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diff --git a/lib/crypto/doc/src/crypto.xml b/lib/crypto/doc/src/crypto.xml new file mode 100644 index 0000000000..42ba523c8c --- /dev/null +++ b/lib/crypto/doc/src/crypto.xml @@ -0,0 +1,785 @@ +<?xml version="1.0" encoding="latin1" ?> +<!DOCTYPE erlref SYSTEM "erlref.dtd"> + +<erlref> + <header> + <copyright> + <year>1999</year><year>2009</year> + <holder>Ericsson AB. All Rights Reserved.</holder> + </copyright> + <legalnotice> + The contents of this file are subject to the Erlang Public License, + Version 1.1, (the "License"); you may not use this file except in + compliance with the License. You should have received a copy of the + Erlang Public License along with this software. If not, it can be + retrieved online at http://www.erlang.org/. + + Software distributed under the License is distributed on an "AS IS" + basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See + the License for the specific language governing rights and limitations + under the License. + + </legalnotice> + + <title>crypto</title> + <prepared>Peter Högfeldt</prepared> + <docno></docno> + <date>2000-06-20</date> + <rev>B</rev> + </header> + <module>crypto</module> + <modulesummary>Crypto Functions</modulesummary> + <description> + <p>This module provides a set of cryptographic functions. + </p> + <p>References:</p> + <list type="bulleted"> + <item> + <p>md5: The MD5 Message Digest Algorithm (RFC 1321)</p> + </item> + <item> + <p>sha: Secure Hash Standard (FIPS 180-2)</p> + </item> + <item> + <p>hmac: Keyed-Hashing for Message Authentication (RFC 2104)</p> + </item> + <item> + <p>des: Data Encryption Standard (FIPS 46-3)</p> + </item> + <item> + <p>aes: Advanced Encryption Standard (AES) (FIPS 197) </p> + </item> + <item> + <p>ecb, cbc, cfb, ofb: Recommendation for Block Cipher Modes + of Operation (NIST SP 800-38A).</p> + </item> + <item> + <p>rsa: Recommendation for Block Cipher Modes of Operation + (NIST 800-38A)</p> + </item> + <item> + <p>dss: Digital Signature Standard (FIPS 186-2)</p> + </item> + </list> + <p>The above publications can be found at <url href="http://csrc.nist.gov/publications">NIST publications</url>, at <url href="http://www.ietf.org">IETF</url>. + </p> + <p><em>Types</em></p> + <pre> +byte() = 0 ... 255 +ioelem() = byte() | binary() | iolist() +iolist() = [ioelem()] +Mpint() = <![CDATA[<<ByteLen:32/integer-big, Bytes:ByteLen/binary>>]]> + </pre> + <p></p> + </description> + <funcs> + <func> + <name>start() -> ok</name> + <fsummary>Start the crypto server.</fsummary> + <desc> + <p>Starts the crypto server.</p> + </desc> + </func> + <func> + <name>stop() -> ok</name> + <fsummary>Stop the crypto server.</fsummary> + <desc> + <p>Stops the crypto server.</p> + </desc> + </func> + <func> + <name>info() -> [atom()]</name> + <fsummary>Provide a list of available crypto functions.</fsummary> + <desc> + <p>Provides the available crypto functions in terms of a list + of atoms.</p> + </desc> + </func> + <func> + <name>info_lib() -> [{Name,VerNum,VerStr}]</name> + <fsummary>Provides information about the libraries used by crypto.</fsummary> + <type> + <v>Name = binary()</v> + <v>VerNum = integer()</v> + <v>VerStr = binary()</v> + </type> + <desc> + <p>Provides the name and version of the libraries used by crypto.