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Title "OPENSSL-PKEYUTL 1ossl" For nroff, turn off justification. Always turn off hyphenation; it makes
way too many mistakes in technical documents.
openssl-pkeyutl - public key algorithm command Header "SYNOPSIS" \fBopenssl pkeyutl [-help] [-in file] [-rawin] [-digest algorithm] [-out file] [-sigfile file] [-inkey filename|uri] [-keyform \s-1DER\s0|\s-1PEM\s0|P12|\s-1ENGINE\s0] [-passin arg] [-peerkey file] [-peerform \s-1DER\s0|\s-1PEM\s0|P12|\s-1ENGINE\s0] [-pubin] [-certin] [-rev] [-sign] [-verify] [-verifyrecover] [-encrypt] [-decrypt] [-derive] [-kdf algorithm] [-kdflen length] [-pkeyopt opt:value] [-pkeyopt_passin opt[:passarg]] [-hexdump] [-asn1parse] [-engine id] [-engine_impl] [-rand files] [-writerand file] [-provider name] [-provider-path path] [-propquery propq] [-config configfile] Header "DESCRIPTION" This command can be used to perform low-level public key operations using any supported algorithm. Header "OPTIONS" Item "-help" Print out a usage message. Item "-in filename" This specifies the input filename to read data from or standard input if this option is not specified. Item "-rawin" This indicates that the input data is raw data, which is not hashed by any message digest algorithm. The user can specify a digest algorithm by using the -digest option. This option can only be used with -sign and \fB-verify and must be used with the Ed25519 and Ed448 algorithms. Item "-digest algorithm" This specifies the digest algorithm which is used to hash the input data before signing or verifying it with the input key. This option could be omitted if the signature algorithm does not require one (for instance, EdDSA). If this option is omitted but the signature algorithm requires one, a default value will be used. For signature algorithms like \s-1RSA, DSA\s0 and \s-1ECDSA, SHA-256\s0 will be the default digest algorithm. For \s-1SM2,\s0 it will be \s-1SM3.\s0 If this option is present, then the -rawin option must be also specified. Item "-out filename" Specifies the output filename to write to or standard output by default. Item "-sigfile file" Signature file, required for -verify operations only Item "-inkey filename|uri" The input key, by default it should be a private key. Item "-keyform DER|PEM|P12|ENGINE" The key format; unspecified by default. See openssl-format-options\|(1) for details. Item "-passin arg" The input key password source. For more information about the format of arg see openssl-passphrase-options\|(1). Item "-peerkey file" The peer key file, used by key derivation (agreement) operations. Item "-peerform DER|PEM|P12|ENGINE" The peer key format; unspecified by default. See openssl-format-options\|(1) for details. Item "-pubin" The input file is a public key. Item "-certin" The input is a certificate containing a public key. Item "-rev" Reverse the order of the input buffer. This is useful for some libraries (such as CryptoAPI) which represent the buffer in little endian format. Item "-sign" Sign the input data (which must be a hash) and output the signed result. This requires a private key. Item "-verify" Verify the input data (which must be a hash) against the signature file and indicate if the verification succeeded or failed. Item "-verifyrecover" Verify the input data (which must be a hash) and output the recovered data. Item "-encrypt" Encrypt the input data using a public key. Item "-decrypt" Decrypt the input data using a private key. Item "-derive" Derive a shared secret using the peer key. Item "-kdf algorithm" Use key derivation function algorithm. The supported algorithms are at present \s-1TLS1-PRF\s0 and \s-1HKDF\s0. Note: additional parameters and the \s-1KDF\s0 output length will normally have to be set for this to work. See EVP_PKEY_CTX_set_hkdf_md\|(3) and EVP_PKEY_CTX_set_tls1_prf_md\|(3) for the supported string parameters of each algorithm. Item "-kdflen length" Set the output length for \s-1KDF.\s0 Item "-pkeyopt opt:value" Public key options specified as opt:value. See \s-1NOTES\s0 below for more details. Item "-pkeyopt_passin opt[:passarg]" Allows reading a public key option opt from stdin or a password source. If only opt is specified, the user will be prompted to enter a password on stdin. Alternatively, passarg can be specified which can be any value supported by openssl-passphrase-options\|(1). Item "-hexdump" hex dump the output data. Item "-asn1parse" Parse the \s-1ASN.1\s0 output data, this is useful when combined with the \fB-verifyrecover option when an \s-1ASN1\s0 structure is signed. Item "-engine id" See \*(L"Engine Options\*(R" in openssl\|(1). This option is deprecated. Item "-engine_impl" When used with the -engine option, it specifies to also use engine id for crypto operations. Item "-rand files, -writerand file" See \*(L"Random State Options\*(R" in openssl\|(1) for details. Item "-provider name"

0

Item "-provider-path path" Item "-propquery propq"

See \*(L"Provider Options\*(R" in openssl\|(1), provider\|(7), and property\|(7).

