CLIAMS:1. A method for generating a randomized message for a cryptographic hash function, the method comprising:
obtaining, by a processor (108), a random value in a binary bit form for randomizing a message;
splitting, by the processor (108), the message into multiple message blocks, wherein a length of each of the multiple message blocks is based on a length of the random value and a block length of a compression function;
prepending and appending, by the processor (108), each of the multiple message blocks with at least a portion of the random value; and
concatenating, by the processor (108), the prepended and appended message blocks to obtain a message envelope for generating the randomized message.
2. The method as claimed in claim 1, wherein the length of each of the multiple message blocks is equal to the block length of the compression function minus twice the length of the random value.
3. The method as claimed in claim 1 further comprising:
concatenating the random value to itself a predefined number of times to obtain a concatenated random value, wherein a length of the concatenated random value is equal to the block length of the compression function; and
prefixing the concatenated random value to the message envelope.
4. The method as claimed in claim 3 further comprising:
suffixing a first predefined number of bits of the concatenated random value to the message envelope to generate the randomized message, wherein the first predefined number of bits is based on a number of bits for hash function padding and the length of the concatenated random value.
5. The method as claimed in claim 4 further comprising:
applying a predefined cryptographic hash function on the randomized message to obtain a randomized hash value.
6. The method as claimed in claim 5 further comprising:
applying a predefined digital signature scheme on the randomized hash value to obtain a digital signature bit string.
7. A randomized message generating system (102) comprising:
a processor (108); and
a message envelope generator (118) coupled to the processor (108) to,
obtain a random value in a binary bit form for randomizing a message;
split the message into multiple message blocks, wherein a length of each of the multiple message blocks is based on a length of the random value and a block length of a compression function;
prepend and append each of the multiple message blocks with at least a portion of the random value; and
concatenate the prepended and appended message blocks to obtain a message envelope for generating the randomized message.
8. The randomized message generating system (102) as claimed in claim 7, wherein the length of each of the multiple message blocks is equal to the block length of the compression function minus twice the length of the random value.
9. The randomized message generating system (102) as claimed in claim 7 further comprising a prefix-message envelope-suffix (PMES) message generator (120) coupled to the processor (108) to,
concatenate the random value to itself a predefined number of times to obtain a concatenated random value, wherein a length of the concatenated random value is equal to the block length of the compression function; and
prefix the concatenated random value to the message envelope.
10. The randomized message generating system (102) as claimed in claim 9, wherein the PMES message generator (120) is coupled to the processor (108) to,
suffix a first predefined number of bits of the concatenated random value to the message envelope to generate the randomized message, wherein a length of the first predefined number of bits is equal to the length of the concatenated random value minus a number of bits for hash function padding.
11. The randomized message generating system (102) as claimed in claim 10 further comprising a randomized hash value generator (122) coupled to the processor (108) to,
generate a randomized hash value by applying a predefined cryptographic hash function on the randomized message.
12. The randomized message generating system (102) as claimed in claim 11 further comprising a digital signature generator (124) coupled to the processor (108) to,
generate a digital signature bit string by applying a predefined digital signature scheme on the randomized hash value.
13. A non-transitory computer-readable medium having embodied thereon a computer program for executing a method for generating a randomized message for a cryptographic hash function, the method comprising:
obtaining a random value in a binary bit form for randomizing a message;
splitting the message into multiple message blocks, wherein a length of each of the multiple message blocks is based on a length of the random value and a block length of a compression function;
prepending and appending each of the multiple message blocks with at least a portion of the random value; and
concatenating the prepended and appended message blocks to obtain a message envelope for generating the randomized message.
14. The non-transitory computer-readable medium as claimed in claim 13, wherein the length of each of the multiple message blocks is equal to the block length of the compression function minus twice the length of the random value.
15. The non-transitory computer-readable medium as claimed in claim 13, wherein the method further comprises:
concatenating the random value to itself a predefined number of times to obtain a concatenated random value, wherein a length of the concatenated random value is equal to the block length of the compression function;
prefixing the concatenated random value to the message envelope; and
suffixing a first predefined number of bits of the concatenated random value to the message envelope to generate the randomized message, wherein the first predefined number of bits is based on a number of bits for hash function padding and the length of the concatenated random value.
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