</p> + <p><c>Name</c> is the name of the library. <c>VerNum</c> is + the numeric version according to the library's own versioning + scheme. <c>VerStr</c> contains a text variant of the version.</p> + <pre> +> <input>info_lib().</input> +[{<<"OpenSSL">>,9469983,<<"OpenSSL 0.9.8a 11 Oct 2005">>}] + </pre> + </desc> + </func> + <func> + <name>md5(Data) -> Digest</name> + <fsummary>Compute an <c>MD5</c>message digest from <c>Data</c></fsummary> + <type> + <v>Data = iolist() | binary()</v> + <v>Digest = binary()</v> + </type> + <desc> + <p>Computes an <c>MD5</c> message digest from <c>Data</c>, where + the length of the digest is 128 bits (16 bytes).</p> + </desc> + </func> + <func> + <name>md5_init() -> Context</name> + <fsummary>Creates an MD5 context</fsummary> + <type> + <v>Context = binary()</v> + </type> + <desc> + <p>Creates an MD5 context, to be used in subsequent calls to + <c>md5_update/2</c>.</p> + </desc> + </func> + <func> + <name>md5_update(Context, Data) -> NewContext</name> + <fsummary>Update an MD5 <c>Context</c>with <c>Data</c>, and return a <c>NewContext</c></fsummary> + <type> + <v>Data = iolist() | binary()</v> + <v>Context = NewContext = binary()</v> + </type> + <desc> + <p>Updates an MD5 <c>Context</c> with <c>Data</c>, and returns + a <c>NewContext</c>.</p> + </desc> + </func> + <func> + <name>md5_final(Context) -> Digest</name> + <fsummary>Finish the update of an MD5 <c>Context</c>and return the computed <c>MD5</c>message digest</fsummary> + <type> + <v>Context = Digest = binary()</v> + </type> + <desc> + <p>Finishes the update of an MD5 <c>Context</c> and returns + the computed <c>MD5</c> message digest.</p> + </desc> + </func> + <func> + <name>sha(Data) -> Digest</name> + <fsummary>Compute an <c>SHA</c>message digest from <c>Data</c></fsummary> + <type> + <v>Data = iolist() | binary()</v> + <v>Digest = binary()</v> + </type> + <desc> + <p>Computes an <c>SHA</c> message digest from <c>Data</c>, where + the length of the digest is 160 bits (20 bytes).</p> + </desc> + </func> + <func> + <name>sha_init() -> Context</name> + <fsummary>Create an SHA context</fsummary> + <type> + <v>Context = binary()</v> + </type> + <desc> + <p>Creates an SHA context, to be used in subsequent calls to + <c>sha_update/2</c>.</p> + </desc> + </func> + <func> + <name>sha_update(Context, Data) -> NewContext</name> + <fsummary>Update an SHA context</fsummary> + <type> + <v>Data = iolist() | binary()</v> + <v>Context = NewContext = binary()</v> + </type> + <desc> + <p>Updates an SHA <c>Context</c> with <c>Data</c>, and returns + a <c>NewContext</c>.</p> + </desc> + </func> + <func> + <name>sha_final(Context) -> Digest</name> + <fsummary>Finish the update of an SHA context</fsummary> + <type> + <v>Context = Digest = binary()</v> + </type> + <desc> + <p>Finishes the update of an SHA <c>Context</c> and returns + the computed <c>SHA</c> message digest.</p> + </desc> + </func> + <func> + <name>md5_mac(Key, Data) -> Mac</name> + <fsummary>Compute an <c>MD5 MAC</c>message authentification code</fsummary> + <type> + <v>Key = Data = iolist() | binary()</v> + <v>Mac = binary()</v> + </type> + <desc> + <p>Computes an <c>MD5 MAC</c> message authentification code + from <c>Key</c> and <c>Data</c>, where the the length of the + Mac is 128 bits (16 bytes).