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Title "D2I_RSAPRIVATEKEY 3ossl"
D2I_RSAPRIVATEKEY 3ossl "2023-09-19" "3.0.11" "OpenSSL"
For nroff, turn off justification. Always turn off hyphenation; it makes
way too many mistakes in technical documents.
"NAME"
d2i_DSAPrivateKey, d2i_DSAPrivateKey_bio, d2i_DSAPrivateKey_fp, d2i_DSAPublicKey, d2i_DSA_PUBKEY, d2i_DSA_PUBKEY_bio, d2i_DSA_PUBKEY_fp, d2i_DSAparams, d2i_RSAPrivateKey, d2i_RSAPrivateKey_bio, d2i_RSAPrivateKey_fp, d2i_RSAPublicKey, d2i_RSAPublicKey_bio, d2i_RSAPublicKey_fp, d2i_RSA_PUBKEY, d2i_RSA_PUBKEY_bio, d2i_RSA_PUBKEY_fp, d2i_DHparams, d2i_DHparams_bio, d2i_DHparams_fp, d2i_ECParameters, d2i_ECPrivateKey, d2i_ECPrivateKey_bio, d2i_ECPrivateKey_fp, d2i_EC_PUBKEY, d2i_EC_PUBKEY_bio, d2i_EC_PUBKEY_fp, i2d_RSAPrivateKey, i2d_RSAPrivateKey_bio, i2d_RSAPrivateKey_fp, i2d_RSAPublicKey, i2d_RSAPublicKey_bio, i2d_RSAPublicKey_fp, i2d_RSA_PUBKEY, i2d_RSA_PUBKEY_bio, i2d_RSA_PUBKEY_fp, i2d_DHparams, i2d_DHparams_bio, i2d_DHparams_fp, i2d_DSAPrivateKey, i2d_DSAPrivateKey_bio, i2d_DSAPrivateKey_fp, i2d_DSAPublicKey, i2d_DSA_PUBKEY, i2d_DSA_PUBKEY_bio, i2d_DSA_PUBKEY_fp, i2d_DSAparams, i2d_ECParameters, i2d_ECPrivateKey, i2d_ECPrivateKey_bio, i2d_ECPrivateKey_fp, i2d_EC_PUBKEY, i2d_EC_PUBKEY_bio, i2d_EC_PUBKEY_fp \- DEPRECATED
"SYNOPSIS"
Header "SYNOPSIS" The following functions have been deprecated since OpenSSL 3.0, and can be hidden entirely by defining \s-1OPENSSL_API_COMPAT\s0 with a suitable version value, see openssl_user_macros\|(7):

