How to convert SHA1 return value to ascii
I am trying to create a SHA1 hash of a user input and store it in a string value so I can compare it to a text file of known hashes.
To create the hash:
SHA1(password,strlen(password),temp);
print_hex(temp, sizeof(temp));
Convert the hash:
for(i=0;i<sizeof(passHash);i++)
sprintf(&passHash[i], "%02x", temp[i]);
printf("%sn", passHash);
Print_hex:
void print_hex(unsigned char *buf, int len)
int i;
for(i=0;i<len;i++)
printf("%02x",buf[i]);
printf("n");
When I run the program with a known hashed password like "password" it shows the right hash with print_hex but not after the sprintf. Therefore, I know I am converting the SHA1 hash incorrectly.
What am I doing wrong?
c sha1 data-conversion
asked Nov 12 '18 at 19:12
Colin G
256
add a comment |
I am trying to create a SHA1 hash of a user input and store it in a string value so I can compare it to a text file of known hashes.
To create the hash:
SHA1(password,strlen(password),temp);
print_hex(temp, sizeof(temp));
Convert the hash:
for(i=0;i<sizeof(passHash);i++)
sprintf(&passHash[i], "%02x", temp[i]);
printf("%sn", passHash);
Print_hex:
void print_hex(unsigned char *buf, int len)
int i;
for(i=0;i<len;i++)
printf("%02x",buf[i]);
printf("n");
When I run the program with a known hashed password like "password" it shows the right hash with print_hex but not after the sprintf. Therefore, I know I am converting the SHA1 hash incorrectly.
What am I doing wrong?
c sha1 data-conversion
asked Nov 12 '18 at 19:12
Colin G
256
1
what'spassHash? If it's a pointer,sizeof(passHash)probably won't give you what you want.
– yano
Nov 12 '18 at 20:13
You should never, ever be SHA1ing a user password. Traditional cryptographic hash functions are not intended for passwords. Instead, you should be using a password based key derivation function like bcrypt, scrypt, pbkdf2, or argon2. Here's why.
– TheGreatContini
Nov 12 '18 at 21:01
What do you get? What do you expect? have you read How to create a Minimal, Complete, and Verifiable example ?
– Luis Colorado
Nov 20 '18 at 8:27
add a comment |
I am trying to create a SHA1 hash of a user input and store it in a string value so I can compare it to a text file of known hashes.
To create the hash:
SHA1(password,strlen(password),temp);
print_hex(temp, sizeof(temp));
Convert the hash:
for(i=0;i<sizeof(passHash);i++)
sprintf(&passHash[i], "%02x", temp[i]);
printf("%sn", passHash);
Print_hex:
void print_hex(unsigned char *buf, int len)
int i;
for(i=0;i<len;i++)
printf("%02x",buf[i]);
printf("n");
When I run the program with a known hashed password like "password" it shows the right hash with print_hex but not after the sprintf. Therefore, I know I am converting the SHA1 hash incorrectly.
What am I doing wrong?
c sha1 data-conversion
asked Nov 12 '18 at 19:12
Colin G
256
I am trying to create a SHA1 hash of a user input and store it in a string value so I can compare it to a text file of known hashes.
To create the hash:
SHA1(password,strlen(password),temp);
print_hex(temp, sizeof(temp));
Convert the hash:
for(i=0;i<sizeof(passHash);i++)
sprintf(&passHash[i], "%02x", temp[i]);
printf("%sn", passHash);
Print_hex:
void print_hex(unsigned char *buf, int len)
int i;
for(i=0;i<len;i++)
printf("%02x",buf[i]);
printf("n");
When I run the program with a known hashed password like "password" it shows the right hash with print_hex but not after the sprintf. Therefore, I know I am converting the SHA1 hash incorrectly.
What am I doing wrong?
c sha1 data-conversion
c sha1 data-conversion
asked Nov 12 '18 at 19:12
Colin G
256
asked Nov 12 '18 at 19:12
Colin G
256
asked Nov 12 '18 at 19:12
Colin G
256
asked Nov 12 '18 at 19:12
Colin G
256
asked Nov 12 '18 at 19:12
Colin G
256
256
1
what'spassHash? If it's a pointer,sizeof(passHash)probably won't give you what you want.
– yano
Nov 12 '18 at 20:13
You should never, ever be SHA1ing a user password. Traditional cryptographic hash functions are not intended for passwords. Instead, you should be using a password based key derivation function like bcrypt, scrypt, pbkdf2, or argon2. Here's why.
– TheGreatContini
Nov 12 '18 at 21:01
What do you get? What do you expect? have you read How to create a Minimal, Complete, and Verifiable example ?
– Luis Colorado
Nov 20 '18 at 8:27
add a comment |
1
what'spassHash? If it's a pointer,sizeof(passHash)probably won't give you what you want.
– yano
Nov 12 '18 at 20:13
You should never, ever be SHA1ing a user password. Traditional cryptographic hash functions are not intended for passwords. Instead, you should be using a password based key derivation function like bcrypt, scrypt, pbkdf2, or argon2. Here's why.
– TheGreatContini
Nov 12 '18 at 21:01
What do you get? What do you expect? have you read How to create a Minimal, Complete, and Verifiable example ?