</p> + </desc> + </func> + <func> + <name>md5_mac_96(Key, Data) -> Mac</name> + <fsummary>Compute an <c>MD5 MAC</c>message authentification code</fsummary> + <type> + <v>Key = Data = iolist() | binary()</v> + <v>Mac = binary()</v> + </type> + <desc> + <p>Computes an <c>MD5 MAC</c> message authentification code + from <c>Key</c> and <c>Data</c>, where the length of the Mac + is 96 bits (12 bytes).</p> + </desc> + </func> + <func> + <name>sha_mac(Key, Data) -> Mac</name> + <fsummary>Compute an <c>MD5 MAC</c>message authentification code</fsummary> + <type> + <v>Key = Data = iolist() | binary()</v> + <v>Mac = binary()</v> + </type> + <desc> + <p>Computes an <c>SHA MAC</c> message authentification code + from <c>Key</c> and <c>Data</c>, where the length of the Mac + is 160 bits (20 bytes).</p> + </desc> + </func> + <func> + <name>sha_mac_96(Key, Data) -> Mac</name> + <fsummary>Compute an <c>MD5 MAC</c>message authentification code</fsummary> + <type> + <v>Key = Data = iolist() | binary()</v> + <v>Mac = binary()</v> + </type> + <desc> + <p>Computes an <c>SHA MAC</c> message authentification code + from <c>Key</c> and <c>Data</c>, where the length of the Mac + is 96 bits (12 bytes).</p> + </desc> + </func> + <func> + <name>des_cbc_encrypt(Key, IVec, Text) -> Cipher</name> + <fsummary>Encrypt <c>Text</c>according to DES in CBC mode</fsummary> + <type> + <v>Key = Text = iolist() | binary()</v> + <v>IVec = Cipher = binary()</v> + </type> + <desc> + <p>Encrypts <c>Text</c> according to DES in CBC + mode. <c>Text</c> must be a multiple of 64 bits (8 + bytes). <c>Key</c> is the DES key, and <c>IVec</c> is an + arbitrary initializing vector. The lengths of <c>Key</c> and + <c>IVec</c> must be 64 bits (8 bytes).</p> + </desc> + </func> + <func> + <name>des_cbc_decrypt(Key, IVec, Cipher) -> Text</name> + <fsummary>Decrypt <c>Cipher</c>according to DES in CBC mode</fsummary> + <type> + <v>Key = Cipher = iolist() | binary()</v> + <v>IVec = Text = binary()</v> + </type> + <desc> + <p>Decrypts <c>Cipher</c> according to DES in CBC mode. + <c>Key</c> is the DES key, and <c>IVec</c> is an arbitrary + initializing vector. <c>Key</c> and <c>IVec</c> must have + the same values as those used when encrypting. <c>Cipher</c> + must be a multiple of 64 bits (8 bytes). The lengths of + <c>Key</c> and <c>IVec</c> must be 64 bits (8 bytes).</p> + </desc> + </func> + <func> + <name>des_cbc_ivec(Data) -> IVec</name> + <fsummary>Get <c>IVec</c> to be used in next iteration of + <c>des_cbc_[ecrypt|decrypt]</c></fsummary> + <type> + <v>Data = iolist() | binary()</v> + <v>IVec = binary()</v> + </type> + <desc> + <p>Returns the <c>IVec</c> to be used in a next iteration of + <c>des_cbc_[encrypt|decrypt]</c>. <c>Data</c> is the encrypted + data from the previous iteration step.</p> + </desc> + </func> + <func> + <name>des3_cbc_encrypt(Key1, Key2, Key3, IVec, Text) -> Cipher</name> + <fsummary>Encrypt <c>Text</c>according to DES3 in CBC mode</fsummary> + <type> + <v>Key1 =Key2 = Key3 Text = iolist() | binary()</v> + <v>IVec = Cipher = binary()</v> + </type> + <desc> + <p>Encrypts <c>Text</c> according to DES3 in CBC + mode. <c>Text</c> must be a multiple of 64 bits (8 + bytes). <c>Key1</c>, <c>Key2</c>, <c>Key3</c>, are the DES + keys, and <c>IVec</c> is an arbitrary initializing + vector. The lengths of each of <c>Key1</c>, <c>Key2</c>, + <c>Key3</c> and <c>IVec</c> must be 64 bits (8 bytes).