.Vb 12 TYPE *d2i_TYPEPrivateKey(TYPE **a, const unsigned char **ppin, long length); TYPE *d2i_TYPEPrivateKey_bio(BIO *bp, TYPE **a); TYPE *d2i_TYPEPrivateKey_fp(FILE *fp, TYPE **a); TYPE *d2i_TYPEPublicKey(TYPE **a, const unsigned char **ppin, long length); TYPE *d2i_TYPEPublicKey_bio(BIO *bp, TYPE **a); TYPE *d2i_TYPEPublicKey_fp(FILE *fp, TYPE **a); TYPE *d2i_TYPEparams(TYPE **a, const unsigned char **ppin, long length); TYPE *d2i_TYPEparams_bio(BIO *bp, TYPE **a); TYPE *d2i_TYPEparams_fp(FILE *fp, TYPE **a); TYPE *d2i_TYPE_PUBKEY(TYPE **a, const unsigned char **ppin, long length); TYPE *d2i_TYPE_PUBKEY_bio(BIO *bp, TYPE **a); TYPE *d2i_TYPE_PUBKEY_fp(FILE *fp, TYPE **a); \& int i2d_TYPEPrivateKey(const TYPE *a, unsigned char **ppout); int i2d_TYPEPrivateKey(TYPE *a, unsigned char **ppout); int i2d_TYPEPrivateKey_fp(FILE *fp, const TYPE *a); int i2d_TYPEPrivateKey_fp(FILE *fp, TYPE *a); int i2d_TYPEPrivateKey_bio(BIO *bp, const TYPE *a); int i2d_TYPEPrivateKey_bio(BIO *bp, TYPE *a); int i2d_TYPEPublicKey(const TYPE *a, unsigned char **ppout); int i2d_TYPEPublicKey(TYPE *a, unsigned char **ppout); int i2d_TYPEPublicKey_fp(FILE *fp, const TYPE *a); int i2d_TYPEPublicKey_fp(FILE *fp, TYPE *a); int i2d_TYPEPublicKey_bio(BIO *bp, const TYPE *a); int i2d_TYPEPublicKey_bio(BIO *bp, TYPE *a); int i2d_TYPEparams(const TYPE *a, unsigned char **ppout); int i2d_TYPEparams(TYPE *a, unsigned char **ppout); int i2d_TYPEparams_fp(FILE *fp, const TYPE *a); int i2d_TYPEparams_fp(FILE *fp, TYPE *a); int i2d_TYPEparams_bio(BIO *bp, const TYPE *a); int i2d_TYPEparams_bio(BIO *bp, TYPE *a); int i2d_TYPE_PUBKEY(const TYPE *a, unsigned char **ppout); int i2d_TYPE_PUBKEY(TYPE *a, unsigned char **ppout); int i2d_TYPE_PUBKEY_fp(FILE *fp, const TYPE *a); int i2d_TYPE_PUBKEY_fp(FILE *fp, TYPE *a); int i2d_TYPE_PUBKEY_bio(BIO *bp, const TYPE *a); int i2d_TYPE_PUBKEY_bio(BIO *bp, TYPE *a); .Ve

"DESCRIPTION"
Header "DESCRIPTION" All functions described here are deprecated. Please use \s-1OSSL_DECODER\s0\|(3) instead of the d2i functions and \s-1OSSL_ENCODER\s0\|(3) instead of the i2d functions. See \*(L"Migration\*(R" below.

In the description here, \f(BI\s-1TYPE\s0 is used a placeholder for any of the OpenSSL datatypes, such as \s-1RSA\s0. The function parameters ppin and ppout are generally either both named \fIpp in the headers, or in and out.

All the functions here behave the way that's described in d2i_X509\|(3).

Please note that not all functions in the synopsis are available for all key types. For example, there are no d2i_RSAparams() or i2d_RSAparams(), because the PKCS#1 \s-1RSA\s0 structure doesn't include any key parameters.

\fBd2i_\f(BI\s-1TYPE\s0PrivateKey() and derivates thereof decode \s-1DER\s0 encoded \fB\f(BI\s-1TYPE\s0 private key data organized in a type specific structure.

\fBd2i_\f(BI\s-1TYPE\s0PublicKey() and derivates thereof decode \s-1DER\s0 encoded \fB\f(BI\s-1TYPE\s0 public key data organized in a type specific structure.

\fBd2i_\f(BI\s-1TYPE\s0params() and derivates thereof decode \s-1DER\s0 encoded \f(BI\s-1TYPE\s0 key parameters organized in a type specific structure.

\fBd2i_\f(BI\s-1TYPE\s0_PUBKEY() and derivates thereof decode \s-1DER\s0 encoded \f(BI\s-1TYPE\s0 public key data organized in a SubjectPublicKeyInfo structure.

\fBi2d_\f(BI\s-1TYPE\s0PrivateKey() and derivates thereof encode the private key \fB\f(BI\s-1TYPE\s0 data into a type specific \s-1DER\s0 encoded structure.

\fBi2d_\f(BI\s-1TYPE\s0PublicKey() and derivates thereof encode the public key \fB\f(BI\s-1TYPE\s0 data into a type specific \s-1DER\s0 encoded structure.