Item "-config configfile" See \*(L"Configuration Option\*(R" in openssl\|(1). Header "NOTES" The operations and options supported vary according to the key algorithm and its implementation. The OpenSSL operations and options are indicated below.

Unless otherwise mentioned all algorithms support the digest:alg option which specifies the digest in use for sign, verify and verifyrecover operations. The value alg should represent a digest name as used in the \fBEVP_get_digestbyname() function for example sha1. This value is not used to hash the input data. It is used (by some algorithms) for sanity-checking the lengths of data passed in and for creating the structures that make up the signature (e.g. DigestInfo in \s-1RSASSA\s0 PKCS#1 v1.5 signatures).

This command does not hash the input data (except where -rawin is used) but rather it will use the data directly as input to the signature algorithm. Depending on the key type, signature type, and mode of padding, the maximum acceptable lengths of input data differ. The signed data can't be longer than the key modulus with \s-1RSA.\s0 In case of \s-1ECDSA\s0 and \s-1DSA\s0 the data shouldn't be longer than the field size, otherwise it will be silently truncated to the field size. In any event the input size must not be larger than the largest supported digest size.

In other words, if the value of digest is sha1 the input should be the 20 bytes long binary encoding of the \s-1SHA-1\s0 hash function output.

Header "RSA ALGORITHM" The \s-1RSA\s0 algorithm generally supports the encrypt, decrypt, sign, verify and verifyrecover operations. However, some padding modes support only a subset of these operations. The following additional \fBpkeyopt values are supported: Item "rsa_padding_mode:mode" This sets the \s-1RSA\s0 padding mode. Acceptable values for mode are pkcs1 for PKCS#1 padding, none for no padding, oaep for \s-1OAEP\s0 mode, x931 for X9.31 mode and pss for \s-1PSS.\s0 .Sp In PKCS#1 padding if the message digest is not set then the supplied data is signed or verified directly instead of using a DigestInfo structure. If a digest is set then the a DigestInfo structure is used and its the length must correspond to the digest type. .Sp For oaep mode only encryption and decryption is supported. .Sp For x931 if the digest type is set it is used to format the block data otherwise the first byte is used to specify the X9.31 digest \s-1ID.\s0 Sign, verify and verifyrecover are can be performed in this mode. .Sp For pss mode only sign and verify are supported and the digest type must be specified. Item "rsa_pss_saltlen:len" For pss mode only this option specifies the salt length. Three special values are supported: digest sets the salt length to the digest length, \fBmax sets the salt length to the maximum permissible value. When verifying \fBauto causes the salt length to be automatically determined based on the \fB\s-1PSS\s0 block structure. Item "rsa_mgf1_md:digest" For \s-1PSS\s0 and \s-1OAEP\s0 padding sets the \s-1MGF1\s0 digest. If the \s-1MGF1\s0 digest is not explicitly set in \s-1PSS\s0 mode then the signing digest is used. Item "rsa_oaep_md:digest" Sets the digest used for the \s-1OAEP\s0 hash function. If not explicitly set then \s-1SHA1\s0 is used. Header "RSA-PSS ALGORITHM" The RSA-PSS algorithm is a restricted version of the \s-1RSA\s0 algorithm which only supports the sign and verify operations with \s-1PSS\s0 padding. The following additional -pkeyopt values are supported: Item "rsa_padding_mode:mode, rsa_pss_saltlen:len, rsa_mgf1_md:digest" These have the same meaning as the \s-1RSA\s0 algorithm with some additional restrictions. The padding mode can only be set to pss which is the default value. .Sp If the key has parameter restrictions than the digest, \s-1MGF1\s0 digest and salt length are set to the values specified in the parameters. The digest and \s-1MG\s0 cannot be changed and the salt length cannot be set to a value less than the minimum restriction. Header "DSA ALGORITHM" The \s-1DSA\s0 algorithm supports signing and verification operations only. Currently there are no additional -pkeyopt options other than digest. The \s-1SHA1\s0 digest is assumed by default. Header "DH ALGORITHM" The \s-1DH\s0 algorithm only supports the derivation operation and no additional \fB-pkeyopt options. Header "EC ALGORITHM" The \s-1EC\s0 algorithm supports sign, verify and derive operations. The sign and verify operations use \s-1ECDSA\s0 and derive uses \s-1ECDH. SHA1\s0 is assumed by default for the -pkeyopt digest option. Header "X25519 AND X448 ALGORITHMS" The X25519 and X448 algorithms support key derivation only. Currently there are no additional options. Header "ED25519 AND ED448 ALGORITHMS" These algorithms only support signing and verifying. OpenSSL only implements the \*(L"pure\*(R" variants of these algorithms so raw data can be passed directly to them without hashing them first. The option -rawin must be used with these algorithms with no -digest specified. Additionally OpenSSL only supports \*(L"oneshot\*(R" operation with these algorithms. This means that the entire file to be signed/verified must be read into memory before processing it. Signing or Verifying very large files should be avoided. Additionally the size of the file must be known for this to work. If the size of the file cannot be determined (for example if the input is stdin) then the sign or verify operation will fail. Header "SM2" The \s-1SM2\s0 algorithm supports sign, verify, encrypt and decrypt operations. For the sign and verify operations, \s-1SM2\s0 requires an Distinguishing \s-1ID\s0 string to be passed in. The following -pkeyopt value is supported: Item "distid:string" This sets the \s-1ID\s0 string used in \s-1SM2\s0 sign or verify operations. While verifying an \s-1SM2\s0 signature, the \s-1ID\s0 string must be the same one used when signing the data. Otherwise the verification will fail. Item "hexdistid:hex_string" This sets the \s-1ID\s0 string used in \s-1SM2\s0 sign or verify operations. While verifying an \s-1SM2\s0 signature, the \s-1ID\s0 string must be the same one used when signing the data. Otherwise the verification will fail. The \s-1ID\s0 string provided with this option should be a valid hexadecimal value. Header "EXAMPLES" Sign some data using a private key:

.Vb 1 openssl pkeyutl -sign -in file -inkey key.pem -out sig .Ve

Recover the signed data (e.g. if an \s-1RSA\s0 key is used):

.Vb 1 openssl pkeyutl -verifyrecover -in sig -inkey key.pem .Ve

Verify the signature (e.g. a \s-1DSA\s0 key):

.Vb 1 openssl pkeyutl -verify -in file -sigfile sig -inkey key.pem .Ve

Sign data using a message digest value (this is currently only valid for \s-1RSA\s0):

.Vb 1 openssl pkeyutl -sign -in file -inkey key.pem -out sig -pkeyopt digest:sha256 .Ve

Derive a shared secret value:

.Vb 1 openssl pkeyutl -derive -inkey key.pem -peerkey pubkey.pem -out secret .Ve

Hexdump 48 bytes of \s-1TLS1 PRF\s0 using digest \s-1SHA256\s0 and shared secret and seed consisting of the single byte 0xFF:

.Vb 2 openssl pkeyutl -kdf TLS1-PRF -kdflen 48 -pkeyopt md:SHA256 \e -pkeyopt hexsecret:ff -pkeyopt hexseed:ff -hexdump .Ve

Derive a key using scrypt where the password is read from command line:

.Vb 2 openssl pkeyutl -kdf scrypt -kdflen 16 -pkeyopt_passin pass \e -pkeyopt hexsalt:aabbcc -pkeyopt N:16384 -pkeyopt r:8 -pkeyopt p:1 .Ve

Derive using the same algorithm, but read key from environment variable \s-1MYPASS:\s0

.Vb 2 openssl pkeyutl -kdf scrypt -kdflen 16 -pkeyopt_passin pass:env:MYPASS \e -pkeyopt hexsalt:aabbcc -pkeyopt N:16384 -pkeyopt r:8 -pkeyopt p:1 .Ve

Sign some data using an \s-1SM2\s0\|(7) private key and a specific \s-1ID:\s0

.Vb 2 openssl pkeyutl -sign -in file -inkey sm2.key -out sig -rawin -digest sm3 \e -pkeyopt distid:someid .Ve

Verify some data using an \s-1SM2\s0\|(7) certificate and a specific \s-1ID:\s0

.Vb 2 openssl pkeyutl -verify -certin -in file -inkey sm2.cert -sigfile sig \e -rawin -digest sm3 -pkeyopt distid:someid .Ve

Decrypt some data using a private key with \s-1OAEP\s0 padding using \s-1SHA256:\s0

.Vb 2 openssl pkeyutl -decrypt -in file -inkey key.pem -out secret \e -pkeyopt rsa_padding_mode:oaep -pkeyopt rsa_oaep_md:sha256 .Ve

Header "SEE ALSO" \fBopenssl\|(1), \fBopenssl-genpkey\|(1), \fBopenssl-pkey\|(1), \fBopenssl-rsautl\|(1) \fBopenssl-dgst\|(1), \fBopenssl-rsa\|(1), \fBopenssl-genrsa\|(1), \fBopenssl-kdf\|(1) \fBEVP_PKEY_CTX_set_hkdf_md\|(3), \fBEVP_PKEY_CTX_set_tls1_prf_md\|(3), Header "HISTORY" The -engine option was deprecated in OpenSSL 3.0. Header "COPYRIGHT" Copyright 2006-2021 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>.