</p> + </desc> + </func> + <func> + <name>des3_cbc_decrypt(Key1, Key2, Key3, IVec, Cipher) -> Text</name> + <fsummary>Decrypt <c>Cipher</c>according to DES in CBC mode</fsummary> + <type> + <v>Key1 = Key2 = Key3 = Cipher = iolist() | binary()</v> + <v>IVec = Text = binary()</v> + </type> + <desc> + <p>Decrypts <c>Cipher</c> according to DES3 in CBC mode. + <c>Key1</c>, <c>Key2</c>, <c>Key3</c> are the DES key, and + <c>IVec</c> is an arbitrary initializing vector. + <c>Key1</c>, <c>Key2</c>, <c>Key3</c> and <c>IVec</c> must + and <c>IVec</c> must have the same values as those used when + encrypting. <c>Cipher</c> must be a multiple of 64 bits (8 + bytes). The lengths of <c>Key1</c>, <c>Key2</c>, + <c>Key3</c>, and <c>IVec</c> must be 64 bits (8 bytes).</p> + </desc> + </func> + <func> + <name>blowfish_cfb64_encrypt(Key, IVec, Text) -> Cipher</name> + <fsummary>Encrypt <c>Text</c>using Blowfish in CFB mode with 64 + bit feedback</fsummary> + <type> + <v>Key = Text = iolist() | binary()</v> + <v>IVec = Cipher = binary()</v> + </type> + <desc> + <p>Encrypts <c>Text</c> using Blowfish in CFB mode with 64 bit + feedback. <c>Key</c> is the Blowfish key, and <c>IVec</c> is an + arbitrary initializing vector. The length of <c>IVec</c> + must be 64 bits (8 bytes).</p> + </desc> + </func> + <func> + <name>blowfish_cfb64_decrypt(Key, IVec, Text) -> Cipher</name> + <fsummary>Decrypt <c>Text</c>using Blowfish in CFB mode with 64 + bit feedback</fsummary> + <type> + <v>Key = Text = iolist() | binary()</v> + <v>IVec = Cipher = binary()</v> + </type> + <desc> + <p>Decrypts <c>Text</c> using Blowfish in CFB mode with 64 bit + feedback. <c>Key</c> is the Blowfish key, and <c>IVec</c> is an + arbitrary initializing vector. The length of <c>IVec</c> + must be 64 bits (8 bytes).</p> + </desc> + </func> + <func> + <name>aes_cfb_128_encrypt(Key, IVec, Text) -> Cipher</name> + <name>aes_cbc_128_encrypt(Key, IVec, Text) -> Cipher</name> + <fsummary>Encrypt <c>Text</c>according to AES in Cipher Feedback mode or Cipher Block Chaining mode</fsummary> + <type> + <v>Key = Text = iolist() | binary()</v> + <v>IVec = Cipher = binary()</v> + </type> + <desc> + <p>Encrypts <c>Text</c> according to AES in Cipher Feedback + mode (CFB) or Cipher Block Chaining mode (CBC). <c>Text</c> + must be a multiple of 128 bits (16 bytes). <c>Key</c> is the + AES key, and <c>IVec</c> is an arbitrary initializing vector. + The lengths of <c>Key</c> and <c>IVec</c> must be 128 bits + (16 bytes).</p> + </desc> + </func> + <func> + <name>aes_cfb_128_decrypt(Key, IVec, Cipher) -> Text</name> + <name>aes_cbc_128_decrypt(Key, IVec, Cipher) -> Text</name> + <fsummary>Decrypt <c>Cipher</c>according to AES in Cipher Feedback mode or Cipher Block Chaining mode</fsummary> + <type> + <v>Key = Cipher = iolist() | binary()</v> + <v>IVec = Text = binary()</v> + </type> + <desc> + <p>Decrypts <c>Cipher</c> according to Cipher Feedback Mode (CFB) + or Cipher Block Chaining mode (CBC). + <c>Key</c> is the AES key, and <c>IVec</c> is an arbitrary + initializing vector. <c>Key</c> and <c>IVec</c> must have + the same values as those used when encrypting. <c>Cipher</c> + must be a multiple of 128 bits (16 bytes). The lengths of + <c>Key</c> and <c>IVec</c> must be 128 bits (16 bytes).