Difference between revisions of "83Plus:BCALLs:8090"

From WikiTI
Jump to: navigation, search
(Outputs)
m (Example)
 
(11 intermediate revisions by 2 users not shown)
Line 1: Line 1:
 +
[[Category:83Plus:BCALLs:By Name:Cryptography|MD5Update]] [[Category:83Plus:BCALLs:By Name|MD5Update]] [[Category:83Plus:BCALLs:By Address|8090 - MD5Update]]
 
== Synopsis ==
 
== Synopsis ==
 
'''Official Name:''' MD5Update
 
'''Official Name:''' MD5Update
Line 13: Line 14:
  
 
=== Outputs ===
 
=== Outputs ===
* [[83Plus:RAM:8269|8269]]: (4 bytes) Holds the length in bits of the data hashed so far.
+
* [[83Plus:RAM:8269|8269]]: (8 bytes) Holds the length in bits of the data hashed so far.
 
* [[83Plus:RAM:8292|8292]]: (16 bytes) Will be changed to contain the new (incremental) MD5 hash of the data you gave it
 
* [[83Plus:RAM:8292|8292]]: (16 bytes) Will be changed to contain the new (incremental) MD5 hash of the data you gave it
  
 
=== Destroys ===
 
=== Destroys ===
Unkown, please add this when you test check this out.
+
* [[83Plus:RAM:8259|8259]]: (16 bytes) Alternate registers (roughly equivalent to the AA, BB, CC, and DD registers specified in the MD5 standard.)
 +
* [[83Plus:RAM:83A5|83A5]]: (64 bytes) Buffer holding data to be hashed.
  
 
== Comments ==
 
== Comments ==
This B_CALL incrementally changes the md5 "registers" for the data you give it. But it does not add the size word that is required to generate official MD5 hashes, you have to do this yourself if you want official hashes.
+
This B_CALL incrementally changes the MD5 "registers" for the data you give it. Note that the registers must be initialized using [[83Plus:BCALLs:808D|MD5Init]] first.  You can call this B_CALL as many times as you want to add many separate chunks of data to the hash.  To complete the MD5 hash, use [[83Plus:BCALLs:8018|MD5Final]].
  
 
== Example ==
 
== Example ==
  <nowiki>B_CALL InitializeMD5
+
  B_CALL [[83Plus:BCALLs:808D|MD5Init]]
ld bc,0040h
+
ld bc,14
ld hl,SomeAddress
+
ld hl,String
B_CALL CalculateMD5</nowiki>
+
B_CALL MD5Update
 +
B_CALL [[83Plus:BCALLs:8018|MD5Final]]
 +
; should give: f96b697d7cb7938d525a2f31aaf161d0
 +
 +
String: .db "message digest"
  
 
== Credits and Contributions ==
 
== Credits and Contributions ==
 
* '''FloppusMaximus:''' For testing that this B_CALL also work with lengths unequal to 64 bytes
 
* '''FloppusMaximus:''' For testing that this B_CALL also work with lengths unequal to 64 bytes

Latest revision as of 14:34, 30 March 2005

Synopsis

Official Name: MD5Update

Other Name: CalculateMD5

BCALL Address: 8090

Calculates the MD5 checksum

Inputs

  • BC: The length of the data
  • HL: The location of the data

Outputs

  • 8269: (8 bytes) Holds the length in bits of the data hashed so far.
  • 8292: (16 bytes) Will be changed to contain the new (incremental) MD5 hash of the data you gave it

Destroys

  • 8259: (16 bytes) Alternate registers (roughly equivalent to the AA, BB, CC, and DD registers specified in the MD5 standard.)
  • 83A5: (64 bytes) Buffer holding data to be hashed.

Comments

This B_CALL incrementally changes the MD5 "registers" for the data you give it. Note that the registers must be initialized using MD5Init first. You can call this B_CALL as many times as you want to add many separate chunks of data to the hash. To complete the MD5 hash, use MD5Final.

Example

B_CALL MD5Init
ld bc,14
ld hl,String
B_CALL MD5Update
B_CALL MD5Final
; should give: f96b697d7cb7938d525a2f31aaf161d0

String: .db "message digest"

Credits and Contributions

  • FloppusMaximus: For testing that this B_CALL also work with lengths unequal to 64 bytes