len, x)) goto err;
-       if (BN_ucmp(x, &group->field) >= 0)
-               {
-               ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
-               goto err;
-               }
-
-       if (form == POINT_CONVERSION_COMPRESSED)
-               {
-               if (!EC_POINT_set_compressed_coordinates_GFp(group, point, x, y_bit, ctx)) goto err;
-               }
-       else
-               {
-               if (!BN_bin2bn(buf + 1 + field_len, field_len, y)) goto err;
-               if (BN_ucmp(y, &group->field) >= 0)
-                       {
-                       ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
-                       goto err;
-                       }
-               if (form == POINT_CONVERSION_HYBRID)
-                       {
-                       if (y_bit != BN_is_odd(y))
-                               {
-                               ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
-                               goto err;
-                               }
-                       }
-
-               if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) goto err;
-               }
-
-       /* test required by X9.62 */
-       if (!EC_POINT_is_on_curve(group, point, ctx))
-               {
-               ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_POINT_IS_NOT_ON_CURVE);
-               goto err;
-               }
-
-       ret = 1;
-       
- err:
-       BN_CTX_end(ctx);
-       if (new_ctx != NULL)
-               BN_CTX_free(new_ctx);
-       return ret;
-       }
+                            const unsigned char *buf, size_t len, BN_CTX *ctx)
+{
+    point_conversion_form_t form;
+    int y_bit;
+    BN_CTX *new_ctx = NULL;
+    BIGNUM *x, *y;
+    size_t field_len, enc_len;
+    int ret = 0;
+
+    if (len == 0) {
+        ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_BUFFER_TOO_SMALL);
+        return 0;
+    }
+    form = buf[0];
+    y_bit = form & 1;
+    form = form & ~1U;
+    if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED)
+        && (form != POINT_CONVERSION_UNCOMPRESSED)
+        && (form != POINT_CONVERSION_HYBRID)) {
+        ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
+        return 0;
+    }
+    if ((form == 0 || form == POINT_CONVERSION_UNCOMPRESSED) && y_bit) {
+        ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
+        return 0;
+    }
+
+    if (form == 0) {
+        if (len != 1) {
+            ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
+            return 0;
+        }
+
+        return EC_POINT_set_to_infinity(group, point);
+    }
+
+    field_len = BN_num_bytes(&group->field);
+    enc_len =
+        (form ==
+         POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;
+
+    if (len != enc_len) {
+        ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
+        return 0;
+    }
+
+    if (ctx == NULL) {
+        ctx = new_ctx = BN_CTX_new();
+        if (ctx == NULL)
+            return 0;
+    }
+
+    BN_CTX_start(ctx);
+    x = BN_CTX_get(ctx);
+    y = BN_CTX_get(ctx);
+    if (y == NULL)
+        goto err;
+
+    if (!BN_bin2bn(buf + 1, field_len, x))
+        goto err;
+    if (BN_ucmp(x, &group->field) >= 0) {
+        ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
+        goto err;
+    }
+
+    if (form == POINT_CONVERSION_COMPRESSED) {
+        if (!EC_POINT_set_compressed_coordinates_GFp
+            (group, point, x, y_bit, ctx))
+            goto err;
+    } else {
+        if (!BN_bin2bn(buf + 1 + field_len, field_len, y))
+            goto err;
+        if (BN_ucmp(y, &group->field) >= 0) {
+            ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
+            goto err;
+        }
+        if (form == POINT_CONVERSION_HYBRID) {
+            if (y_bit != BN_is_odd(y)) {
+                ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
+                goto err;
+            }
+        }
+
+        if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx))
+            goto err;
+    }
+
+    /* test required by X9.62 */
+    if (!EC_POINT_is_on_curve(group, point, ctx)) {
+        ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_POINT_IS_NOT_ON_CURVE);
+        goto err;
+    }
+
+    ret = 1;
 
+ err:
+    BN_CTX_end(ctx);
+    if (new_ctx != NULL)
+        BN_CTX_free(new_ctx);
+    return ret;
+}