</p> + </desc> + </func> + <func> + <name>aes_cbc_ivec(Data) -> IVec</name> + <fsummary>Get <c>IVec</c> to be used in next iteration of + <c>aes_cbc_*_[ecrypt|decrypt]</c></fsummary> + <type> + <v>Data = iolist() | binary()</v> + <v>IVec = binary()</v> + </type> + <desc> + <p>Returns the <c>IVec</c> to be used in a next iteration of + <c>aes_cbc_*_[encrypt|decrypt]</c>. <c>Data</c> is the encrypted + data from the previous iteration step.</p> + </desc> + </func> + <func> + <name>erlint(Mpint) -> N</name> + <name>mpint(N) -> Mpint</name> + <fsummary>Convert between binary multi-precision integer and erlang big integer</fsummary> + <type> + <v>Mpint = binary()</v> + <v>N = integer()</v> + </type> + <desc> + <p>Convert a binary multi-precision integer <c>Mpint</c> to and from + an erlang big integer. A multi-precision integer is a binary + with the following form: + <c><![CDATA[<<ByteLen:32/integer, Bytes:ByteLen/binary>>]]></c> where both + <c>ByteLen</c> and <c>Bytes</c> are big-endian. Mpints are used in + some of the functions in <c>crypto</c> and are not translated + in the API for performance reasons.</p> + </desc> + </func> + <func> + <name>rand_bytes(N) -> binary()</name> + <fsummary>Generate a binary of random bytes</fsummary> + <type> + <v>N = integer()</v> + </type> + <desc> + <p>Generates N bytes randomly uniform 0..255, and returns the + result in a binary. Uses the <c>crypto</c> library pseudo-random + number generator.</p> + </desc> + </func> + <func> + <name>rand_uniform(Lo, Hi) -> N</name> + <fsummary>Generate a random number</fsummary> + <type> + <v>Lo, Hi, N = Mpint | integer()</v> + <v>Mpint = binary()</v> + </type> + <desc> + <p>Generate a random number <c><![CDATA[N, Lo =< N < Hi.]]></c> Uses the + <c>crypto</c> library pseudo-random number generator. The + arguments (and result) can be either erlang integers or binary + multi-precision integers.</p> + </desc> + </func> + <func> + <name>mod_exp(N, P, M) -> Result</name> + <fsummary>Perform N ^ P mod M</fsummary> + <type> + <v>N, P, M, Result = Mpint</v> + <v>Mpint = binary()</v> + </type> + <desc> + <p>This function performs the exponentiation <c>N ^ P mod M</c>, + using the <c>crypto</c> library.</p> + </desc> + </func> + + <func> + <name>rsa_sign(Data, Key) -> Signature</name> + <name>rsa_sign(DigestType, Data, Key) -> Signature</name> + <fsummary>Sign the data using rsa with the given key.</fsummary> + <type> + <v>Data = Mpint</v> + <v>Key = [E, N, D]</v> + <v>E, N, D = Mpint</v> + <d>Where <c>E</c> is the public exponent, <c>N</c> is public modulus and + <c>D</c> is the private exponent.</d> + <v>DigestType = md5 | sha</v> + <d>The default <c>DigestType</c> is sha.</d> + <v>Mpint = binary()</v> + <v>Signature = binary()</v> + </type> + <desc> + <p>Calculates a <c>DigestType</c> digest of the <c>Data</c> + and creates a RSA signature with the private key <c>Key</c> + of the digest.</p> + </desc> + </func> + + <func> + <name>rsa_verify(Data, Signature, Key) -> Verified</name> + <name>rsa_verify(DigestType, Data, Signature, Key) -> Verified </name> + <fsummary>Verify the digest and signature using rsa with given public key.</fsummary> + <type> + <v>Verified = boolean()</v> + <v>Data, Signature = Mpint</v> + <v>Key = [E, N]</v> + <v>E, N = Mpint</v> + <d>Where <c>E</c> is the public exponent and <c>N</c> is public modulus.</d> + <v>DigestType = md5 | sha</v> + <d> The default <c>DigestType</c> is sha.