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Add the SM4 block cipher, also a no-padding option for block ciphers.

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This adds an implementation of the SM4 block cipher, and operations
to encrypt and decrypt using it with CBC,ECB,CFB,OFB,CTR modes.

Also, a "no padding" option is added for AES,DES,3DES and SM4
decryption in ECB/CBC modes. This variant does not attempt to
validate the last block as being PKCS#7 padded.

This is useful, both since other padding schemes exist, and also
for decrypting data where the final block is missing.
This commit is contained in:
swesven 2021-03-24 00:58:54 +01:00
parent 5029356514
commit 6155634d3b
9 changed files with 821 additions and 7 deletions
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13
src/core/operations/DESDecrypt.mjs
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@ -22,7 +22,7 @@ class DESDecrypt extends Operation {
this.name = "DES Decrypt";
this.module = "Ciphers";
this.description = "DES is a previously dominant algorithm for encryption, and was published as an official U.S. Federal Information Processing Standard (FIPS). It is now considered to be insecure due to its small key size.<br><br><b>Key:</b> DES uses a key length of 8 bytes (64 bits).<br>Triple DES uses a key length of 24 bytes (192 bits).<br><br><b>IV:</b> The Initialization Vector should be 8 bytes long. If not entered, it will default to 8 null bytes.<br><br><b>Padding:</b> In CBC and ECB mode, PKCS#7 padding will be used.";
this.description = "DES is a previously dominant algorithm for encryption, and was published as an official U.S. Federal Information Processing Standard (FIPS). It is now considered to be insecure due to its small key size.<br><br><b>Key:</b> DES uses a key length of 8 bytes (64 bits).<br>Triple DES uses a key length of 24 bytes (192 bits).<br><br><b>IV:</b> The Initialization Vector should be 8 bytes long. If not entered, it will default to 8 null bytes.<br><br><b>Padding:</b> In CBC and ECB mode, PKCS#7 padding will be used as a default.";
this.infoURL = "https://wikipedia.org/wiki/Data_Encryption_Standard";
this.inputType = "string";
this.outputType = "string";
@ -42,7 +42,7 @@ class DESDecrypt extends Operation {
{
"name": "Mode",
"type": "option",
"value": ["CBC", "CFB", "OFB", "CTR", "ECB"]
"value": ["CBC", "CFB", "OFB", "CTR", "ECB", "CBC/NoPadding", "ECB/NoPadding"]
},
{
"name": "Input",
@ -65,7 +65,8 @@ class DESDecrypt extends Operation {
run(input, args) {
const key = Utils.convertToByteString(args[0].string, args[0].option),
iv = Utils.convertToByteArray(args[1].string, args[1].option),
[,, mode, inputType, outputType] = args;
mode = args[2].substring(0, 3),
[,,, inputType, outputType] = args;
if (key.length !== 8) {
throw new OperationError(`Invalid key length: ${key.length} bytes
@ -83,6 +84,12 @@ Make sure you have specified the type correctly (e.g. Hex vs UTF8).`);
input = Utils.convertToByteString(input, inputType);
const decipher = forge.cipher.createDecipher("DES-" + mode, key);
/* Allow for a "no padding" mode */
if (args[2].endsWith("NoPadding")) {
decipher.mode.unpad = function(output, options) {
return true;
};
}
decipher.start({iv: iv});
decipher.update(forge.util.createBuffer(input));
const result = decipher.finish();