\fBi2d_\f(BI\s-1TYPE\s0params() and derivates thereof encode the \f(BI\s-1TYPE\s0 key parameters data into a type specific \s-1DER\s0 encoded structure.

\fBi2d_\f(BI\s-1TYPE\s0_PUBKEY() and derivates thereof encode the public key \fB\f(BI\s-1TYPE\s0 data into a \s-1DER\s0 encoded SubjectPublicKeyInfo structure.

For example, d2i_RSAPrivateKey() and d2i_RSAPublicKey() expects the structure defined by PKCS#1. Similarly, i2d_RSAPrivateKey() and i2d_RSAPublicKey() produce \s-1DER\s0 encoded string organized according to PKCS#1.

"Migration"
Subsection "Migration" Migration from the diverse \f(BI\s-1TYPE\s0s requires using corresponding new OpenSSL types. For all \f(BI\s-1TYPE\s0s described here, the corresponding new type is \s-1EVP_PKEY\s0. The rest of this section assumes that this has been done, exactly how to do that is described elsewhere.

There are two migration paths:

"\(bu" 4
Replace b<d2i_\s-1TYPE\s0PrivateKey()> with d2i_PrivateKey\|(3), b<d2i_\s-1TYPE\s0PublicKey()> with d2i_PublicKey\|(3), b<d2i_\s-1TYPE\s0params()> with d2i_KeyParams\|(3), b<d2i_\s-1TYPE\s0_PUBKEY()> with d2i_PUBKEY\|(3), b<i2d_\s-1TYPE\s0PrivateKey()> with i2d_PrivateKey\|(3), b<i2d_\s-1TYPE\s0PublicKey()> with i2d_PublicKey\|(3), b<i2d_\s-1TYPE\s0params()> with i2d_KeyParams\|(3), b<i2d_\s-1TYPE\s0_PUBKEY()> with i2d_PUBKEY\|(3). A caveat is that i2d_PrivateKey\|(3) may output a \s-1DER\s0 encoded PKCS#8 outermost structure instead of the type specific structure, and that \fBd2i_PrivateKey\|(3) recognises and unpacks a PKCS#8 structures.
"\(bu" 4
Use \s-1OSSL_DECODER\s0\|(3) and \s-1OSSL_ENCODER\s0\|(3). How to migrate is described below. All those descriptions assume that the key to be encoded is in the variable pkey.

Migrating \f(BIi2d functions to \f(BI\s-1OSSL_ENCODER\s0 Subsection "Migrating i2d functions to OSSL_ENCODER"

The exact \s-1OSSL_ENCODER\s0\|(3) output is driven by arguments rather than by function names. The sample code to get \s-1DER\s0 encoded output in a type specific structure is uniform, the only things that vary are the selection of what part of the \s-1EVP_PKEY\s0 should be output, and the structure. The \fBi2d functions names can therefore be translated into two variables, \fIselection and structure as follows:

"i2d_\f(BI\s-1TYPE\s0PrivateKey() translates into:" 4
Item "i2d_TYPEPrivateKey() translates into:" .Vb 2 int selection = EVP_PKEY_KEYPAIR; const char *structure = "type-specific"; .Ve
"i2d_\f(BI\s-1TYPE\s0PublicKey() translates into:" 4
Item "i2d_TYPEPublicKey() translates into:" .Vb 2 int selection = EVP_PKEY_PUBLIC_KEY; const char *structure = "type-specific"; .Ve
"i2d_\f(BI\s-1TYPE\s0params() translates into:" 4
Item "i2d_TYPEparams() translates into:" .Vb 2 int selection = EVP_PKEY_PARAMETERS; const char *structure = "type-specific"; .Ve
"i2d_\f(BI\s-1TYPE\s0_PUBKEY() translates into:" 4
Item "i2d_TYPE_PUBKEY() translates into:" .Vb 2 int selection = EVP_PKEY_PUBLIC_KEY; const char *structure = "SubjectPublicKeyInfo"; .Ve

The following sample code does the rest of the work:

.Vb 10 unsigned char *p = buffer; /* |buffer| is supplied by the caller */ size_t len = buffer_size; /* assumed be the size of |buffer| */ OSSL_ENCODER_CTX *ctx = OSSL_ENCODER_CTX_new_for_pkey(pkey, selection, "DER", structure, NULL, NULL); if (ctx == NULL) { /* fatal error handling */ } if (OSSL_ENCODER_CTX_get_num_encoders(ctx) == 0) { OSSL_ENCODER_CTX_free(ctx); /* non-fatal error handling */ } if (!OSSL_ENCODER_to_data(ctx, &p, &len)) { OSSL_ENCODER_CTX_free(ctx); /* error handling */ } OSSL_ENCODER_CTX_free(ctx); .Ve

"NOTES"
Header "NOTES" The letters i and d in i2d_\f(BI\s-1TYPE\s0() stand for \*(L"internal\*(R" (that is, an internal C structure) and \*(L"\s-1DER\*(R"\s0 respectively. So i2d_\f(BI\s-1TYPE\s0() converts from internal to \s-1DER.\s0

The functions can also understand \s-1BER\s0 forms.

The actual \s-1TYPE\s0 structure passed to i2d_\f(BI\s-1TYPE\s0() must be a valid populated \f(BI\s-1TYPE\s0 structure \*(-- it cannot simply be fed with an empty structure such as that returned by TYPE_new().

The encoded data is in binary form and may contain embedded zeros. Therefore, any \s-1FILE\s0 pointers or BIOs should be opened in binary mode. Functions such as strlen() will not return the correct length of the encoded structure.

The ways that *ppin and *ppout are incremented after the operation can trap the unwary. See the \s-1WARNINGS\s0 section in d2i_X509\|(3) for some common errors. The reason for this-auto increment behaviour is to reflect a typical usage of \s-1ASN1\s0 functions: after one structure is encoded or decoded another will be processed after it.

The following points about the data types might be useful:

"\s-1DSA_PUBKEY\s0" 4
Item "DSA_PUBKEY" Represents a \s-1DSA\s0 public key using a SubjectPublicKeyInfo structure.
"DSAPublicKey, DSAPrivateKey" 4
Item "DSAPublicKey, DSAPrivateKey" Use a non-standard OpenSSL format and should be avoided; use \s-1DSA_PUBKEY\s0, \fBPEM_write_PrivateKey\|(3), or similar instead.
"RETURN VALUES"
Header "RETURN VALUES" \fBd2i_\f(BI\s-1TYPE\s0(), d2i_\f(BI\s-1TYPE\s0_bio() and d2i_\f(BI\s-1TYPE\s0_fp() return a valid \fB\f(BI\s-1TYPE\s0 structure or \s-1NULL\s0 if an error occurs. If the \*(L"reuse\*(R" capability has been used with a valid structure being passed in via a, then the object is freed in the event of error and *a is set to \s-1NULL.\s0

\fBi2d_\f(BI\s-1TYPE\s0() returns the number of bytes successfully encoded or a negative value if an error occurs.

\fBi2d_\f(BI\s-1TYPE\s0_bio() and i2d_\f(BI\s-1TYPE\s0_fp() return 1 for success and 0 if an error occurs.

"SEE ALSO"
Header "SEE ALSO" \s-1OSSL_ENCODER\s0\|(3), \s-1OSSL_DECODER\s0\|(3), \fBd2i_PrivateKey\|(3), d2i_PublicKey\|(3), d2i_KeyParams\|(3), \fBd2i_PUBKEY\|(3), \fBi2d_PrivateKey\|(3), i2d_PublicKey\|(3), i2d_KeyParams\|(3), \fBi2d_PUBKEY\|(3)
"COPYRIGHT"
Header "COPYRIGHT" Copyright 2020-2023 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the \*(L"License\*(R"). You may not use this file except in compliance with the License. You can obtain a copy in the file \s-1LICENSE\s0 in the source distribution or at <https://www.openssl.org/source/license.html>.