</d> + <v>Mpint = binary()</v> + </type> + <desc> + <p>Calculates a <c>DigestType</c> digest of the <c>Data</c> + and verifies that the digest matches the RSA signature using the + signer's public key <c>Key</c>. + </p> + </desc> + </func> + + <func> + <name>rsa_public_encrypt(PlainText, PublicKey, Padding) -> ChipherText</name> + <fsummary>Encrypts Msg using the public Key.</fsummary> + <type> + <v>PlainText = binary()</v> + <v>PublicKey = [E, N]</v> + <v>E, N = Mpint</v> + <d>Where <c>E</c> is the public exponent and <c>N</c> is public modulus.</d> + <v>Padding = rsa_pkcs1_padding | rsa_pkcs1_oaep_padding | rsa_no_padding</v> + <v>ChipherText = binary()</v> + </type> + <desc> + <p>Encrypts the <c>PlainText</c> (usually a session key) using the <c>PublicKey</c> + and returns the cipher. The <c>Padding</c> decides what padding mode is used, + <c>rsa_pkcs1_padding</c> is PKCS #1 v1.5 currently the most + used mode and <c>rsa_pkcs1_oaep_padding</c> is EME-OAEP as + defined in PKCS #1 v2.0 with SHA-1, MGF1 and an empty encoding + parameter. This mode is recommended for all new applications. + The size of the <c>Msg</c> must be less + than <c>byte_size(N)-11</c> if + <c>rsa_pkcs1_padding</c> is used, <c>byte_size(N)-41</c> if + <c>rsa_pkcs1_oaep_padding</c> is used and <c>byte_size(N)</c> if <c>rsa_no_padding</c> + is used. + Where byte_size(N) is the size part of an <c>Mpint-1</c>. + </p> + </desc> + </func> + + <func> + <name>rsa_private_decrypt(ChipherText, PrivateKey, Padding) -> PlainText</name> + <fsummary>Decrypts ChipherText using the private Key.</fsummary> + <type> + <v>ChipherText = binary()</v> + <v>PrivateKey = [E, N, D]</v> + <v>E, N, D = Mpint</v> + <d>Where <c>E</c> is the public exponent, <c>N</c> is public modulus and + <c>D</c> is the private exponent.</d> + <v>Padding = rsa_pkcs1_padding | rsa_pkcs1_oaep_padding | rsa_no_padding</v> + <v>PlainText = binary()</v> + </type> + <desc> + <p>Decrypts the <c>ChipherText</c> (usually a session key encrypted with + <seealso marker="#rsa_public_encrypt/3">rsa_public_encrypt/3</seealso>) + using the <c>PrivateKey</c> and returns the + message. The <c>Padding</c> is the padding mode that was + used to encrypt the data, + see <seealso marker="#rsa_public_encrypt/3">rsa_public_encrypt/3</seealso>. + </p> + </desc> + </func> + <func> + <name>rsa_private_encrypt(PlainText, PrivateKey, Padding) -> ChipherText</name> + <fsummary>Encrypts Msg using the private Key.</fsummary> + <type> + <v>PlainText = binary()</v> + <v>PrivateKey = [E, N, D]</v> + <v>E, N, D = Mpint</v> + <d>Where <c>E</c> is the public exponent, <c>N</c> is public modulus and + <c>D</c> is the private exponent.</d> + <v>Padding = rsa_pkcs1_padding | rsa_no_padding</v> + <v>ChipherText = binary()</v> + </type> + <desc> + <p>Encrypts the <c>PlainText</c> using the <c>PrivateKey</c> + and returns the cipher. The <c>Padding</c> decides what padding mode is used, + <c>rsa_pkcs1_padding</c> is PKCS #1 v1.5 currently the most + used mode. + The size of the <c>Msg</c> must be less than <c>byte_size(N)-11</c> if + <c>rsa_pkcs1_padding</c> is used, and <c>byte_size(N)</c> if <c>rsa_no_padding</c> + is used. Where byte_size(N) is the size part of an <c>Mpint-1</c>. + </p> + </desc> + </func> + + <func> + <name>rsa_public_decrypt(ChipherText, PublicKey, Padding) -> PlainText</name> + <fsummary>Decrypts ChipherText using the public Key.