– Luis Colorado
Nov 20 '18 at 8:27
1
1
what's
passHash? If it's a pointer, sizeof(passHash) probably won't give you what you want.– yano
Nov 12 '18 at 20:13
what's
passHash? If it's a pointer, sizeof(passHash) probably won't give you what you want.– yano
Nov 12 '18 at 20:13
You should never, ever be SHA1ing a user password. Traditional cryptographic hash functions are not intended for passwords. Instead, you should be using a password based key derivation function like bcrypt, scrypt, pbkdf2, or argon2. Here's why.
– TheGreatContini
Nov 12 '18 at 21:01
You should never, ever be SHA1ing a user password. Traditional cryptographic hash functions are not intended for passwords. Instead, you should be using a password based key derivation function like bcrypt, scrypt, pbkdf2, or argon2. Here's why.
– TheGreatContini
Nov 12 '18 at 21:01
What do you get? What do you expect? have you read How to create a Minimal, Complete, and Verifiable example ?
– Luis Colorado
Nov 20 '18 at 8:27
What do you get? What do you expect? have you read How to create a Minimal, Complete, and Verifiable example ?
– Luis Colorado
Nov 20 '18 at 8:27
add a comment |
1 Answer
1
active
oldest
votes
You are overwriting in your converted string in consecutive sprintf calls. Check this:
char passHash[100] = 0,;
for(i=0;i<sizeof(temp);i++)
sprintf(passHash + i * 2, "%02x", temp[i]); // <-- each 2 bytes. e.g: 1 = 01, 255 = FF
printf("%sn", passHash);
Each byte takes 2 character in hex string, so you need to increase sprintf target buffer by 2. In addition, temp is the buffer that you are reading from, so your for loops should loops for sizeof(temp), not sizeof(passHash).
By the way, this is a sample code that shows your bug and I don't say this is best code.
answered Nov 12 '18 at 19:15
Afshin
2,9291624
add a comment |
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You are overwriting in your converted string in consecutive sprintf calls. Check this:
char passHash[100] = 0,;
for(i=0;i<sizeof(temp);i++)
sprintf(passHash + i * 2, "%02x", temp[i]); // <-- each 2 bytes. e.g: 1 = 01, 255 = FF
printf("%sn", passHash);
Each byte takes 2 character in hex string, so you need to increase sprintf target buffer by 2. In addition, temp is the buffer that you are reading from, so your for loops should loops for sizeof(temp), not sizeof(passHash).
By the way, this is a sample code that shows your bug and I don't say this is best code.
answered Nov 12 '18 at 19:15
Afshin
2,9291624
add a comment |
You are overwriting in your converted string in consecutive sprintf calls. Check this:
char passHash[100] = 0,;
for(i=0;i<sizeof(temp);i++)
sprintf(passHash + i * 2, "%02x", temp[i]); // <-- each 2 bytes. e.g: 1 = 01, 255 = FF
printf("%sn", passHash);
Each byte takes 2 character in hex string, so you need to increase sprintf target buffer by 2. In addition, temp is the buffer that you are reading from, so your for loops should loops for sizeof(temp), not sizeof(passHash).
By the way, this is a sample code that shows your bug and I don't say this is best code.
answered Nov 12 '18 at 19:15
Afshin
2,9291624
add a comment |
You are overwriting in your converted string in consecutive sprintf calls. Check this:
char passHash[100] = 0,;
for(i=0;i<sizeof(temp);i++)
sprintf(passHash + i * 2, "%02x", temp[i]); // <-- each 2 bytes. e.g: 1 = 01, 255 = FF
printf("%sn", passHash);
Each byte takes 2 character in hex string, so you need to increase sprintf target buffer by 2. In addition, temp is the buffer that you are reading from, so your for loops should loops for sizeof(temp), not sizeof(passHash).
By the way, this is a sample code that shows your bug and I don't say this is best code.
answered Nov 12 '18 at 19:15
Afshin
2,9291624
You are overwriting in your converted string in consecutive sprintf calls. Check this:
char passHash[100] = 0,;
for(i=0;i<sizeof(temp);i++)
sprintf(passHash + i * 2, "%02x", temp[i]); // <-- each 2 bytes. e.g: 1 = 01, 255 = FF
printf("%sn", passHash);
Each byte takes 2 character in hex string, so you need to increase sprintf target buffer by 2. In addition, temp is the buffer that you are reading from, so your for loops should loops for sizeof(temp), not sizeof(passHash).
By the way, this is a sample code that shows your bug and I don't say this is best code.
answered Nov 12 '18 at 19:15
Afshin
2,9291624
edited Nov 12 '18 at 19:27
answered Nov 12 '18 at 19:15
Afshin
2,9291624
answered Nov 12 '18 at 19:15
Afshin
2,9291624
answered Nov 12 '18 at 19:15
Afshin
2,9291624
2,9291624
add a comment |
add a comment |
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1
what's
passHash? If it's a pointer,sizeof(passHash)probably won't give you what you want.– yano
Nov 12 '18 at 20:13
You should never, ever be SHA1ing a user password. Traditional cryptographic hash functions are not intended for passwords. Instead, you should be using a password based key derivation function like bcrypt, scrypt, pbkdf2, or argon2. Here's why.
– TheGreatContini
Nov 12 '18 at 21:01
What do you get? What do you expect? have you read How to create a Minimal, Complete, and Verifiable example ?
– Luis Colorado
Nov 20 '18 at 8:27