</fsummary> + <type> + <v>ChipherText = binary()</v> + <v>PublicKey = [E, N]</v> + <v>E, N = Mpint</v> + <d>Where <c>E</c> is the public exponent and <c>N</c> is public modulus</d> + <v>Padding = rsa_pkcs1_padding | rsa_no_padding</v> + <v>PlainText = binary()</v> + </type> + <desc> + <p>Decrypts the <c>ChipherText</c> (encrypted with + <seealso marker="#rsa_private_encrypt/3">rsa_private_encrypt/3</seealso>) + using the <c>PrivateKey</c> and returns the + message. The <c>Padding</c> is the padding mode that was + used to encrypt the data, + see <seealso marker="#rsa_private_encrypt/3">rsa_private_encrypt/3</seealso>. + </p> + </desc> + </func> + + <func> + <name>dss_sign(Data, Key) -> Signature</name> + <fsummary>Sign the data using dsa with given private key.</fsummary> + <type> + <v>Digest = Mpint</v> + <v>Key = [P, Q, G, X]</v> + <v>P, Q, G, X = Mpint</v> + <d> Where <c>P</c>, <c>Q</c> and <c>G</c> are the dss + parameters and <c>X</c> is the private key.</d> + <v>Mpint = binary()</v> + <v>Signature = binary()</v> + </type> + <desc> + <p>Calculates the sha digest of the <c>Data</c> + and creates a DSS signature with the private key <c>Key</c> + of the digest.</p> + </desc> + </func> + + <func> + <name>dss_verify(Data, Signature, Key) -> Verified</name> + <fsummary>Verify the data and signature using dsa with given public key.</fsummary> + <type> + <v>Verified = boolean()</v> + <v>Digest, Signature = Mpint</v> + <v>Key = [P, Q, G, Y]</v> + <v>P, Q, G, Y = Mpint</v> + <d> Where <c>P</c>, <c>Q</c> and <c>G</c> are the dss + parameters and <c>Y</c> is the public key.</d> + <v>Mpint = binary()</v> + </type> + <desc> + <p>Calculates the sha digest of the <c>Data</c> and verifies that the + digest matches the DSS signature using the public key <c>Key</c>. + </p> + </desc> + </func> + + <func> + <name>rc4_encrypt(Key, Data) -> Result</name> + <fsummary>Encrypt data using RC4</fsummary> + <type> + <v>Key, Data = iolist() | binary()</v> + <v>Result = binary()</v> + </type> + <desc> + <p>Encrypts the data with RC4 symmetric stream encryption. + Since it is symmetric, the same function is used for + decryption.</p> + </desc> + </func> + + <func> + <name>dh_generate_key(DHParams) -> {PublicKey,PrivateKey} </name> + <name>dh_generate_key(PrivateKey, DHParams) -> {PublicKey,PrivateKey} </name> + <fsummary>Generates a Diffie-Hellman public key</fsummary> + <type> + <v>DHParameters = [P, G]</v> + <v>P, G = Mpint</v> + <d> Where <c>P</c> is the shared prime number and <c>G</c> is the shared generator.</d> + <v>PublicKey, PrivateKey = Mpint()</v> + </type> + <desc> + <p>Generates a Diffie-Hellman <c>PublicKey</c> and <c>PrivateKey</c> (if not given). + </p> + </desc> + </func> + + <func> + <name>dh_compute_key(OthersPublicKey, MyPrivateKey, DHParams) -> SharedSecret</name> + <fsummary>Computes the shared secret</fsummary> + <type> + <v>DHParameters = [P, G]</v> + <v>P, G = Mpint</v> + <d> Where <c>P</c> is the shared prime number and <c>G</c> is the shared generator.</d> + <v>OthersPublicKey, MyPrivateKey = Mpint()</v> + <v>SharedSecret = binary()</v> + </type> + <desc> + <p>Computes the shared secret from the private key and the other party's public key. + </p> + </desc> + </func> + + + <func> + <name>exor(Data1, Data2) -> Result</name> + <fsummary>XOR data</fsummary> + <type> + <v>Data1, Data2 = iolist() | binary()</v> + <v>Result = binary()</v> + </type> + <desc> + <p>Performs bit-wise XOR (exclusive or) on the data supplied.</p> + </desc> + </func> + </funcs> + + <section> + <title>DES in CBC mode</title> + <p>The Data Encryption Standard (DES) defines an algorithm for + encrypting and decrypting an 8 byte quantity using an 8 byte key + (actually only 56 bits of the key is used). + </p> + <p>When it comes to encrypting and decrypting blocks that are + multiples of 8 bytes various modes are defined (NIST SP + 800-38A). One of those modes is the Cipher Block Chaining (CBC) + mode, where the encryption of an 8 byte segment depend not only + of the contents of the segment itself, but also on the result of + encrypting the previous segment: the encryption of the previous + segment becomes the initializing vector of the encryption of the + current segment. + </p> + <p>Thus the encryption of every segment depends on the encryption + key (which is secret) and the encryption of the previous + segment, except the first segment which has to be provided with + an initial initializing vector. That vector could be chosen at + random, or be a counter of some kind. It does not have to be + secret. + </p> + <p>The following example is drawn from the old FIPS 81 standard + (replaced by NIST SP 800-38A), where both the plain text and the + resulting cipher text is settled. The following code fragment + returns `true'. + </p> + <pre><![CDATA[ + + Key = <<16#01,16#23,16#45,16#67,16#89,16#ab,16#cd,16#ef>>, + IVec = <<16#12,16#34,16#56,16#78,16#90,16#ab,16#cd,16#ef>>, + P = "Now is the time for all ", + C = crypto:des_cbc_encrypt(Key, IVec, P), + % Which is the same as + P1 = "Now is t", P2 = "he time ", P3 = "for all ", + C1 = crypto:des_cbc_encrypt(Key, IVec, P1), + C2 = crypto:des_cbc_encrypt(Key, C1, P2), + C3 = crypto:des_cbc_encrypt(Key, C2, P3), + + C = <<C1/binary, C2/binary, C3/binary>>, + C = <<16#e5,16#c7,16#cd,16#de,16#87,16#2b,16#f2,16#7c, + 16#43,16#e9,16#34,16#00,16#8c,16#38,16#9c,16#0f, + 16#68,16#37,16#88,16#49,16#9a,16#7c,16#05,16#f6>>, + <<"Now is the time for all ">> == + crypto:des_cbc_decrypt(Key, IVec, C). + ]]></pre> + <p>The following is true for the DES CBC mode. For all + decompositions <c>P1 ++ P2 = P</c> of a plain text message + <c>P</c> (where the length of all quantities are multiples of 8 + bytes), the encryption <c>C</c> of <c>P</c> is equal to <c>C1 ++ + C2</c>, where <c>C1</c> is obtained by encrypting <c>P1</c> with + <c>Key</c> and the initializing vector <c>IVec</c>, and where + <c>C2</c> is obtained by encrypting <c>P2</c> with <c>Key</c> + and the initializing vector <c>last8(C1)</c>, + where <c>last(Binary)</c> denotes the last 8 bytes of the + binary <c>Binary</c>. + </p> + <p>Similarly, for all decompositions <c>C1 ++ C2 = C</c> of a + cipher text message <c>C</c> (where the length of all quantities + are multiples of 8 bytes), the decryption <c>P</c> of <c>C</c> + is equal to <c>P1 ++ P2</c>, where <c>P1</c> is obtained by + decrypting <c>C1</c> with <c>Key</c> and the initializing vector + <c>IVec</c>, and where <c>P2</c> is obtained by decrypting + <c>C2</c> with <c>Key</c> and the initializing vector + <c>last8(C1)</c>, where <c>last8(Binary)</c> is as above. + </p> + <p>For DES3 (which uses three 64 bit keys) the situation is the + same. + </p> + </section> +</erlref> + |